Mammal classification
Encyclopedia
Mammalia is a class of animal within the Phylum Chordata. Mammal classification has been through several iterations since Carolus Linnaeus
Carolus Linnaeus
Carl Linnaeus , also known after his ennoblement as , was a Swedish botanist, physician, and zoologist, who laid the foundations for the modern scheme of binomial nomenclature. He is known as the father of modern taxonomy, and is also considered one of the fathers of modern ecology...

 initially defined the class. Many earlier ideas have been completely abandoned by modern taxonomists, among these are the idea that bat
Bat
Bats are mammals of the order Chiroptera "hand" and pteron "wing") whose forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums, and colugos, glide rather than fly,...

s are related to bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

s or that human
Human
Humans are the only living species in the Homo genus...

s represent a completely distinct group. Competing ideas about the relationships of mammal orders do persist and are currently in development. Most significantly in recent years, cladistic
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...

 thinking has led to an effort to ensure that all taxonomic designations represent monophyletic groups. The field has also seen a recent surge in interest and modification due to the results of molecular phylogenetics
Molecular phylogeny
Molecular phylogenetics is the analysis of hereditary molecular differences, mainly in DNA sequences, to gain information on an organism's evolutionary relationships. The result of a molecular phylogenetic analysis is expressed in a phylogenetic tree...

.

George Gaylord Simpson
George Gaylord Simpson
George Gaylord Simpson was an American paleontologist. Simpson was perhaps the most influential paleontologist of the twentieth century, and a major participant in the modern evolutionary synthesis, contributing Tempo and mode in evolution , The meaning of evolution and The major features of...

's classic "Principles of Classification and a Classification of Mammals" (Simpson, 1945) was the original source for the taxonomy
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...

 listed here. Simpson laid out a systematics
Systematics
Biological systematics is the study of the diversification of terrestrial life, both past and present, and the relationships among living things through time. Relationships are visualized as evolutionary trees...

 of mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...

 origins and relationships that was universally taught until the end of the 20th century.

Since Simpson's 1945 classification, the paleontological record has been recalibrated, and the intervening years have seen much debate and progress concerning the theoretical underpinnings of systematization itself, partly through the new concept of cladistics
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...

. Though field work gradually made Simpson's classification outdated, it remained the closest thing to an official classification of mammals.

Molecular classification of mammals

Molecular studies by molecular systematist
Molecular phylogeny
Molecular phylogenetics is the analysis of hereditary molecular differences, mainly in DNA sequences, to gain information on an organism's evolutionary relationships. The result of a molecular phylogenetic analysis is expressed in a phylogenetic tree...

s, based on DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

 analysis, have revealed new relationships among mammal families over the last few years. The most recent classification systems based on molecular studies reveal four groups or lineages of placental mammals which diverged from early common ancestors in the Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...

.

The first divergence was that of the Afrotheria
Afrotheria
Afrotheria is a clade of mammals, the living members of which belong to groups from Africa or of African origin: golden moles, sengis , tenrecs, aardvarks, hyraxes, elephants and sea cows. The common ancestry of these animals was not recognized until the late 1990s...

  110–100 million years ago (mya). The Afrotheria proceeded to evolve and diversify in the isolation of the African-Arabian continent. The Xenarthra
Xenarthra
The superorder Xenarthra is a group of placental mammals , existent today only in the Americas and represented by anteaters, tree sloths, and armadillos. The origins of the order can be traced back as far as the Paleogene in South America...

, isolated in South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

, diverged from the Boreoeutheria
Boreoeutheria
Boreoeutheria is a clade of placental mammals that is composed of the sister taxa Laurasiatheria and Euarchontoglires...

 approximately 100–95 mya. The Boreoeutheria split into the Laurasiatheria
Laurasiatheria
Laurasiatheria is a large group of placental mammals believed to have originated on the northern supercontinent of Laurasia. It includes shrews, hedgehogs, pangolins, bats, whales, most hoofed mammals, and carnivorans, among others....

 and Euarchontoglires
Euarchontoglires
Euarchontoglires is a clade of mammals, the living members of which are rodents, lagomorphs, treeshrews, colugos and primates .-Evolutionary relationships:...

 between 95 and 85 mya; both of these groups evolved on the northern continent of Laurasia
Laurasia
In paleogeography, Laurasia was the northernmost of two supercontinents that formed part of the Pangaea supercontinent from approximately...

.

After tens of millions of years of relative isolation, Africa-Arabia collided with Eurasia, and the formation of the Isthmus of Panama
Isthmus of Panama
The Isthmus of Panama, also historically known as the Isthmus of Darien, is the narrow strip of land that lies between the Caribbean Sea and the Pacific Ocean, linking North and South America. It contains the country of Panama and the Panama Canal...

 linked South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

 and North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

, facilitating the distribution of mammals seen today. With the exception of bats and murine
Murinae
The Old World rats and mice, part of the subfamily Murinae in the family Muridae, comprise at least 519 species. This subfamily is larger than all mammal families except the Cricetidae and Muridae, and is larger than all mammal orders except the bats and the remainder of the...

 rodents, no placental land mammals reached Australasia
Australasia
Australasia is a region of Oceania comprising Australia, New Zealand, the island of New Guinea, and neighbouring islands in the Pacific Ocean. The term was coined by Charles de Brosses in Histoire des navigations aux terres australes...

 until the first human settlers arrived approximately 50,000 years ago.

It should however be noted that these molecular results are still controversial mainly because they are not reflected by morphological
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....

 data and thus not accepted by many systematists. It is also important to note that fossil taxa are not and, in most cases cannot, be included. Although there are instances of DNA being recovered from prehistoric mammals such as the ground sloth
Ground sloth
Ground sloths are a diverse group of extinct sloths, in the mammalian superorder Xenarthra. Their most recent survivors lived in the Antilles, where it has been proposed they may have survived until 1550 CE; however, the youngest AMS radiocarbon date reported is 4190 BP, calibrated to c. 4700 BP...

 Mylodon
Mylodon
Mylodon is an extinct genus of giant ground sloth that lived in the Patagonia area of South America until roughly 10,000 years ago.Mylodon weighed about and stood up to tall when raised up on its hind legs. Preserved dung has shown it was a herbivore. It had very thick hide and had osteoderms...

and Neanderthal
Neanderthal
The Neanderthal is an extinct member of the Homo genus known from Pleistocene specimens found in Europe and parts of western and central Asia...

 humans, Homo neanderthalensis, fossils can generally only be incorporated in morphological analyses.

The following taxonomy only includes living placentals (infraclass Eutheria
Eutheria
Eutheria is a group of mammals consisting of placental mammals plus all extinct mammals that are more closely related to living placentals than to living marsupials . They are distinguished from noneutherians by various features of the feet, ankles, jaws and teeth...

):

Group I: Afrotheria
Afrotheria
Afrotheria is a clade of mammals, the living members of which belong to groups from Africa or of African origin: golden moles, sengis , tenrecs, aardvarks, hyraxes, elephants and sea cows. The common ancestry of these animals was not recognized until the late 1990s...

 (79 species)

  • Clade Afroinsectiphilia
    Afroinsectiphilia
    The Afroinsectiphilia is a clade that has been proposed based on the results of recent molecular studies. Many of its orders were once regarded as part of the order Insectivora, but Insectivora is now considered to be polyphyletic and is, as a result, possibly obsolete...

    • Order Macroscelidea
      • Family Macroscelididae: (16 species), elephant shrews (Africa)
    • Order Afrosoricida
      Afrosoricida
      The order Afrosoricida contains the golden moles of southern Africa and the tenrecs of Madagascar and Africa, two families of small mammals that have traditionally been considered to be a part of the order Insectivora.Some biologists use Tenrecomorpha as the name for the tenrec-golden mole clade,...

      • Family Tenrecidae
        Tenrecidae
        Tenrecidae is a family of mammals found on Madagascar and parts of Africa. Tenrecs are widely diverse, resembling hedgehogs, shrews, opossums, mice and even otters, as a result of convergent evolution. They occupy aquatic, arboreal, terrestrial and fossorial environments...

        : (30 species), tenrecs (Madagascar) and otter-shrews (West and Central Africa)
      • Family Chrysochloridae: (21 species), golden moles (Africa south of the Sahara)
    • Order Tubulidentata
      • Family Orycteropodidae
        Orycteropodidae
        Orycteropodidae is a family of afrotherian mammals. Although there are many fossil species, the only species surviving today is the aardvark, Orycteropus afer. Orycteropodidae is recognized as the only family within the order Tubulidentata, so the two are effectively synonyms.The family arose in...

        : (1 species), aardvark (Africa south of the Sahara)
  • Clade Paenungulata
    Paenungulata
    Paenungulata is a taxon that groups some remarkable mammals, including three orders that are extant: Proboscidea , Sirenia , and Hyracoidea . At least two more orders are known only as fossils, namely Embrithopoda and Desmostylia...

    • Order Proboscidea
      Proboscidea
      Proboscidea is a taxonomic order containing one living family, Elephantidae, and several extinct families. This order was first described by J. Illiger in 1881 and encompasses the trunked mammals...

      • Family Elephantidae
        Elephantidae
        Elephantidae is a taxonomic family, collectively elephants and mammoths. These are terrestrial large mammals with a trunk and tusks. Most genera and species in the family are extinct...

        : (3 species), elephants (Africa, Southeast Asia)
    • Order Hyracoidea
      • Family Procaviidae: (4 species), hyraxes, dassies (Africa, Arabia)
    • Order Sirenia
      Sirenia
      Sirenia is an order of fully aquatic, herbivorous mammals that inhabit swamps, rivers, estuaries, marine wetlands, and coastal marine waters. Four species are living, in two families and genera. These are the dugong and manatees...

      • Family Dugongidae
        Dugongidae
        Dugongidae is a family in the order of Sirenia.The family has one surviving species, the Dugong , one recently extinct species, the Steller's Sea Cow , and a number of extinct genera known from the fossil record....

        : (1 species), dugong (East Africa, Red Sea, North Australia)
      • Family Trichechidae: (3 species), manatees (tropical Atlantic coasts and adjacent rivers)

Group II: Xenarthra
Xenarthra
The superorder Xenarthra is a group of placental mammals , existent today only in the Americas and represented by anteaters, tree sloths, and armadillos. The origins of the order can be traced back as far as the Paleogene in South America...

 (29 species)

  • Order Cingulata
    • Family Dasypodidae: (20 species), armadillos (Neotropical and Nearctic)
  • Order Pilosa
    Pilosa
    The order Pilosa is a group of placental mammals, extant today only in the Americas. It includes the anteaters and sloths, including the recently extinct ground sloths....

    • Family Myrmecophagidae
      Myrmecophagidae
      Myrmecophagidae is a family of anteaters, the name being derived from the Ancient Greek words for 'ant' and 'eat' . Myrmecophagids are native to Central and South America, from southern Mexico to northern Argentina. There are 2 genera and 3 species in the family, consisting of the Giant Anteater,...

      : (3 species), anteaters (Neotropical)
    • Family Megalonychidae
      Megalonychidae
      Megalonychidae is a group of sloths including the extinct Megalonyx and the living two toed sloths. Megalonychids first appeared in the early Oligocene, about 35 million years ago, in southern Argentina , and spread as far as the Antilles by the early Miocene...

      : (2 species), two-toed sloths (Neotropical)
    • Family Bradypodidae: (4 species), three-toed sloths (Neotropical)

Group III Euarchontoglires
Euarchontoglires
Euarchontoglires is a clade of mammals, the living members of which are rodents, lagomorphs, treeshrews, colugos and primates .-Evolutionary relationships:...

  • Superorder Euarchonta
    Euarchonta
    The Euarchonta are a grandorder of mammals containing four orders: the Dermoptera or colugos, the Scandentia or treeshrews, the extinct Plesiadapiformes, and the Primates....

    • Order Scandentia
      • Family Ptilocercidae (1 species), Pen-tailed Treeshrews (Southeast Asia)
      • Family Tupaiidae
        Tupaiidae
        Tupaiidae is one of two families of treeshrews, the other family being Ptilocercidae. It contains 4 genera and 19 species.-Taxonomy:*Order: Scandentia** Family Tupaiidae*** Genus Anathana**** Madras Treeshrew, Anathana ellioti...

        : (19 species), treeshrews (Southeast Asia)
    • Clade Primatomorpha
      Primatomorpha
      The Primatomorpha are a mirorder of mammals containing two orders: the Dermoptera or colugos and the Primates ....

      • Order Dermoptera
        • Family Cynocephalidae: (2 species), flying lemurs or colugos (Southeast Asia)
      • Order Primates: lemurs, bushbabies, monkeys, apes (cosmopolitan
        Cosmopolitan distribution
        In biogeography, a taxon is said to have a cosmopolitan distribution if its range extends across all or most of the world in appropriate habitats. For instance, the killer whale has a cosmopolitan distribution, extending over most of the world's oceans. Other examples include humans, the lichen...

        ).
        • Family Cheirogaleidae
          Cheirogaleidae
          Cheirogaleidae is the family of strepsirrhine primates that contains the various dwarf and mouse lemurs. Like all other lemurs, cheirogaleids live exclusively on the island of Madagascar.-Characteristics:...

          : (32 species),dwarf lemurs (Madagascar)
        • Family Lemuridae
          Lemuridae
          Lemuridae is a family of prosimian primates native to Madagascar, and one of five families commonly known as lemurs. These animals were thought to be the evolutionary predecessors of monkeys and apes, but this is no longer considered correct...

          : (22 species),lemurs (Madagascar)
        • Family Lepilemuridae: (26 species),sportive lemurs (Madagascar)
        • Family Indriidae
          Indriidae
          The Indriidae are a family of strepsirrhine primates. They are medium to large sized lemurs with only four teeth in the toothcomb instead of the usual six...

          : (19 species),indri and sifakas (Madagascar)
        • Family Daubentoniidae: (1 species),aye-aye (Madagascar area)
        • Family Lorisidae
          Lorisidae
          Lorisidae is a family of strepsirrhine primates. The lorisids are all slim arboreal animals and include the lorises, pottos and angwantibos. Lorisids live in tropical, central Africa as well as in south and southeast Asia....

          : (9 species),lorises and potto (Africa and Southeast Asia)
        • Family Galagidae: (19 species),galagos (Africa)
        • Family Tarsiidae: (9 species),tarsiers (Southeast Asia)
        • Family Callitrichidae: (41 species),marmosets and tamarins (South America)
        • Family Cebidae
          Cebidae
          The Cebidae is one of the five families of New World monkeys now recognised. It includes the capuchin monkeys and squirrel monkeys. These species are found throughout tropical and subtropical South and Central America.-Characteristics:...

          : (14 species),New World monkeys (South America)
        • Family Cercopithecidae: (137 species),Old World monkeys (Africa and Eurasia)
        • Family Hylobatidae: (14 species),gibbons (Southeast Asia)
        • Family Hominidae
          Hominidae
          The Hominidae or include them .), as the term is used here, form a taxonomic family, including four extant genera: chimpanzees , gorillas , humans , and orangutans ....

          : (7 species),great apes (worldwide)
  • Superorder Glires
    Glires
    Glires is a clade consisting of rodents and lagomorphs . This hypothesis that these form a monophyletic group has been long debated based on morphological evidence, although recent morphological studies strongly support monophyly of Glires...

    • Order Lagomorpha
      Lagomorpha
      The lagomorphs are the members of the taxonomic order Lagomorpha, of which there are two living families, the Leporidae , and the Ochotonidae...

      : pikas, rabbits, hares (Eurasia, Africa, Americas)
      • Family Leporidae
        Leporidae
        Leporids are the approximately 50 species of rabbits and hares which form the family Leporidae. The leporids, together with the pikas, constitute the mammalian order Lagomorpha. Leporids differ from pikas in having short furry tails, and elongated ears and hind legs...

        : (60 species),rabbits and hares (Eurasia, Africa, Americas)
      • Family Ochotonidae: (30 species),pikas (Holarctic)
    • Order Rodentia: rodents (cosmopolitan)
      • Family Aplodontiidae: mountain beaver (North America)
      • Family Sciuridae: squirrels, chipmunks, and marmots (cosmopolitan except Australia)
      • Family Gliridae: dormice (Africa, Eurasia)
      • Family Castoridae
        Castoridae
        The family Castoridae contains the two living species of beaver and their fossil relatives. This was once a highly diverse group of rodents, but is now restricted to a single genus, Castor.- Characteristics :...

        : beavers (Holarctic)
      • Family Geomyidae: pocket gophers (North America)
      • Family Heteromyidae
        Heteromyidae
        The family of rodents that include kangaroo rats, kangaroo mice and rock pocket mice is the Heteromyidae family. Most heteromyids live in complex burrows within the deserts and grasslands of western North America, though species within the Heteromys and Liomys genera are also found in forests and...

        : kangaroo rats (North America)
      • Family Dipodidae
        Dipodidae
        The Dipodidae, or dipodids, are a family of rodents found across the northern hemisphere. This family includes over 50 species among the 16 genera....

        : jerboas and jumping mice (Africa, Eurasia, North America)
      • Family Platacanthomyidae: spiny dormouse (Southeast Asia)
      • Family Spalacidae
        Spalacidae
        The Spalacidae, or spalacids are a family of rodents in the large and complex superfamily Muroidea. They are native to eastern Asia, the Horn of Africa, the Middle East, and south-eastern Europe. It includes the blind mole rats, bamboo rats, root rats, and zokors...

        : zokors, root rats, blind mole rats (Africa, Eurasia)
      • Family Calomyscidae: mouse-like hamsters (Asia)
      • Family Nesomyidae
        Nesomyidae
        Nesomyidae is a family of African rodents in the large and complex superfamily Muroidea. It includes several subfamilies, all of which are native to either continental Africa or to Madagascar...

        : old endemic African muroids (Africa, Madagascar)
      • Family Cricetidae
        Cricetidae
        The Cricetidae are a family of rodents in the large and complex superfamily Muroidea. It includes true hamsters, voles, lemmings, and New World rats and mice...

        : hamsters, voles, and New World rats and mice (Holarctic, South America)
      • Family Muridae
        Muridae
        Muridae is the largest family of mammals. It contains over 600 species found naturally throughout Eurasia, Africa, and Australia. They have been introduced worldwide. The group includes true mice and rats, gerbils, and relatives....

        : Old World rats and mice and gerbils (Africa, Eurasia, Australia)
      • Family Anomaluridae: scaly-tailed flying squirrels (Africa)
      • Family Pedetidae
        Pedetidae
        Pedetidae is a family of mammals from the rodent order. The two living species, the springhares, are distributed throughout much of southern Africa and also around Kenya, Tanzania and Uganda. Fossils have been found as far north as Turkey. Together with the anomalures, Pedetidae forms the suborder...

        : springhaas (Africa)
      • Family Ctenodactylidae: gundis (Africa, Asia)
      • Family Hystricidae: Old World porcupines (Africa, Asia)
      • Family Bathyergidae: African mole-rats (Africa)
      • Family Petromuridae: rock dassies (Africa)
      • Family Thryonomyidae: cane rats (Africa)
      • Family Erethizontidae: New World porcupines (New World)
      • Family Chinchillidae
        Chinchillidae
        The family Chinchillidae contains the chinchillas, viscachas, and their fossil relatives. They are restricted to southern and western South America, often in association with the Andes. They are large rodents, weighing from to , with strong hind legs and large ears...

        : chinchillas and viscachas (South America)
      • Family Dinomyidae
        Dinomyidae
        Dinomyidae was once a very speciose group of South American hystricognath rodent, but now contains only a single living species, the Pacarana. The Dinomyidae included among its ranks the largest rodents known to date, the bison-sized Josephoartigasia monesi and the smaller Josephoartigasia magna...

        : pacarana (South America)
      • Family Caviidae
        Caviidae
        The cavy family is a family of rodents native to South America, and including the domestic guinea pig, wild cavies, and the capybara, among other animals...

        : cavies and capybara (South America)
      • Family Dasyproctidae
        Dasyproctidae
        Dasyproctidae is a family of large South American rodents, comprising the agoutis and acouchis. Their fur is a reddish or dark colour above, with a paler underside. They are herbivorous, often feeding on ripe fruit that falls from trees...

        : agoutis and acouchis (South America)
      • Family Agoutidae: paca (South America)
      • Family Ctenomyidae: tuco-tucos (South America)
      • Family Octodontidae
        Octodontidae
        The Octodontidae are a family of rodents, restricted to south-western South America. Thirteen species of octodontid are recognised, arranged in nine genera. The best known species is the Degu, Octodon degus....

        : degus (South America)
      • Family Abrocomidae: chinchilla-rats (South America)
      • Family Echimyidae: spiny rats (South America)
      • Family Capromyidae: hutias (South America)
      • Family Myocastoridae: nutrias (South America)

Group IV: Laurasiatheria
Laurasiatheria
Laurasiatheria is a large group of placental mammals believed to have originated on the northern supercontinent of Laurasia. It includes shrews, hedgehogs, pangolins, bats, whales, most hoofed mammals, and carnivorans, among others....

  • Order Eulipotyphla
    • Family Solenodontidae
      Solenodontidae
      Solenodons are venomous, nocturnal, burrowing, insectivorous mammals belonging to the family Solenodontidae. Only one genus, Solenodon, is known, although a few other genera were erected at one time and are now regarded as junior synonyms...

      : solenodons (Cuba, Hispaniola)
    • Family Soricidae: shrews (Eurasia, Africa, North America to northern South America)
    • Family Talpidae
      Talpidae
      The family Talpidae includes the moles, shrew moles, desmans, and other intermediate forms of small insectivorous mammals of the order Soricomorpha...

      : moles, shrew-moles, desmans (Eurasia, North America)
    • Family Erinaceidae
      Erinaceidae
      Erinaceidae is the only living family in the order Erinaceomorpha, which has recently been subsumed with Soricomorpha into the order Eulipotyphla...

      : hedgehogs, moonrats (Eurasia, Africa)
  • Clade Ferungulata
    Ferungulata
    Ferungulata is traditionally a clade with the rank of cohort within the placental mammals. Established by George Gaylord Simpson in 1945, it includes the Carnivora, Perissodactyla and Artiodactyla as well as Tubulidentata and a superorder, Paenungulata, plus a number of orders known only as fossils...

    • Cohort Cetartiodactyla
      Cetartiodactyla
      Cetartiodactyla is the clade in which whales and even-toed ungulates have currently been placed. The term was coined by merging the name for the two orders, Cetacea and Artiodactyla, into a single word. The term Cetartiodactyla reflects the idea that whales evolved within the artiodactyls...

      : includes orders Artiodactyla and Cetacea
      Cetacea
      The order Cetacea includes the marine mammals commonly known as whales, dolphins, and porpoises. Cetus is Latin and is used in biological names to mean "whale"; its original meaning, "large sea animal", was more general. It comes from Ancient Greek , meaning "whale" or "any huge fish or sea...

      • Family Camelidae: camels (South America, Asia)
      • Family Suidae
        Suidae
        Suidae is the biological family to which pigs belong. In addition to numerous fossil species, up to sixteen extant species are currently recognized, classified into between four and eight genera...

        : pigs (Africa, Eurasia)
      • Family Tayassuidae: peccaries (New World)
      • Family Hippopotamidae
        Hippopotamidae
        Hippopotamuses are the members of the family Hippopotamidae. They are the only extant artiodactyls which walk on four toes on each foot.- Characteristics :...

        : hippos (Africa)
      • Family Balaenopteridae: rorquals and grey whales
      • Family Balaenidae
        Balaenidae
        Balaenidae is a family of mysticete whales that contains two living genera. Commonly called the right whales as it contains mainly right whale species...

        : right and bowhead whales
      • Family Physeteridae: sperm whales
      • Family Hyperoodontidae: beaked whales
      • Family Platanistidae: river dolphins
      • Family Delphinidae: dolphins
      • Family Pontoporiidae: La Plata River dolphin
      • Family Lipotidae: baiji
      • Family Iniidae
        Iniidae
        Iniidae is a family of river dolphins containing one living and three extinct genera.-Taxonomy:The family was described by John Edward Gray in 1846.Current classifications include a single living genera, Inia, with one species and three subspecies...

        : Amazon River dolphin
      • Family Monodontidae
        Monodontidae
        The cetacean family Monodontidae comprises two unusual whale species, the narwhal, in which the male has a long tusk, and the white beluga whale...

        : beluga and narwhal
      • Family Phocoenidae: porpoises
      • Family Tragulidae: mouse-deer (Africa, Asia)
      • Family Antilocapridae: pronghorn (North America)
      • Family Giraffidae
        Giraffidae
        The giraffids are ruminant artiodactyl mammals that share a common ancestor with deer and bovids. The biological family Giraffidae, once a diverse group spread throughout Eurasia and Africa, contains only two living members, the giraffe and the okapi. Both are confined to sub-saharan Africa: the...

        : giraffe and okapi (Africa)
      • Family Cervidae: deer (Holarctic, South America)
      • Family Moschidae: musk deer (Asia)
      • Family Bovidae: cattle, antelope, sheep, etc. (Africa, Holarctic)
    • Clade Pegasoferae
      Pegasoferae
      Pegasoferae is a proposed clade of mammals based on genomic research in molecular systematics by Nishihara, Hasegawa and Okada .To the surprise of the authors, their data led them to propose a clade that includes bats , carnivores such as cats and dogs , horses and other odd-toed ungulates and...

      • Order Chiroptera: bats (cosmopolitan)
        • Family Pteropodidae: flying foxes (Africa, Eurasia, Australia)
        • Family Rhinolophidae: Old World horseshoe and leaf-nosed bats (Old World)
        • Family Emballonuridae: sac-winged bats (southern continents)
        • Family Craseonycteridae: Kitti's hog-nosed bat (Thailand)
        • Family Rhinopomatidae
          Rhinopomatidae
          Mouse-tailed bats are a group of insectivorous bats of the family Rhinopomatidae with only three to five species, all contained in the single genus Rhinopoma. They are found in the Old World, from North Africa to Thailand and Sumatra, in arid and semi-arid regions, roosting in caves, houses and...

          : mouse-tailed bats (Africa, Southeast Asia)
        • Family Nycteridae
          Nycteridae
          Nycteridae is the family of slit-faced or hollow-faced bats. They are grouped in a single genus, Nycteris. The bats are found in East Malaysia, Indonesia and many parts of Africa....

          : slit-faced bats (Africa, Southeast Asia)
        • Family Megadermatidae
          Megadermatidae
          Megadermatidae, or False Vampire Bats, are a family of bats found from central Africa, eastwards through southern Asia, and into Australia. They are relatively large bats, ranging from 6.5 cm to 14 cm in head-body length. They have large eyes, very large ears and a prominent nose-leaf. They have a...

          : false vampire bats (Africa, Southeast Asia, Australia)
        • Family Phyllostomidae: leaf-nosed bats (South America)
        • Family Mormoopidae
          Mormoopidae
          The family Mormoopidae contains bats known generally as mustached bats, ghost-faced bats, and naked-backed bats. They are found in the Americas from the Southwestern United States to Southeastern Brazil....

          : leaf-chinned bats (South America)
        • Family Noctilionidae: fishing bats (South America)
        • Family Mystacinidae
          Mystacinidae
          Mystacinidae is a family of unusual bats, the New Zealand short-tailed bats. There is one living genus, Mystacina, with two extant species, one of which is believed to have become extinct in the 1960s. They are medium-sized bats, about in length, with grey, velvety fur.Mystacinids are the most...

          : short-tailed bats (New Zealand)
        • Family Molossidae: free-tailed bats (cosmopolitan)
        • Family Myzopodidae: sucker-footed bats (Madagascar)
        • Family Thyropteridae
          Thyropteridae
          Disc-winged bats are a small group of bats of the family Thyropteridae. They are found in Central and South America, usually in moist tropical rain forests. It is a very small family, consisting of a single genus with four species....

          : sucker-footed bats (South America)
        • Family Furipteridae
          Furipteridae
          Furipteridae is one of the families of bats. This family contains only two species, the Smokey Bat and the Thumbless Bat. Both are from Central and South America, and are closely related to the bats in the Natalidae and Thyropteridae families. They can be recognized by their reduced and...

          : smoky bats (South America)
        • Family Natalidae
          Natalidae
          The family Natalidae, or funnel-eared bats are found from Mexico to Brazil and the Caribbean islands. The family has three genera, Chilonatalus, Natalus and Nyctiellus. They are slender bats with unusually long tails and, as their name suggests, funnel-shaped ears. They are small, at only 3.5 to...

          : funnel-eared bats (South America)
        • Family Vespertilionidae: vesper bats (cosmopolitan)
      • Order Perissodactyla: odd-toed ungulates
        • Family Equidae
          Equidae
          Equidae is the taxonomic family of horses and related animals, including the extant horses, donkeys, and zebras, and many other species known only from fossils. All extant species are in the genus Equus...

          : horses, zebras, donkeys (Africa, West and Central Asia)
        • Family Tapiridae: tapirs (Central and South America, Southeast Asia)
        • Family Rhinocerotidae: rhinoceroses (Africa, Southeast Asia)
      • Clade Ferae
        Ferae
        Ferae is a clade of mammals, consisting of the orders Carnivora and Pholidota . Pangolins do not look much like carnivorans , and were thought to be the closest relatives of Xenarthra...

        • Order Pholidota
          • Family Manidae: pangolins, scaly anteaters (Africa, South Asia)
        • Order Carnivora
          Carnivora
          The diverse order Carnivora |Latin]] carō "flesh", + vorāre "to devour") includes over 260 species of placental mammals. Its members are formally referred to as carnivorans, while the word "carnivore" can refer to any meat-eating animal...

          : carnivorans (cosmopolitan)
          • Family Felidae
            Felidae
            Felidae is the biological family of the cats; a member of this family is called a felid. Felids are the strictest carnivores of the thirteen terrestrial families in the order Carnivora, although the three families of marine mammals comprising the superfamily pinnipedia are as carnivorous as the...

            : cats
          • Family Viverridae: civets, Asiatic palm civets
          • Family Herpestidae: mongooses
          • Family Hyaenidae: hyaenas, aardwolf
          • Family Canidae
            Canidae
            Canidae is the biological family of carnivorous and omnivorous mammals that includes wolves, foxes, jackals, coyotes, and domestic dogs. A member of this family is called a canid . The Canidae family is divided into two tribes: Canini and Vulpini...

            : dogs
          • Family Ursidae: bears
          • Family Otariidae: eared seals
          • Family Odobenidae
            Odobenidae
            Odobenidae is a family of Pinnipeds. The only living species is walrus.In the past, however, the group was much more diverse, and includes more than ten fossil genera.- Taxonomy :All genera, except Odobenus, are extinct.*Prototaria...

            : walrus
          • Family Phocidae: seals
          • Family Ailuridae
            Ailuridae
            Ailuridae is a family in the mammal order Carnivora. The family includes the Red Panda and its extinct relatives.-Classification history:...

            : red panda
          • Family Mephitidae: skunks
          • Family Mustelidae
            Mustelidae
            Mustelidae , commonly referred to as the weasel family, are a family of carnivorous mammals. Mustelids are diverse and the largest family in the order Carnivora, at least partly because in the past it has been a catch-all category for many early or poorly differentiated taxa...

            : weasels and relatives
          • Family Procyonidae
            Procyonidae
            Procyonidae is a New World family of the order Carnivora. It includes the raccoons, coatis, kinkajous, olingos, ringtails and cacomistles. Procyonids inhabit a wide range of environments, and are generally omnivorous.-Characteristics:...

            : ringtails, olingos, kinkajou, raccoons, coatis, red panda

Standardized textbook classification

A somewhat standardized classification system has been adopted by most current mammalogy
Mammalogy
In zoology, mammalogy is the study of mammals – a class of vertebrates with characteristics such as homeothermic metabolism, fur, four-chambered hearts, and complex nervous systems...

 classroom textbooks. The following taxonomy of extant and recently extinct mammals is taken from Vaughan et al. (2000). This approach emphasizes an initial split between egg-laying prototherians and live-bearing therians. The therians are further divided into the marsupial Metatheria and the "placental" Eutheria. No attempt is made here to further distinguish among the orders within these subclasses and infraclasses. This system also makes no note of the position of entirely fossil groups.

In this and later taxonomies listed here, families are merely listed under the order to which they belong. Please see the pages associated with specific orders to see more detailed relationships among families in that order.

Subclass Prototheria
Prototheria
Prototheria is a taxonomic group, or taxon, to which the order Monotremata belongs. It is conventionally ranked as a subclass within the mammals.Most of the animals in this group are extinct...

  • Order Monotremata
    • Family Tachyglossidae (echidnas)
    • Family Ornithorhynchidae
      Ornithorhynchidae
      Ornithorhynchidae is one of the two extant families in the order Monotremata, and contains the Platypus and its extinct relatives. The other family is the Tachyglossidae, or echidnas...

       (platypuses)

Subclass Theria
Theria
Theria is a subclass of mammals that give birth to live young without using a shelled egg, including both eutherians and metatherians . The only omitted extant mammal group is the egg-laying monotremes....

  • Infraclass Metatheria
    Metatheria
    Metatheria is a grouping within the animal class Mammalia. First proposed by Thomas Henry Huxley in 1880, it is nearly synonymous with the earlier taxon Marsupialia though it is slightly wider since it also contains the nearest fossil relatives of marsupial mammals.The earliest known...

     (marsupials and their nearest ancestors)
    • Order Didelphimorphia
      Didelphimorphia
      Opossums make up the largest order of marsupials in the Western Hemisphere, including 103 or more species in 19 genera. They are also commonly called possums, though that term technically refers to Australian fauna of the suborder Phalangeriformes. The Virginia opossum was the first animal to be...

      • Family Didelphidae (opossums, etc.)
    • Order Paucituberculata
      • Family Caenolestidae (shrew opossums)
    • Order Microbiotheria
      Microbiotheria
      The Monito del Monte is the only extant member of its family and the only surviving member of an ancient order, the Microbiotheria. The oldest microbiothere currently recognised is Khasia cordillerensis, based on fossil teeth from Early Palaeocene deposits at Tiupampa, Bolivia...

      • Family Microbiotheriidae (monito del montes)
    • Order Dasyuromorphia
      Dasyuromorphia
      The order Dasyuromorphia comprises most of the Australian carnivorous marsupials, including quolls, dunnarts, the numbat, the Tasmanian devil, and the recently extinct thylacine...

       (most carnivorous marsupials)
      • Family Thylacinidae
        Thylacinidae
        The animals in the Thylacinidae family were all carnivorous marsupials from the order Dasyuromorphia. The only recent member was the Thylacine , which became extinct in 1936...

         (Tasmanian tigers)
      • Family Myrmecobiidae (numbats)
      • Family Dasyuridae
        Dasyuridae
        Dasyuridae is a family of marsupials native to Australia and New Guinea, including 61 species divided into 15 genera. Many are small and mouse-like, giving them the misnomer marsupial mice, but the group also includes the cat-sized quolls, as well as the Tasmanian Devil...

         (Tasmanian devils, quolls, dunnarts, planigale, etc.)
    • Order Peramelemorphia
      Peramelemorphia
      The order Peramelemorphia includes the bandicoots and bilbies: it equates approximately to the mainstream of marsupial omnivores...

       (bandicoots, bilbies, etc.)
      • Family Peramelidae
        Peramelidae
        Peramelidae is the family of marsupials that contains all of the extant bandicoots. One known extinct species of bandicoot, the Pig-footed Bandicoot, was so different than the other species that it was recently moved into its own family. There are four described fossil Peramelids...

      • Family Peroryctidae
    • Order Notoryctemorphia (marsupial moles)
      • Family Notoryctidae
    • Order Diprotodontia
      Diprotodontia
      Diprotodontia is a large order of about 120 marsupial mammals including the kangaroos, wallabies, possums, koala, wombats, and many others. Extinct diprotodonts include the rhinoceros-sized Diprotodon, and Thylacoleo, the so-called "marsupial lion"....

      • Family Phascolarctidae
        Phascolarctidae
        Phascolarctidae is a family of marsupials of the order Diprotodontia, consisting of only one extant species, the Koala, six well known fossil species, with another 5 less well known fossil species, and 2 fossil species whose taxonomy is debatable but is put in this group...

         (koalas)
      • Family Vombatidae (wombats)
      • Family Phalangeridae
        Phalangeridae
        Phalangeridae is a family of nocturnal marsupials native to Australia and New Guinea, including the cuscuses, brushtail possums, and their close relatives...

         (brushtail possums and cuscuses)
      • Family Potoroidae
        Potoroidae
        The marsupial family Potoroidae includes the bettongs, potoroos, and two of the rat-kangaroos. All are rabbit-sized, brown, jumping marsupials and resemble a large rodent or a very small wallaby.- Characteristics :...

         (bettongs, potaroos and rat kangaroos)
      • Family Macropodidae (kangaroos, wallabies, etc.)
      • Family Burramyidae (pygmy possums)
      • Family Pseudocheiridae
        Pseudocheiridae
        Pseudocheiridae is a family of arboreal marsupials containing 17 extant species of ringtailed possums and close relatives. They are found in forested areas and shrublands throughout Australia and New Guinea.-Characteristics:...

         (ringtailed possums, etc.)
      • Family Petauridae
        Petauridae
        The family Petauridae includes 11 medium-sized possum species: four striped possums, the six species wrist-winged gliders in genus Petaurus, and Leadbeater's Possum which has only vestigal gliding membranes...

         (Striped Possum
        Striped Possum
        The Striped Possum is a member of the Petauridae family, one of the marsupial families. The species is black with three white stripes running head to tail, and its head has white stripes that form a 'Y' shape...

        , Leadbeater's Possum
        Leadbeater's Possum
        Leadbeater's Possum is an endangered possum restricted to small pockets of remaining old growth mountain ash forests in the central highlands of Victoria north-east of Melbourne...

        , Yellow-bellied Glider
        Yellow-bellied Glider
        The Yellow-bellied Glider is an arboreal and nocturnal gliding possum that lives in a narrow range of native eucalypt forests down eastern Australia, reaching from northern Queensland to Victoria.-Habitat:...

        , Sugar Glider
        Sugar Glider
        The sugar glider is a small gliding possum originating from the marsupial family.The sugar glider is native to eastern and northern mainland Australia and is also native to New Guinea and the Bismarck Archipelago.- Habitat :Sugar gliders can be found all throughout the northern and eastern parts of...

        , Mahogany Glider
        Mahogany Glider
        The mahogany glider is an endangered gliding possum native to a small region of coastal Queensland.-Appearance:A nocturnal arboreal marsupial, the mahogany glider closely resembles the sugar glider, the squirrel glider and the yellow-bellied glider., but is noticeably larger than any of its...

         and Squirrel Glider
        Squirrel Glider
        The Squirrel Glider is a nocturnal gliding possum, one of the wrist-winged gliders of the genus Petaurus.-Habitat:...

        )
      • Family Tarsipedidae (honey possum)
      • Family Acrobatidae
        Acrobatidae
        Acrobatidae is a small family of gliding marsupials containing two genera, each with a single species, the Feathertail Glider from Australia and Feather-tailed Possum from New Guinea....

         (Feathertail Glider
        Feathertail Glider
        The Feathertail Glider , also known as the Pygmy Gliding Possum, Pygmy Glider, Pygmy Phalanger, Flying Phalanger and Flying Mouse, is the world's smallest gliding possum and is named for its long feather-shaped tail. Although only the size of a very small mouse , it can leap and glide up to 25 metres...

         and Feather-tailed Possum
        Feather-tailed Possum
        The Feather-tailed Possum is a species of marsupial in the Acrobatidae family. It is found in West Papua, Indonesia and Papua New Guinea.It is the only species in the genus Distoechurus....

        )
  • Infraclass Eutheria
    Eutheria
    Eutheria is a group of mammals consisting of placental mammals plus all extinct mammals that are more closely related to living placentals than to living marsupials . They are distinguished from noneutherians by various features of the feet, ankles, jaws and teeth...

    • Order Xenarthra
      Xenarthra
      The superorder Xenarthra is a group of placental mammals , existent today only in the Americas and represented by anteaters, tree sloths, and armadillos. The origins of the order can be traced back as far as the Paleogene in South America...

      • Family Bradypodidae
      • Family Megalonychidae
        Megalonychidae
        Megalonychidae is a group of sloths including the extinct Megalonyx and the living two toed sloths. Megalonychids first appeared in the early Oligocene, about 35 million years ago, in southern Argentina , and spread as far as the Antilles by the early Miocene...

      • Family Dasypodidae
      • Family Myrmecophagidae
        Myrmecophagidae
        Myrmecophagidae is a family of anteaters, the name being derived from the Ancient Greek words for 'ant' and 'eat' . Myrmecophagids are native to Central and South America, from southern Mexico to northern Argentina. There are 2 genera and 3 species in the family, consisting of the Giant Anteater,...

    • Order Insectivora
      Insectivora
      The order Insectivora is a now-abandoned biological grouping within the class of mammals...

      • Family Solenodontidae
        Solenodontidae
        Solenodons are venomous, nocturnal, burrowing, insectivorous mammals belonging to the family Solenodontidae. Only one genus, Solenodon, is known, although a few other genera were erected at one time and are now regarded as junior synonyms...

      • Family Nesophontidae
      • Family Tenrecidae
        Tenrecidae
        Tenrecidae is a family of mammals found on Madagascar and parts of Africa. Tenrecs are widely diverse, resembling hedgehogs, shrews, opossums, mice and even otters, as a result of convergent evolution. They occupy aquatic, arboreal, terrestrial and fossorial environments...

      • Family Chrysochloridae
      • Family Erinaceidae
        Erinaceidae
        Erinaceidae is the only living family in the order Erinaceomorpha, which has recently been subsumed with Soricomorpha into the order Eulipotyphla...

      • Family Soricidae
      • Family Talpidae
        Talpidae
        The family Talpidae includes the moles, shrew moles, desmans, and other intermediate forms of small insectivorous mammals of the order Soricomorpha...

    • Order Scandentia
      • Family Tupaiidae
        Tupaiidae
        Tupaiidae is one of two families of treeshrews, the other family being Ptilocercidae. It contains 4 genera and 19 species.-Taxonomy:*Order: Scandentia** Family Tupaiidae*** Genus Anathana**** Madras Treeshrew, Anathana ellioti...

    • Order Dermoptera
      • Family Cynocephalidae
    • Order Chiroptera
      • Family Pteropodidae
      • Family Emballonuridae
      • Family Craseonycteridae
      • Family Rhinopomatidae
        Rhinopomatidae
        Mouse-tailed bats are a group of insectivorous bats of the family Rhinopomatidae with only three to five species, all contained in the single genus Rhinopoma. They are found in the Old World, from North Africa to Thailand and Sumatra, in arid and semi-arid regions, roosting in caves, houses and...

      • Family Nycteridae
        Nycteridae
        Nycteridae is the family of slit-faced or hollow-faced bats. They are grouped in a single genus, Nycteris. The bats are found in East Malaysia, Indonesia and many parts of Africa....

      • Family Megadermatidae
        Megadermatidae
        Megadermatidae, or False Vampire Bats, are a family of bats found from central Africa, eastwards through southern Asia, and into Australia. They are relatively large bats, ranging from 6.5 cm to 14 cm in head-body length. They have large eyes, very large ears and a prominent nose-leaf. They have a...

      • Family Rhinolophidae
      • Family Phyllostomidae
      • Family Mormoopidae
        Mormoopidae
        The family Mormoopidae contains bats known generally as mustached bats, ghost-faced bats, and naked-backed bats. They are found in the Americas from the Southwestern United States to Southeastern Brazil....

      • Family Noctilionidae
      • Family Mystacinidae
        Mystacinidae
        Mystacinidae is a family of unusual bats, the New Zealand short-tailed bats. There is one living genus, Mystacina, with two extant species, one of which is believed to have become extinct in the 1960s. They are medium-sized bats, about in length, with grey, velvety fur.Mystacinids are the most...

      • Family Molossidae
      • Family Myzopodidae
      • Family Thyropteridae
        Thyropteridae
        Disc-winged bats are a small group of bats of the family Thyropteridae. They are found in Central and South America, usually in moist tropical rain forests. It is a very small family, consisting of a single genus with four species....

      • Family Furipteridae
        Furipteridae
        Furipteridae is one of the families of bats. This family contains only two species, the Smokey Bat and the Thumbless Bat. Both are from Central and South America, and are closely related to the bats in the Natalidae and Thyropteridae families. They can be recognized by their reduced and...

      • Family Natalidae
        Natalidae
        The family Natalidae, or funnel-eared bats are found from Mexico to Brazil and the Caribbean islands. The family has three genera, Chilonatalus, Natalus and Nyctiellus. They are slender bats with unusually long tails and, as their name suggests, funnel-shaped ears. They are small, at only 3.5 to...

      • Family Vespertilionidae
    • Order Primates
      • Family Daubentoniidae
      • Family Lemuridae
        Lemuridae
        Lemuridae is a family of prosimian primates native to Madagascar, and one of five families commonly known as lemurs. These animals were thought to be the evolutionary predecessors of monkeys and apes, but this is no longer considered correct...

      • Family Lepilemuridae
      • Family Galagidae
      • Family Lorisidae
        Lorisidae
        Lorisidae is a family of strepsirrhine primates. The lorisids are all slim arboreal animals and include the lorises, pottos and angwantibos. Lorisids live in tropical, central Africa as well as in south and southeast Asia....

      • Family Cheirogaleidae
        Cheirogaleidae
        Cheirogaleidae is the family of strepsirrhine primates that contains the various dwarf and mouse lemurs. Like all other lemurs, cheirogaleids live exclusively on the island of Madagascar.-Characteristics:...

      • Family Indriidae
        Indriidae
        The Indriidae are a family of strepsirrhine primates. They are medium to large sized lemurs with only four teeth in the toothcomb instead of the usual six...

      • Family Tarsiidae
      • Family Cercopithecidae
      • Family Hominidae
        Hominidae
        The Hominidae or include them .), as the term is used here, form a taxonomic family, including four extant genera: chimpanzees , gorillas , humans , and orangutans ....

      • Family Hylobatidae
      • Family Callitrichidae
      • Family Cebidae
        Cebidae
        The Cebidae is one of the five families of New World monkeys now recognised. It includes the capuchin monkeys and squirrel monkeys. These species are found throughout tropical and subtropical South and Central America.-Characteristics:...

    • Order Carnivora
      Carnivora
      The diverse order Carnivora |Latin]] carō "flesh", + vorāre "to devour") includes over 260 species of placental mammals. Its members are formally referred to as carnivorans, while the word "carnivore" can refer to any meat-eating animal...

      • Family Felidae
        Felidae
        Felidae is the biological family of the cats; a member of this family is called a felid. Felids are the strictest carnivores of the thirteen terrestrial families in the order Carnivora, although the three families of marine mammals comprising the superfamily pinnipedia are as carnivorous as the...

      • Family Viverridae
      • Family Herpestidae
      • Family Hyaenidae
      • Family Canidae
        Canidae
        Canidae is the biological family of carnivorous and omnivorous mammals that includes wolves, foxes, jackals, coyotes, and domestic dogs. A member of this family is called a canid . The Canidae family is divided into two tribes: Canini and Vulpini...

      • Family Ursidae
      • Family Otariidae
      • Family Phocidae
      • Family Odobenidae
        Odobenidae
        Odobenidae is a family of Pinnipeds. The only living species is walrus.In the past, however, the group was much more diverse, and includes more than ten fossil genera.- Taxonomy :All genera, except Odobenus, are extinct.*Prototaria...

      • Family Mustelidae
        Mustelidae
        Mustelidae , commonly referred to as the weasel family, are a family of carnivorous mammals. Mustelids are diverse and the largest family in the order Carnivora, at least partly because in the past it has been a catch-all category for many early or poorly differentiated taxa...

      • Family Procyonidae
        Procyonidae
        Procyonidae is a New World family of the order Carnivora. It includes the raccoons, coatis, kinkajous, olingos, ringtails and cacomistles. Procyonids inhabit a wide range of environments, and are generally omnivorous.-Characteristics:...

    • Order Cetacea
      Cetacea
      The order Cetacea includes the marine mammals commonly known as whales, dolphins, and porpoises. Cetus is Latin and is used in biological names to mean "whale"; its original meaning, "large sea animal", was more general. It comes from Ancient Greek , meaning "whale" or "any huge fish or sea...

      • Family Balaenopteridae
      • Family Eschrichtiidae
        Eschrichtiidae
        Eschrichtiidae is a family of baleen whales in the suborder Mysticeti.At least five genera are recognised, but only a single species from one genus is still alive, the gray whale, Eschrichtius robustus....

      • Family Balaenidae
        Balaenidae
        Balaenidae is a family of mysticete whales that contains two living genera. Commonly called the right whales as it contains mainly right whale species...

      • Family Neobalaenidae
      • Family Physeteridae
      • Family Ziphiidae
      • Family Platanistidae
      • Family Delphinidae
      • Family Monodontidae
        Monodontidae
        The cetacean family Monodontidae comprises two unusual whale species, the narwhal, in which the male has a long tusk, and the white beluga whale...

      • Family Phocoenidae
    • Order Sirenia
      Sirenia
      Sirenia is an order of fully aquatic, herbivorous mammals that inhabit swamps, rivers, estuaries, marine wetlands, and coastal marine waters. Four species are living, in two families and genera. These are the dugong and manatees...

      • Family Dugongidae
        Dugongidae
        Dugongidae is a family in the order of Sirenia.The family has one surviving species, the Dugong , one recently extinct species, the Steller's Sea Cow , and a number of extinct genera known from the fossil record....

      • Family Trichechidae
    • Order Proboscidea
      Proboscidea
      Proboscidea is a taxonomic order containing one living family, Elephantidae, and several extinct families. This order was first described by J. Illiger in 1881 and encompasses the trunked mammals...

      • Family Elephantidae
        Elephantidae
        Elephantidae is a taxonomic family, collectively elephants and mammoths. These are terrestrial large mammals with a trunk and tusks. Most genera and species in the family are extinct...

    • Order Perissodactyla
      • Family Equidae
        Equidae
        Equidae is the taxonomic family of horses and related animals, including the extant horses, donkeys, and zebras, and many other species known only from fossils. All extant species are in the genus Equus...

      • Family Tapiridae
      • Family Rhinocerotidae
    • Order Hyracoidea
      • Family Procaviidae
    • Order Tubulidentata
      • Family Orycteropodidae
        Orycteropodidae
        Orycteropodidae is a family of afrotherian mammals. Although there are many fossil species, the only species surviving today is the aardvark, Orycteropus afer. Orycteropodidae is recognized as the only family within the order Tubulidentata, so the two are effectively synonyms.The family arose in...

    • Order Artiodactyla
      • Family Suidae
        Suidae
        Suidae is the biological family to which pigs belong. In addition to numerous fossil species, up to sixteen extant species are currently recognized, classified into between four and eight genera...

      • Family Tayassuidae
      • Family Hippopotamidae
        Hippopotamidae
        Hippopotamuses are the members of the family Hippopotamidae. They are the only extant artiodactyls which walk on four toes on each foot.- Characteristics :...

      • Family Camelidae
      • Family Tragulidae
      • Family Giraffidae
        Giraffidae
        The giraffids are ruminant artiodactyl mammals that share a common ancestor with deer and bovids. The biological family Giraffidae, once a diverse group spread throughout Eurasia and Africa, contains only two living members, the giraffe and the okapi. Both are confined to sub-saharan Africa: the...

      • Family Moschidae
      • Family Cervidae
      • Family Antilocapridae
      • Family Bovidae
    • Order Pholidota
      • Family Manidae
    • Order Rodentia
      • Family Aplodontiidae
      • Family Sciuridae
      • Family Castoridae
        Castoridae
        The family Castoridae contains the two living species of beaver and their fossil relatives. This was once a highly diverse group of rodents, but is now restricted to a single genus, Castor.- Characteristics :...

      • Family Geomyidae
      • Family Heteromyidae
        Heteromyidae
        The family of rodents that include kangaroo rats, kangaroo mice and rock pocket mice is the Heteromyidae family. Most heteromyids live in complex burrows within the deserts and grasslands of western North America, though species within the Heteromys and Liomys genera are also found in forests and...

      • Family Dipodidae
        Dipodidae
        The Dipodidae, or dipodids, are a family of rodents found across the northern hemisphere. This family includes over 50 species among the 16 genera....

      • Family Muridae
        Muroidea
        Muroidea is a large superfamily of rodents. It includes hamsters, gerbils, true mice and rats, and many other relatives. They occupy a vast variety of habitats on every continent except Antarctica. Some authorities have placed all members of this group into a single family, Muridae, due to...

      • Family Anomaluridae
      • Family Pedetidae
        Pedetidae
        Pedetidae is a family of mammals from the rodent order. The two living species, the springhares, are distributed throughout much of southern Africa and also around Kenya, Tanzania and Uganda. Fossils have been found as far north as Turkey. Together with the anomalures, Pedetidae forms the suborder...

      • Family Ctenodactylidae
      • Family Myoxidae
      • Family Bathyergidae
      • Family Hystricidae
      • Family Petromuridae
      • Family Thryonomyidae
      • Family Erethizontidae
      • Family Chinchillidae
        Chinchillidae
        The family Chinchillidae contains the chinchillas, viscachas, and their fossil relatives. They are restricted to southern and western South America, often in association with the Andes. They are large rodents, weighing from to , with strong hind legs and large ears...

      • Family Dinomyidae
        Dinomyidae
        Dinomyidae was once a very speciose group of South American hystricognath rodent, but now contains only a single living species, the Pacarana. The Dinomyidae included among its ranks the largest rodents known to date, the bison-sized Josephoartigasia monesi and the smaller Josephoartigasia magna...

      • Family Caviidae
        Caviidae
        The cavy family is a family of rodents native to South America, and including the domestic guinea pig, wild cavies, and the capybara, among other animals...

      • Family Hydrochaeridae
      • Family Dasyproctidae
        Dasyproctidae
        Dasyproctidae is a family of large South American rodents, comprising the agoutis and acouchis. Their fur is a reddish or dark colour above, with a paler underside. They are herbivorous, often feeding on ripe fruit that falls from trees...

      • Family Agoutidae
      • Family Ctenomyidae
      • Family Octodontidae
        Octodontidae
        The Octodontidae are a family of rodents, restricted to south-western South America. Thirteen species of octodontid are recognised, arranged in nine genera. The best known species is the Degu, Octodon degus....

      • Family Abrocomidae
      • Family Echimyidae
      • Family Capromyidae
      • Family Heptaxodontidae
      • Family Myocastoridae
    • Order Lagomorpha
      Lagomorpha
      The lagomorphs are the members of the taxonomic order Lagomorpha, of which there are two living families, the Leporidae , and the Ochotonidae...

      • Family Ochotonidae
      • Family Leporidae
        Leporidae
        Leporids are the approximately 50 species of rabbits and hares which form the family Leporidae. The leporids, together with the pikas, constitute the mammalian order Lagomorpha. Leporids differ from pikas in having short furry tails, and elongated ears and hind legs...

    • Order Macroscelidea
      • Family Macroscelididae

McKenna/Bell classification

In 1997, the mammals were comprehensively revised by Malcolm C. McKenna and Susan K. Bell, which has resulted in the "McKenna/Bell classification".

McKenna and Bell, Classification of Mammals: Above the species level, (McKenna & Bell, 1997) is the most comprehensive work to date on the systematics, relationships, and occurrences of all mammal taxa, living and extinct, down through the rank of genus. The new McKenna/Bell classification was quickly accepted by paleontologists. The authors work together as paleontologists at the American Museum of Natural History
American Museum of Natural History
The American Museum of Natural History , located on the Upper West Side of Manhattan in New York City, United States, is one of the largest and most celebrated museums in the world...

, New York. McKenna inherited the project from Simpson and, with Bell, constructed a completely updated hierarchical system, covering living and extinct taxa that reflects the historical genealogy of Mammalia.

The McKenna/Bell hierarchical listing of all of the terms used for mammal groups above the species includes extinct mammals as well as modern groups, and introduces some fine distinctions such as legions and sublegions
Legion (biology)
The legion, in biological taxonomy, is a non-obligatory taxonomic rank within the Linnaean hierarchy which is subordinate to the class but superordinate to the cohort...

 and (ranks which fall between classes and orders) that are likely to be glossed over by the layman.

The published re-classification forms both a comprehensive and authoritative record of approved names and classifications and a list of invalid names.

Click on the highlighted link for a table comparing the traditional and the new McKenna/Bell classifications of mammals

Extinct groups are represented by †.

Subclass Prototheria
Prototheria
Prototheria is a taxonomic group, or taxon, to which the order Monotremata belongs. It is conventionally ranked as a subclass within the mammals.Most of the animals in this group are extinct...

(monotremes)
  • Order Platypoda
    Platypoda
    Platypoda is a suborder of the monotremes; it includes three families and a single living species, the Platypus. All others are extinct....

    : platypuses
    • Family Ornithorhynchidae
      Ornithorhynchidae
      Ornithorhynchidae is one of the two extant families in the order Monotremata, and contains the Platypus and its extinct relatives. The other family is the Tachyglossidae, or echidnas...

      : platypuses
  • Order Tachyglossa: echidnas (spiny anteaters)
    • Family Tachyglossidae: echidnas

Subclass Theriiformes

  • Infraclass †Allotheria
    Allotheria
    Allotheria was a branch of successful Mesozoic mammals. The most important characteristic was the presence of lower molariform teeth equipped with two longitudinal rows of cusps...

    • Order †Multituberculata
      Multituberculata
      The Multituberculata were a group of rodent-like mammals that existed for approximately one hundred and twenty million years—the longest fossil history of any mammal lineage—but were eventually outcompeted by rodents, becoming extinct during the early Oligocene. At least 200 species are...

      : multituberculates
      • Family †Plagiaulacidae
        Plagiaulacidae
        Plagiaulacidae is a family of fossil mammals within the order Multituberculata. Remains are known from the Upper Jurassic of North America through the Lower Cretaceous of Europe...

      • Family †Bolodontidae
      • Family †Hahnodontidae
      • Family †Albionbaataridae
        Albionbaataridae
        Albionbaataridae is a family of small, extinct mammals within the order Multituberculata. Fossil remains are known from the Upper Jurassic and Lower Cretaceous of Europe and Asia. These herbivores lived their obscure lives during the Mesozoic, also known as the "age of the dinosaurs." They were...

      • Family †Arginbaataridae
      • Family †Kogaionidae
        Kogaionidae
        Kogaionidae is a family of fossil mammals within the extinct order Multituberculata. Representatives are known from the upper Cretaceous and the Paleocene of Europe. This family is part of the suborder Cimolodonta. Other than that, their systematic relationships are hard to define.These small...

      • Family †Sloanbaataridae
        Sloanbaataridae
        Sloanbaataridae is a family of fossil mammals within the extinct order Multituberculata. Remains are known from the Upper Cretaceous of Mongolia. These small herbivores lived during the "age of the dinosaurs". This family is part of the suborder Cimolodonta. The family Sloanbaataridae was named by...

      • Family †Cimolodontidae
        Cimolodontidae
        Cimolodontidae is a family of fossil mammals within the extinct order Multituberculata. Representatives are known from the Upper Cretaceous and Paleocene of North America. There is some doubt as to whether Cimolodon is within this taxon. If not, the name of the family would still be valid...

      • Family †Ptilodontidae
        Ptilodontidae
        Ptilodontidae is a family of primitive mammals within the extinct order Multituberculata. Representatives are known from the Upper Cretaceous and Paleocene of North America....

      • Family †Cimolomyidae
        Cimolomyidae
        Cimolomyidae is a family of fossil mammal within the extinct order Multituberculata. Representatives are known from the Upper Cretaceous and the Paleocene of North America and perhaps Mongolia. The family is part of the suborder Cimolodonta. Other than that, their systematic relationships are hard...

      • Family †Eucosmodontidae
        Eucosmodontidae
        Eucosmodontidae is a poorly preserved family of fossil mammals within the extinct order Multituberculata. Representatives are known from strata dating from the Upper Cretaceous through the Lower Eocene of North America, as well as the Paleocene to Eocene of Europe. The family is part of the...

      • Family †Taeniolabididae
      • Family †Ferugliotheriidae
        Ferugliotheriidae
        Ferugliotheriidae is one of two known families in the order Gondwanatheria, an enigmatic group of extinct mammals. Gondwanatheres have been classified as a group of uncertain affinities or as members of Multituberculata, a major extinct mammalian order. The best-known representative of...

      • Family †Sudamericidae
        Sudamericidae
        Sudamericidae is a family of gondwanathere mammals that lived during the late Cretaceous to Eocene. Its members include Lavanify from the Cretaceous of Madagascar, Bharattherium from the Cretaceous of India, Gondwanatherium from the Cretaceous of Argentina, Sudamerica from the Paleocene of...

  • Infraclass †Triconodonta
    Triconodonta
    Triconodonta is the generic name for a group of early mammals which were close relatives of the ancestors of all present-day mammals. Triconodonts lived between the Triassic and the Cretaceous. They are one of the groups that can be classified as mammals by any definition...

    • Family †Austrotriconodontidae
    • Family †Amphilestidae
      Amphilestidae
      Amphilestidae is a family of Late Jurassic mammals from England....

    • Family †Triconodontidae
      Triconodontidae
      Triconodontidae is an extinct family of actively mobile mammal, endemic to what would be North America, Europe, and Africa during the Jurassic through Cretaceous periods from 155.7—70.6 mya, existing for approximately .-Taxonomy:...

  • Infraclass Holotheria
    • Family †Chronoperatidae
    • Superlegion †Kuehneotheria
      • Family †Kuehneotheriidae
        Kuehneotheriidae
        Kuehneotheriidae is a clade within Symmetrodonta and was created to embrace Kuehneotherium and Woutersia, which lived in Europe in the late Triassic and early Jurassic...

      • Family †Woutersiidae
    • Superlegion Trechnotheria
      Trechnotheria
      Trechnotheria is a group of mammals that includes the therians and some fossil mammals from the Mesozoic Era. In the Jurassic through Cretaceous periods, the group was endemic to what would be Asia and Africa...

      • Legion †Symmetrodonta
        Symmetrodonta
        Symmetrodonta is a basal group of Mesozoic mammals characterized by the triangular aspect of the molars when viewed from above and the absence of a well-developed talonid. The traditional group of symmetrodonts ranges in age from the latest Triassic to the Late Cretaceous. One species,...

        • Family †Shuotheriidae
          Shuotheriidae
          Shuotheriidae is the sole family within the order Shuotheridia, it includes Pseudotribos and Shuotherium.-Further reading:Zofia Kielan-Jaworowska, Richard L. Cifelli, and Zhe-Xi Luo, Mammals from the Age of Dinosaurs: Origins, Evolution, and Structure , 214-215....

        • Order †Amphidontoidea
          • Family †Amphidontidae
            Amphidontidae
            The Amphidontidae are a family of extinct mammals from the Early Creataceous, belonging to the triconodonts. It contains most of the species previously belonged to Amphilestidae.- Phylogeny :...

        • Order †Spalacotherioidea
          • Family †Tinodontidae
            Tinodontidae
            Tinodontidae is an extinct family of actively mobile mammal, endemic to what would now be North America, Asia, Europe, and Africa during the Jurassic and Cretaceous periods.-Taxonomy:Tinodontidae...

          • Family †Spalacotheriidae
          • Family †Barbereniidae
      • Legion Cladotheria
        Cladotheria
        Cladotheria is a group of mammals that is defined as including the ancestor of Dryolestoidea, Peramuridae and Zatheria .-External links:* * -Further reading:Zofia Kielan-Jaworowska, Richard L...

        • Sublegion †Dryolestoidea
          Dryolestoidea
          Dryolestoidea is an extinct clade of Mesozoic mammals that only contains two orders. It has been suggested that this group contained the ancestors of modern therian mammals. They are mostly represented by teeth, fragmented dentaries and parts of the rostrum. The Jurassic forms retained a...

          • Order †Dryolestida
            Dryolestida
            Dryolestida is an extinct order of mammals known from the Jurassic to Tertiary. It has been suggested that these mammals are either the possible ancestors of therian mammals or an offshoot from the same evolutionary line. It is also believed that they developed a fully mammalian jaw and also had...

            • Family †Dryolestidae
              Dryolestidae
              Dryolestidae was an abundant and diverse group of Mesozoic mammals. These mammals were different from their relatives by having the following two characteristics:*Their upper and lower molars were shortened mesiodistally and widened labiolingually....

            • Family †Paurodontidae
              Paurodontidae
              Paurodontidae is a family of Late Jurassic to Early Cretaceous mammals in the order Dryolestida. Remains of paurodontids have been found in the USA, Britain, Portugal, and Tanzania....

            • Family †Donodontidae
            • Family †Mesungulatidae
            • Family †Reigitheriidae
            • Family †Brandoniidae
          • Order †Amphitheriida
            Amphitheriida
            Amphitheriida is an order of mesozoic mammals restricted to the Middle Jurassic of Britain. They were closely related to the Dryolestids but possessed five molars instead of the usual four in Dryolestida,...

            • Family †Amphitheriidae
        • Sublegion Zatheria
          Zatheria
          Zatheria is a group of mammals that is defined as including the ancestor of Arguitheriidae, Arguimuridae, Vincelestidae, Peramuridae and Tribosphenida .-External links:* *...

          • Family †Arguitheriidae
          • Family †Arguimuridae
          • Family †Vincelestidae
          • Infralegion †Peramura
            • Family †Peramuridae
              Peramuridae
              The family Peramuridae is a possible ancestor of early therians. The only certain representative lived in the Late Jurassic and Early Cretaceous.-References:*...

          • Infralegion Tribosphenida
            Tribosphenida
            Tribosphenida is a group of mammals that is defined as including the ancestor of Hypomylos, Necrolestidae, Aegialodontia and supercohort Theria .-External links:* * * -Further reading:...

            • Family †Necrolestidae
            • Supercohort †Aegialodontia
              • Family †Aegialodontidae
            • Supercohort Theria
              Theria
              Theria is a subclass of mammals that give birth to live young without using a shelled egg, including both eutherians and metatherians . The only omitted extant mammal group is the egg-laying monotremes....

              : therian mammals
              • Family †Pappotheriidae
              • Family †Holoclemensiidae
              • Family †Kermackiidae
              • Family †Endotheriidae
              • Family †Picopsidae
              • Family †Potamotelsidae
              • Family †Plicatodontidae
              • Order †Deltatheroida
                Deltatheroida
                Deltatheroida is an extinct group of basal metatherians that lived in the Cretaceous and were closely related to marsupials. Their fossils are restricted to Central Asia and North America...

                • Family †Deltatheridiidae
                • Family †Deltatheroididae
              • Order †Asiadelphia
                Asiadelphia
                Asiadelphia is an order of Cretaceous Metatherians. Different from the Ameridelphia, they lacked a prominent distolateral process on the scaphoid, and possessed a more slender fibula. The masseteric fossa is deeper in this group than the true Marsupials.-Further reading:Zofia Kielan-Jaworowska,...

                • Family †Asiatheriidae
              • Cohort Marsupialia: marsupials
                • Family †Yingabalanaridae
                • Family †Stagodontidae
                • Family †Pediomyidae
                • Magnorder Australidelphia
                  Australidelphia
                  Australidelphia is the superorder that contains roughly three-quarters of all marsupials, including all those native to Australasia and a single species from South America...

                  • Superorder Microbiotheria
                    Microbiotheria
                    The Monito del Monte is the only extant member of its family and the only surviving member of an ancient order, the Microbiotheria. The oldest microbiothere currently recognised is Khasia cordillerensis, based on fossil teeth from Early Palaeocene deposits at Tiupampa, Bolivia...

                    • Family Microbiotheriidae: monito del monte
                  • Superorder Eometatheria
                    • Order †Yalkaparidontia
                      • Family †Yalkaparidontidae
                    • Order Notoryctemorphia: marsupial moles
                      • Family Notoryctidae: marsupial moles
                    • Grandorder Dasyuromorphia
                      Dasyuromorphia
                      The order Dasyuromorphia comprises most of the Australian carnivorous marsupials, including quolls, dunnarts, the numbat, the Tasmanian devil, and the recently extinct thylacine...

                      : marsupial carnivores
                      • Family †Thylacinidae
                        Thylacinidae
                        The animals in the Thylacinidae family were all carnivorous marsupials from the order Dasyuromorphia. The only recent member was the Thylacine , which became extinct in 1936...

                        : recently extinct Tasmanian tiger and relatives
                      • Family Dasyuridae
                        Dasyuridae
                        Dasyuridae is a family of marsupials native to Australia and New Guinea, including 61 species divided into 15 genera. Many are small and mouse-like, giving them the misnomer marsupial mice, but the group also includes the cat-sized quolls, as well as the Tasmanian Devil...

                        : Tasmanian devil, quolls, etc.
                      • Family Myrmecobiidae: numbat
                    • Grandorder Syndactyli: syndactylous marsupials
                      • Order Peramelia: bandicoots
                        • Family Peramelidae
                          Peramelidae
                          Peramelidae is the family of marsupials that contains all of the extant bandicoots. One known extinct species of bandicoot, the Pig-footed Bandicoot, was so different than the other species that it was recently moved into its own family. There are four described fossil Peramelids...

                        • Family Peroryctidae
                      • Order Diprotodontia
                        Diprotodontia
                        Diprotodontia is a large order of about 120 marsupial mammals including the kangaroos, wallabies, possums, koala, wombats, and many others. Extinct diprotodonts include the rhinoceros-sized Diprotodon, and Thylacoleo, the so-called "marsupial lion"....

                        • Family †Palorchestidae
                          Palorchestidae
                          The family Palorchestidae contains four genera with eight species described. All species are extinct.*Propalorchestes **P. novaculocephalus **P. painei *Ngapakaldia...

                        • Family †Wynardiidae
                        • Family †Thylacoleonidae
                          Thylacoleonidae
                          Thylacoleonidae is a family of extinct meat-eating marsupials from Australia, referred to as marsupial lions. The best known is Thylacoleo carnifex, also called the Marsupial Lion...

                        • Family Tarsipedidae: honey possum
                        • Family †Ilariidae
                          Ilariidae
                          The family Ilariidae consists of 3 species of extinct marsupial in two genera. They are all found in the middle tertiary assemblage of South Australia. Closely related to Koobor of family Phascolarctidae, which was found in Hamilton Victoria. I. illumidens is the best preserved representative of...

                        • Family †Diprotodontidae
                          Diprotodontidae
                          Diprotodontidae is an extinct family of large, actively mobile marsupial, endemic to what would be Australia, during the Oligocene through Pleistocene periods from 28.4 mya—11,000 years ago, existing for approximately .-References:...

                        • Family Vombatidae: wombats
                        • Family Phalangeridae
                          Phalangeridae
                          Phalangeridae is a family of nocturnal marsupials native to Australia and New Guinea, including the cuscuses, brushtail possums, and their close relatives...

                          : phalangers
                        • Family Burramyidae: pygmy possums
                        • Family Macropodidae: rat kangaroos, kangaroos and wallabies
                        • Family Petauridae
                          Petauridae
                          The family Petauridae includes 11 medium-sized possum species: four striped possums, the six species wrist-winged gliders in genus Petaurus, and Leadbeater's Possum which has only vestigal gliding membranes...

                          : gliders
                        • Family †Ektopodontidae
                        • Family Phascolarctidae
                          Phascolarctidae
                          Phascolarctidae is a family of marsupials of the order Diprotodontia, consisting of only one extant species, the Koala, six well known fossil species, with another 5 less well known fossil species, and 2 fossil species whose taxonomy is debatable but is put in this group...

                          : koala
                        • Family †Pilkipildridae
                        • Family †Miralinidae
                        • Family Acrobatidae
                          Acrobatidae
                          Acrobatidae is a small family of gliding marsupials containing two genera, each with a single species, the Feathertail Glider from Australia and Feather-tailed Possum from New Guinea....

                          : feather-tail glider, pen-tailed phalanger
                • Magnorder Ameridelphia
                  Ameridelphia
                  Ameridelphia is traditionally a superorder that includes all marsupials living in the Americas except for the Monito del Monte...

                  • Order Didelphimorphia
                    Didelphimorphia
                    Opossums make up the largest order of marsupials in the Western Hemisphere, including 103 or more species in 19 genera. They are also commonly called possums, though that term technically refers to Australian fauna of the suborder Phalangeriformes. The Virginia opossum was the first animal to be...

                    : opossums
                    • Family Didelphidae: opossums
                    • Family †Sparassocynidae
                  • Order Paucituberculata
                    • Family †Sternbergiidae
                    • Family Caenolestidae: rat or shrew opossums
                    • Family †Paleothentidae
                    • Family †Abderitidae
                    • Family †Sillustaniidae
                    • Family †Polydolopidae
                    • Family †Prepidolopidae
                    • Family †Bonapartheriidae
                    • Family †Argyrolagidae
                    • Family †Patagoniidae
                    • Family †Groeberiidae
                    • Family †Glasbiidae
                    • Family †Caroloameghiniidae
                  • Order †Sparassodonta
                    Sparassodonta
                    Sparassodonta is an extinct order of carnivorous metatherian mammals native to South America. They were once considered to be true marsupials, but are now thought to be a sister taxon to them. A number of these mammalian predators closely resemble placental predators that evolved separately on...

                    • Family †Mayulestidae
                    • Family †Hondadelphidae
                    • Family †Borhyaenidae
                      Borhyaenidae
                      The borhyaenids, members of the Borhyaenidae family of metatherians , were a carnivorous group of otter/wolverine-shaped marsupials in the order Sparassodonta. They lived in the Miocene of South America . Like most metatherians, they had a pouch to carry their offspring around...

              • Cohort Placentalia: placentals
                • Order †Bibymalagasia
                • Magnorder Xenarthra
                  Xenarthra
                  The superorder Xenarthra is a group of placental mammals , existent today only in the Americas and represented by anteaters, tree sloths, and armadillos. The origins of the order can be traced back as far as the Paleogene in South America...

                  : edentates
                  • Order Cingulata: armadillos and relatives
                    • Family Dasypodidae: armadillos
                    • Family †Peltephilidae
                    • Family †Pampatheriidae
                      Pampatheriidae
                      Pampatheridae is an ancient family, now extinct, of large armadillo-like plantigrade armored xenarthrans. They are related to Glyptodontidae, an extinct family of much larger and more heavily armored xenarthrans, as well as to smaller extant armadillos...

                    • Family †Palaeopeltidae
                    • Family †Glyptodontidae
                      Glyptodontidae
                      Glyptodonts were large, more heavily armored relatives of extinct pampatheres and modern armadillos.They first evolved during the Miocene in South America, which remained their center of species diversity...

                      : glyptodonts
                  • Order Pilosa
                    Pilosa
                    The order Pilosa is a group of placental mammals, extant today only in the Americas. It includes the anteaters and sloths, including the recently extinct ground sloths....

                    : anteaters, sloths, and relatives
                    • Family †Entelopidae
                    • Family Myrmecophagidae
                      Myrmecophagidae
                      Myrmecophagidae is a family of anteaters, the name being derived from the Ancient Greek words for 'ant' and 'eat' . Myrmecophagids are native to Central and South America, from southern Mexico to northern Argentina. There are 2 genera and 3 species in the family, consisting of the Giant Anteater,...

                      : giant anteaters and relatives
                    • Family Cyclopedidae
                      Cyclopedidae
                      Cyclopedidae is a family of anteaters that includes the silky anteater and its extinct relatives....

                      : pygmy anteater
                    • Family †Rathymotheriidae
                    • Family †Scelidotheriidae
                      Scelidotheriidae
                      Scelidotheriidae is a family of extinct mammals within the order of Pilosa and suborder Folivora. This family of ground sloths is related to the other families of extinct ground sloths, being the Megatheriidae, the Mylodontidae, the Nothrotheriidae, and the Orophodontidae...

                    • Family †Mylodontidae
                      Mylodontidae
                      Mylodontidae is a family of extinct mammals within the order of Pilosa and suborder Folivora living from approximately 23 mya—11,000 years ago, existing for approximately . This family of ground sloths is related to the other families of extinct ground sloths, being the Megatheriidae, the...

                    • Family †Megatheriidae
                      Megatheriidae
                      Megatheriidae is a family of extinct ground sloths that lived from approximately 23 mya—11,000 years ago, existing for approximately .Megatheriids appeared later in the Oligocene, some 30 million years ago, also in South America. The group includes the heavily-built Megatherium and Eremotherium...

                      : ground sloths
                    • Family Megalonychidae
                      Megalonychidae
                      Megalonychidae is a group of sloths including the extinct Megalonyx and the living two toed sloths. Megalonychids first appeared in the early Oligocene, about 35 million years ago, in southern Argentina , and spread as far as the Antilles by the early Miocene...

                      : two-toed sloths
                    • Family Bradypodidae: three-toed sloths
                • Magnorder Epitheria
                  Epitheria
                  Epitherians comprise all the placental mammals except the Xenarthra. They are primarily characterized by having a stirrup-shaped stapes in the middle ear, which allows for passage of a blood vessel. This is in contrast to the column-shaped stapes found in marsupials, monotremes, and xenarthrans...

                  : epitheres
                  • Superorder †Leptictida
                    Leptictida
                    Leptictida is an extinct order of placental mammals. According to cladistic studies, they may be related to Euarchontoglires , although they are more often regarded as the first branch to split from basal eutherians.- Description :The leptictids are a characteristic example of the...

                    • Family †Gypsonictopidae
                    • Family †Kulbeckiidae
                    • Family †Didymoconidae
                    • Family †Leptictidae
                  • Superorder Preptotheria
                    • Grandorder Anagalida
                      • Family †Zambdalestidae
                      • Family †Anagalidae
                      • Family †Pseudictopidae
                      • Mirorder Macroscelidea: elephant shrews
                        • Family Macroscelididae: elephant shrews
                      • Mirorder Duplicidentata
                        • Order †Mimotonida
                          • Family †Mimotonidae
                        • Order Lagomorpha
                          Lagomorpha
                          The lagomorphs are the members of the taxonomic order Lagomorpha, of which there are two living families, the Leporidae , and the Ochotonidae...

                          • Family Ochotonidae: pikas
                          • Family Leporidae
                            Leporidae
                            Leporids are the approximately 50 species of rabbits and hares which form the family Leporidae. The leporids, together with the pikas, constitute the mammalian order Lagomorpha. Leporids differ from pikas in having short furry tails, and elongated ears and hind legs...

                            : rabbits
                      • Mirorder Simplicidentata
                        Simplicidentata
                        Simplicidentata is a group of mammals that includes the rodents and their closest extinct relatives. The term has historically been used as an alternative to Rodentia, contrasting the rodents with their close relatives the lagomorphs...

                        • Order †Mixodontia
                          • Family †Eurymylidae
                            Eurymylidae
                            Eurymylidae is a family of extinct simplicidentates. Most authorities consider them to be basal to all modern rodents and may have been the ancestral stock whence the most recent common ancestor of all modern rodents arose...

                        • Order Rodentia: rodents
                          • Family †Alagomyidae
                            Alagomyidae
                            Alagomyidae is a family of rodents known from the late Paleocene and early Eocene of Asia and North America . Alagomyids have been identified as the most basal rodents, lying outside the common ancestry of living forms...

                          • Family †Laredomyidae
                          • Family †Ischyromyidae
                          • Family †Allomyidae
                          • Family Aplodontiidae: mountain beaver
                          • Family †Mylagaulidae
                            Mylagaulidae
                            The Mylagaulidae or mylagaulids are a prehistoric family of sciuromorph rodents. They are known from the Neogene of North America and China...

                          • Family †Theridomyidae
                          • Family †Reithroparamyidae
                          • Family Sciuridae: squirrels
                          • Family †Eutypomyidae
                            Eutypomyidae
                            Eutypomyidae is a family of extinct rodents from North America and Eurasia thought to be related to modern beavers....

                          • Family Castoridae
                            Castoridae
                            The family Castoridae contains the two living species of beaver and their fossil relatives. This was once a highly diverse group of rodents, but is now restricted to a single genus, Castor.- Characteristics :...

                            : beavers
                          • Family †Rhizospalacidae
                          • Family †Protoptychidae
                          • Family †Armintomyidae
                          • Family Dipodidae
                            Dipodidae
                            The Dipodidae, or dipodids, are a family of rodents found across the northern hemisphere. This family includes over 50 species among the 16 genera....

                            : jumping mice, jerboas
                          • Family †Simimyidae
                            Simimyidae
                            Simimyidae is a family of extinct rodents from North America....

                          • Family Muridae
                            Muroidea
                            Muroidea is a large superfamily of rodents. It includes hamsters, gerbils, true mice and rats, and many other relatives. They occupy a vast variety of habitats on every continent except Antarctica. Some authorities have placed all members of this group into a single family, Muridae, due to...

                            : rats, mice, and relatives
                          • Family Myoxidae: dormice
                          • Family †Eomyidae
                            Eomyidae
                            Eomyidae is a family of extinct rodents from North America and Eurasia related to modern day pocket gophers and kangaroo rats. The family includes the earliest known gliding rodent, Eomys -References:...

                          • Family †Florentiamyidae
                          • Family Geomyidae: pocket gophers, pocket mice, and kangaroo rats
                          • Family Pedetidae
                            Pedetidae
                            Pedetidae is a family of mammals from the rodent order. The two living species, the springhares, are distributed throughout much of southern Africa and also around Kenya, Tanzania and Uganda. Fossils have been found as far north as Turkey. Together with the anomalures, Pedetidae forms the suborder...

                            : springhaas
                          • Family †Parapedetidae
                          • Family †Zegdoumyidae
                          • Family Anomaluridae: scaly-tailed squirrels
                          • Family †Ivanantoniidae
                          • Family †Sciuravidae
                          • Family †Chapattimyidae
                          • Family †Cylindrodontidae
                          • Family Ctenodactylidae: gundis
                          • Family †Tsaganomyidae
                            Tsaganomyidae
                            Tsaganomyidae is an extinct family of rodents from Asia. It contains three genera. Tsaganomyids are generally considered to be related to the Hystricognathi...

                          • Family Hystricidae: Old World porcupines
                          • Family Erethizontidae: New World porcupines
                          • Family †Myophiomyidae
                            Myophiomyidae
                            The Myophiomyids are an extinct family of Old World hystricognaths....

                          • Family †Diamantomyidae
                            Diamantomyidae
                            Diamantomyidae is a family of extinct hystricognath rodents from Africa and Asia....

                          • Family †Phiomyidae
                            Phiomyidae
                            The Phiomyidae are a family of prehistoric rodents from Africa and Eurasia. A 2011 study placed Gaudeamus in a new family, gaudeamuridae.Genera include:* Acritophiomys* Andrewsimys* Elwynomys* Gaudeamus* Phiomys...

                          • Family †Kenyamyidae
                            Kenyamyidae
                            The Kenyamyidae are an extinct family of rodents from Africa....

                          • Family Petromuridae: rock rats
                          • Family Thryonomyidae: cane rats
                          • Family Bathyergidae: mole-rats
                          • Family †Bathyergoididae
                          • Family Agoutidae: agoutis and pacas
                          • Family †Eocardiidae
                            Eocardiidae
                            The Eocardiidae are an extinct family of caviomorph rodents from South America. The family is probably ancestral to the living family Caviidae , which includes cavies, maras, and capybaras and their relatives...

                          • Family Dinomyidae
                            Dinomyidae
                            Dinomyidae was once a very speciose group of South American hystricognath rodent, but now contains only a single living species, the Pacarana. The Dinomyidae included among its ranks the largest rodents known to date, the bison-sized Josephoartigasia monesi and the smaller Josephoartigasia magna...

                            : pacarana
                          • Family Caviidae
                            Caviidae
                            The cavy family is a family of rodents native to South America, and including the domestic guinea pig, wild cavies, and the capybara, among other animals...

                            : cavies
                          • Family Hydrochoeridae: capybara
                          • Family Octodontidae
                            Octodontidae
                            The Octodontidae are a family of rodents, restricted to south-western South America. Thirteen species of octodontid are recognised, arranged in nine genera. The best known species is the Degu, Octodon degus....

                            : degus, tuco-tucos
                          • Family Echimyidae: spiny rats, nutria
                          • Family Capromyidae: hutias
                          • Family †Heptaxodontidae
                          • Family Chinchillidae
                            Chinchillidae
                            The family Chinchillidae contains the chinchillas, viscachas, and their fossil relatives. They are restricted to southern and western South America, often in association with the Andes. They are large rodents, weighing from to , with strong hind legs and large ears...

                            : chinchillas, viscachas
                          • Family †Neoepiblemidae
                            Neoepiblemidae
                            The Neoepiblemidae are an extinct family of hystricognath rodents from South America. The genus Dabbenea, formerly placed here, is now included in Phoberomys...

                          • Family Abrocomidae: rat chinchillas
                    • Grandorder Ferae
                      Ferae
                      Ferae is a clade of mammals, consisting of the orders Carnivora and Pholidota . Pangolins do not look much like carnivorans , and were thought to be the closest relatives of Xenarthra...

                      • Order Cimolesta
                        Cimolesta
                        Cimolesta is an extinct order of mammals. A few experts place the pangolins within Cimolesta, though most other experts prefer to place the pangolins within their own order, Pholidota....

                         - pangolins and relatives
                        • Family †Palaeoryctidae
                          Palaeoryctidae
                          Palaeoryctidae is an extinct group of relatively non-specialized placental mammals that strived in North America during the late Cretaceous and took part in the first placental evolutionary radiation together with other early mammals such as the leptictids.- Description :From a near-complete skull...

                        • Family †Cimolestidae
                        • Family †Apatemyidae
                          Apatemyidae
                          Apatemyidae is an extinct family of placental mammals that took part in the first placental evolutionary radiation together with other early mammals such as the leptictids....

                        • Family †Stylinodontidae
                          Taeniodont
                          The taeniodonts were an early group of mammals who lived from the Palaeocene to the Eocene. This group evolved quickly into highly specialized digging animals. Taeniodont species varied greatly in size, from rat-sized to species as large as a bear. Later species developed prominent front teeth and...

                        • Family †Tillotheriidae
                        • Family †Wangliidae
                        • Family †Harpyodidae
                        • Family †Bemalambdidae
                        • Family †Pastoralodontidae
                        • Family †Titanoideidae
                        • Family †Pantolambdidae
                        • Family †Barylambdidae
                        • Family †Cyriacotheriidae
                        • Family †Pantolambdodontidae
                        • Family †Coryphodontidae
                        • Family †Pantolestidae
                          Pantolestidae
                          Pantolestidae is an extinct family of semi-aquatic, placental mammals that took part in the first placental evolutionary radiation together with other early mammals such as the leptictids....

                        • Family †Paroxyclaenidae
                        • Family †Ptolemaiidae
                        • Family †Epoicotheriidae
                          Epoicotheriidae
                          Epoicotheriidae is an extinct family of pangolin-like insectivore mammals which were endemic to North America from the Eocene to the Oligocene 55.4—33.9 Ma existing for approximately ..Epoicotheriids were highly specialized animals that were convergent on golden moles in the structure of their...

                        • Family †Metacheiromyidae
                        • Family Manidae: pangolins
                        • Family †Ernanodontidae
                      • Order †Creodonta
                        Creodonta
                        The creodonts are an extinct order of mammals that lived from the Paleocene to the Miocene epochs. They shared a common ancestor with the Carnivora....

                        : creodonts
                        • Family †Hyaenodontidae
                          Hyaenodontidae
                          Hyaenodontidae is a family of the extinct order Creodonta, which contains several dozen genera.The Hyaenodontids were important mammalian predators that arose during the late Paleocene and persisted well into the Miocene...

                        • Family †Oxyaenidae
                          Oxyaenidae
                          Oxyaenidae is a family of the extinct order Creodonta; it contains three subfamilies comprising ten genera. The placement of a fourth subfamily, Machaeroidinae, is unsure; it may belong here or in Hyaenodontidae....

                      • Order Carnivora
                        Carnivora
                        The diverse order Carnivora |Latin]] carō "flesh", + vorāre "to devour") includes over 260 species of placental mammals. Its members are formally referred to as carnivorans, while the word "carnivore" can refer to any meat-eating animal...

                        • Family †Viverravidae
                        • Family †Nimravidae
                          Nimravidae
                          The Nimravidae, sometimes known as false saber-toothed cats, are an extinct family of mammalian carnivores belonging to the suborder Feliformia and endemic to North America, Europe, and Asia living from the Eocene through the Miocene epochs , existing for approximately .-Morphology:Although some...

                        • Family Felidae
                          Felidae
                          Felidae is the biological family of the cats; a member of this family is called a felid. Felids are the strictest carnivores of the thirteen terrestrial families in the order Carnivora, although the three families of marine mammals comprising the superfamily pinnipedia are as carnivorous as the...

                          : cats
                        • Family Viverridae: civets, Asiatic palm civets
                        • Family Herpestidae: mongooses
                        • Family Hyaenidae: hyaenas, aardwolf
                        • Family Nandiniidae: African palm civets
                        • Family †Miacidae
                        • Family Canidae
                          Canidae
                          Canidae is the biological family of carnivorous and omnivorous mammals that includes wolves, foxes, jackals, coyotes, and domestic dogs. A member of this family is called a canid . The Canidae family is divided into two tribes: Canini and Vulpini...

                          : dogs
                        • Family †Amphicyonidae
                        • Family Ursidae: bears
                        • Family †Hemicyonidae
                          Hemicyonidae
                          Hemicyonidae is an extinct family of so-called "dog-bears", literally "Half Dog" , bear-like carnivoran living in Europe, North America, Africa, and Asia during the Oligocene through Miocene epochs 33.9—5.3 Ma, existing for approximately ....

                        • Family Otariidae: eared seals
                        • Family Phocidae: seals, walrus
                        • Family Mustelidae
                          Mustelidae
                          Mustelidae , commonly referred to as the weasel family, are a family of carnivorous mammals. Mustelids are diverse and the largest family in the order Carnivora, at least partly because in the past it has been a catch-all category for many early or poorly differentiated taxa...

                          : weasels, skunks, and relatives
                        • Family Procyonidae
                          Procyonidae
                          Procyonidae is a New World family of the order Carnivora. It includes the raccoons, coatis, kinkajous, olingos, ringtails and cacomistles. Procyonids inhabit a wide range of environments, and are generally omnivorous.-Characteristics:...

                          : ringtails, olingos, kinkajou, raccoons, coatis, red panda
                    • Grandorder Lipotyphla
                      • Family †Adapisoriculidae
                        • Order Chrysochloridea
                          • Family Chrysochloridae: golden moles
                        • Order Erinaceomorpha
                          • Family †Sespedectidae
                          • Family †Amphilemuridae
                          • Family †Adapisoricidae
                            Adapisoricidae
                            Adapisoriculidae is an extinct family of placental mammals present during the Paleocene and possibly Cretaceous. They were once thought to be members of the order Erinaceomorpha,...

                          • Family †Creotarsidae
                          • Family Erinaceidae
                            Erinaceidae
                            Erinaceidae is the only living family in the order Erinaceomorpha, which has recently been subsumed with Soricomorpha into the order Eulipotyphla...

                            : hedgehogs and relatives
                          • Family †Proscalopidae
                          • Family Talpidae
                            Talpidae
                            The family Talpidae includes the moles, shrew moles, desmans, and other intermediate forms of small insectivorous mammals of the order Soricomorpha...

                            : moles
                          • Family †Dimylidae
                        • Order Soricomorpha
                          Soricomorpha
                          The order Soricomorpha is taxon within the class of mammals. In previous years it formed a significant group within the former order Insectivora...

                          • Family †Otlestidae
                          • Family †Geolabididae
                          • Family †Nesophontidae: recently extinct west Indian shrews
                          • Family †Micropternodontidae
                          • Family †Apternodontidae
                          • Family Solenodontidae
                            Solenodontidae
                            Solenodons are venomous, nocturnal, burrowing, insectivorous mammals belonging to the family Solenodontidae. Only one genus, Solenodon, is known, although a few other genera were erected at one time and are now regarded as junior synonyms...

                            : solenodons
                          • Family †Plesiosoricidae
                          • Family †Nyctitheriidae
                          • Family Soricidae: shrews
                          • Family Tenrecidae
                            Tenrecidae
                            Tenrecidae is a family of mammals found on Madagascar and parts of Africa. Tenrecs are widely diverse, resembling hedgehogs, shrews, opossums, mice and even otters, as a result of convergent evolution. They occupy aquatic, arboreal, terrestrial and fossorial environments...

                            : tenrecs
                    • Grandorder Archonta
                      Archonta
                      The Archonta are a group of mammals considered a superorder in some classifications.The Archonta consist of the following orders:*Primates*Plesiadapiformes *Scandentia *Dermoptera *Chiroptera...

                      • Order Chiroptera: bats
                        • Family Pteropodidae: flying foxes
                        • Family †Archaeonycteridae
                          Archaeonycteridae
                          Archaeonycteridae is a family of extinct bats. It was originally erected by the Swiss naturalist Pierre Revilliod as Archaeonycterididae to hold the genus Archaeonycteris. It was formerly classified under the superfamily Icaronycteroidea by Kurten and Anderson in 1980...

                        • Family †Paleochiropterygidae
                        • Family †Hassianycterididae
                        • Family Emballonuridae: sac-winged bats
                        • Family Rhinopomatidae
                          Rhinopomatidae
                          Mouse-tailed bats are a group of insectivorous bats of the family Rhinopomatidae with only three to five species, all contained in the single genus Rhinopoma. They are found in the Old World, from North Africa to Thailand and Sumatra, in arid and semi-arid regions, roosting in caves, houses and...

                          : mouse-tailed bats
                        • Family Craseonycteridae: bumblebee bats
                        • Family Megadermatidae
                          Megadermatidae
                          Megadermatidae, or False Vampire Bats, are a family of bats found from central Africa, eastwards through southern Asia, and into Australia. They are relatively large bats, ranging from 6.5 cm to 14 cm in head-body length. They have large eyes, very large ears and a prominent nose-leaf. They have a...

                          : false vampire bats
                        • Family Nycteridae
                          Nycteridae
                          Nycteridae is the family of slit-faced or hollow-faced bats. They are grouped in a single genus, Nycteris. The bats are found in East Malaysia, Indonesia and many parts of Africa....

                          : hispid bats
                        • Family Rhinolophidae: horseshoe and Old World leaf-nosed bats
                        • Family Mystacinidae
                          Mystacinidae
                          Mystacinidae is a family of unusual bats, the New Zealand short-tailed bats. There is one living genus, Mystacina, with two extant species, one of which is believed to have become extinct in the 1960s. They are medium-sized bats, about in length, with grey, velvety fur.Mystacinids are the most...

                          : New Zealand short-tailed bats
                        • Family Noctilionidae: fishing bats
                        • Family Mormoopidae
                          Mormoopidae
                          The family Mormoopidae contains bats known generally as mustached bats, ghost-faced bats, and naked-backed bats. They are found in the Americas from the Southwestern United States to Southeastern Brazil....

                          : spectacled bats
                        • Family Phyllostomidae: New World leaf-nosed and vampire bats
                        • Family †Philisidae
                        • Family Molossidae: free-tailed bats
                        • Family Natalidae
                          Natalidae
                          The family Natalidae, or funnel-eared bats are found from Mexico to Brazil and the Caribbean islands. The family has three genera, Chilonatalus, Natalus and Nyctiellus. They are slender bats with unusually long tails and, as their name suggests, funnel-shaped ears. They are small, at only 3.5 to...

                          : funnel-eared bats
                        • Family Furipteridae
                          Furipteridae
                          Furipteridae is one of the families of bats. This family contains only two species, the Smokey Bat and the Thumbless Bat. Both are from Central and South America, and are closely related to the bats in the Natalidae and Thyropteridae families. They can be recognized by their reduced and...

                          : smoky bats
                        • Family Thyropteridae
                          Thyropteridae
                          Disc-winged bats are a small group of bats of the family Thyropteridae. They are found in Central and South America, usually in moist tropical rain forests. It is a very small family, consisting of a single genus with four species....

                          : New World sucker-footed bats
                        • Family Myzopodidae: Old World sucker-footed bats
                        • Family Vespertilionidae: common bats
                      • Order Primates: primates
                        • Family †Purgatoriidae
                        • Family †Microsyopidae
                        • Family †Micromomyidae
                        • Family †Picromomyidae
                        • Family †Plesiadapidae
                          Plesiadapidae
                          Plesiadapidae is a family of plesiadapiform mammals related to primates known from the Paleocene and Eocene of North America, Europe, and Asia...

                        • Family †Palaechthonidae
                        • Family †Picrodontidae
                        • Family †Paramomyidae
                        • Family †Plagiomenidae
                        • Family †Mixodectidae
                          Mixodectidae
                          Mixodectidae or mixodectids is an extinct family of insectivore, placental mammals in the order Dermoptera....

                        • Family Galeopithecidae: colugos
                        • Family †Plesiopithecidae
                        • Family Daubentoniidae: aye-aye
                        • Family †Adapidae
                        • Family Lemuridae
                          Lemuridae
                          Lemuridae is a family of prosimian primates native to Madagascar, and one of five families commonly known as lemurs. These animals were thought to be the evolutionary predecessors of monkeys and apes, but this is no longer considered correct...

                          : lemurs
                        • Family Lorisidae
                          Lorisidae
                          Lorisidae is a family of strepsirrhine primates. The lorisids are all slim arboreal animals and include the lorises, pottos and angwantibos. Lorisids live in tropical, central Africa as well as in south and southeast Asia....

                          : lorises and galagos
                        • Family Cheirogaleidae
                          Cheirogaleidae
                          Cheirogaleidae is the family of strepsirrhine primates that contains the various dwarf and mouse lemurs. Like all other lemurs, cheirogaleids live exclusively on the island of Madagascar.-Characteristics:...

                          : dwarf lemurs
                        • Family †Archaeolemuridae
                        • Family †Palaeopropithecidae
                        • Family Indriidae
                          Indriidae
                          The Indriidae are a family of strepsirrhine primates. They are medium to large sized lemurs with only four teeth in the toothcomb instead of the usual six...

                          : indris and sifakas
                        • Family †Carpolestidae
                          Carpolestidae
                          Carpolestidae is a family of primate-like Plesiadapiformes that were prevalent in North America and Asia from the mid Paleocene through the early Eocene. Typically, they are characterized by two large upper posterior premolars and one large lower posterior premolar. They weighed about 20-150g, and...

                        • Family †Omomyidae
                        • Family †Microchoeridae
                        • Family †Afrotarsiidae
                        • Family Tarsiidae: tarsiers
                        • Family †Eosimiidae
                          Eosimiidae
                          Eosimiidae is the family of extinct primates believed to be the earliest simians....

                        • Family †Parapithecidae
                          Parapithecidae
                          Parapithecidae is an extinct family of primates which lived in the Eocene and Oligocene periods in Egypt. Eocene fossils from Burma are sometimes included in the family in addition. They showed certain similarities in dentition to Condylarthra, but had short faces and jaws shaped like those of...

                        • Family †Pliopithecidae
                          Pliopithecidae
                          The family Pliopithecidae is the earliest known family of fossil apes. They originated in Africa, and subsequently spread to Europe, before becoming extinct about 10 million years ago. Like modern gibbons, they were adapted to living in the tree tops of dense forests. Their anatomy combined...

                        • Family Cercopithecidae: Old World monkeys including colobuses
                        • Family Hominidae
                          Hominidae
                          The Hominidae or include them .), as the term is used here, form a taxonomic family, including four extant genera: chimpanzees , gorillas , humans , and orangutans ....

                          : humans, greater apes, lesser apes
                        • Family Callitrichidae: marmosets
                        • Family Atelidae
                          Atelidae
                          Atelidae is one of the five families of New World monkeys now recognised. It was formerly included in the family Cebidae. Atelids are generally larger monkeys; the family includes the howler, spider, woolly and woolly spider monkeys...

                          : New World monkeys
                      • Order Scandentia
                        • Family Tupaiidae
                          Tupaiidae
                          Tupaiidae is one of two families of treeshrews, the other family being Ptilocercidae. It contains 4 genera and 19 species.-Taxonomy:*Order: Scandentia** Family Tupaiidae*** Genus Anathana**** Madras Treeshrew, Anathana ellioti...

                          : tree shrews
                    • Grandorder Ungulata: ungulates
                      • Order Tubulidentata
                        • Family Orycteropodidae
                          Orycteropodidae
                          Orycteropodidae is a family of afrotherian mammals. Although there are many fossil species, the only species surviving today is the aardvark, Orycteropus afer. Orycteropodidae is recognized as the only family within the order Tubulidentata, so the two are effectively synonyms.The family arose in...

                          : aardvark
                      • Order †Dinocerata
                        Dinocerata
                        Dinocerata mammals are an extinct order of plant-eating, rhinoceros-like hoofed creatures famous for their paired horns and tusk-like canine teeth...

                        • Family †Uintatheriidae
                          Uintatheriidae
                          The Uintatheriidae is a family of extinct mammals that includes Uintatherium. They belong to the order Dinocerata, one of several extinct orders of primitive mammals that are sometimes united in the Condylarthra....

                      • Mirorder Eparctocyona
                        • Order †Procreodi
                          • Family †Oxyclaenidae
                          • Family †Arctocyonidae
                            Arctocyonidae
                            Arctocyonidae is an extinct family of unspecialized, primitive mammals with more than 20 genera most abundant during the Paleocene, but extant from the late Cretaceous to the early Eocene ....

                        • Order †Condylarthra
                          • Family †Hyopsodontidae
                            Hyopsodontidae
                            Hyopsodontidae is an extinct family of unspecialized, primitive mammals from the Condylarthra order, living from the Paleocene to the Eocene in North America and EurasiaThey were generally small insectivorous animals. The most common genus is Hyopsodus....

                          • Family †Mioclaenidae
                          • Family †Phenacodontidae
                            Phenacodontidae
                            An extinct family of large herbivorous mammals in the order Condylarthra.Dentition shows that species like Pleuraspidotherium and its relatives were probably browsers....

                          • Family †Periptychidae
                            Periptychidae
                            Periptychidae is a family of Paleocene placental mammals, known definitively only from North America. The family is part of a radiation of early herbivorous and omnivorous mammals classified in the extinct order Condylarthra, which may be related to some or all living ungulates...

                          • Family †Peligrotheriidae
                          • Family †Didolodontidae
                        • Order †Arctostylopida
                          Arctostylopida
                          Arctostylopida is an extinct order of placental mammals. They're animals of uncertain affinities to other groups and it was believed that they may be related to ungulates. Originally they were considered to be Northern relatives of Southern American notoungulates, closer to Notostylopidae...

                          • Family †Arctostylopidae
                        • Order Cete
                          Cete
                          Cete is a Portuguese parish of the municipality of Paredes. It is 4.35 km² in area, with 2,517 inhabitants as of 2001....

                          : whales and relatives
                          • Family †Triisodontidae
                            Triisodontidae
                            Triisodontidae is an extinct family of mesonychian placental mammals. Most triisodontid genera lived during the early Paleocene in North America, but the genus Andrewsarchus is known from the late Eocene of Asia. Triisodontids were the first relatively large predatory mammals to appear in North...

                          • Family †Mesonychidae
                            Mesonychidae
                            Mesonychidae is an extinct family of medium to large-sized omnivorous-carnivorous mammals closely related to artiodactyls which were endemic to North America and Eurasia during the Early Paleocene to Late Eocene living from 65—33.9 mya, existing for approximately .- Description :The mesonychids...

                            : mesonychids
                          • Family †Hapalodectidae
                            Hapalodectidae
                            Hapalodectidae is an extinct family of relatively small-bodied mesonychian placental mammals from the Paleocene and Eocene of North America and Asia...

                          • Family †Basilosauridae
                            Basilosauridae
                            Basilosauridae is family of extinct cetaceans that lived in tropical seas during the late Eocene.-Taxonomy:*Family Basilosauridae** Subfamily Basilosaurinae*** Genus Basilosaurus*** Genus Basiloterus** Subfamily Dorudontinae...

                          • Family †Protocetidae
                            Protocetidae
                            The protocetids form a diverse and heterogeneous group of cetaceans known from Asia, Europe, Africa, and North America. There were many genera, and some of these are very well known . Known protocetids had large fore- and hindlimbs that could support the body on land, and it is likely that they...

                          • Family †Remingtonocetidae
                            Remingtonocetidae
                            Remingtonocetidae is a family of early carnivorous freshwater aquatic mammals of the order Cetacea endemic to the coastline of the ancient Tethys Ocean during the Eocene living from 55.8—48.6 mya, existing for approximately ....

                          • Family †Agorophiidae
                          • Family †Squalodontidae
                          • Family †Rhabdosteidae
                          • Family †Aetiocetidae
                          • Family †Mammalodontidae
                            Mammalodontidae
                            Mammalodontidae is an extinct family of whales known from the Oligocene of Australia.There are currently two genera is this family: Janjucetus and Mammalodon. After a new cladistic analysis by Fitzgerald , Janjucetus was transferred into Mammalodontidae, thereby making Janjucetidae a junior synonym...

                          • Family †Cetotheriidae
                            Cetotheriidae
                            Cetotheriidae is an extinct family of baleen whales in the suborder Mysticeti. The family existed from the Late Oligocene to the Late Pliocene before going extinct.-Taxonomy:...

                          • Family Balaenopteridae: rorquals and grey whales
                          • Family Balaenidae
                            Balaenidae
                            Balaenidae is a family of mysticete whales that contains two living genera. Commonly called the right whales as it contains mainly right whale species...

                            : right and bowhead whales
                          • Family Physeteridae: sperm whales
                          • Family Hyperoodontidae: beaked whales
                          • Family Platanistidae: river dolphins
                          • Family Delphinidae: dolphins
                          • Family Pontoporiidae: La Plata River dolphin
                          • Family Lipotidae: baiiji
                          • Family Iniidae
                            Iniidae
                            Iniidae is a family of river dolphins containing one living and three extinct genera.-Taxonomy:The family was described by John Edward Gray in 1846.Current classifications include a single living genera, Inia, with one species and three subspecies...

                            : Amazon River dolphin
                          • Family †Kentridontidae
                          • Family Monodontidae
                            Monodontidae
                            The cetacean family Monodontidae comprises two unusual whale species, the narwhal, in which the male has a long tusk, and the white beluga whale...

                            : beluga and narwhal
                          • Family †Odobenocetopsidae
                          • Family †Dalpiazinidae
                          • Family †Acrodelphinidae
                          • Family Phocoenidae: porpoises
                          • Family †Albireonidae
                          • Family †Hemisyntrachelidae
                        • Order Artiodactyla: even-toed ungulates
                          • Family †Raoellidae
                            Raoellidae
                            Previously grouped with Helohyidae, Raoellidae is now a family in the Suborder Cetancodonta. It is found in Eocene of South and Southeast Asia....

                          • Family †Choeropotamidae
                          • Family Suidae
                            Suidae
                            Suidae is the biological family to which pigs belong. In addition to numerous fossil species, up to sixteen extant species are currently recognized, classified into between four and eight genera...

                            : pigs
                          • Family Tayassuidae: peccaries
                          • Family †Santheriidae
                          • Family Hippopotamidae
                            Hippopotamidae
                            Hippopotamuses are the members of the family Hippopotamidae. They are the only extant artiodactyls which walk on four toes on each foot.- Characteristics :...

                            : hippos
                          • Family †Dichobunidae
                            Dichobunidae
                            Dichobunidae is an extinct family of early even-toed hoofed mammals known from the early Eocene to late Oligocene of North America, Europe, and Asia. Dichobunidae includes some of the earliest known artiodactyls, such as Diacodexis....

                          • Family †Cebochoeridae
                          • Family †Mixtotheriidae
                          • Family †Helohyidae
                          • Family †Haplobunodontidae
                          • Family †Anthracotheriidae
                            Anthracotheriidae
                            Anthracotheriidae is a family of extinct, hippopotamus-like artiodactyl ungulates related to hippopotamuses and whales. The oldest genus, Elomeryx, first appeared during the Middle Eocene in Asia...

                          • Family †Dacrytheriidae
                          • Family †Anoplotheriidae
                            Anoplotheriidae
                            Anoplotheriidae is an extinct family of even-toed ungulates , endemic to Europe during the Eocene and Oligocene 48.6—23.030 Ma, existing for approximately . They were, most likely, all terrestrial herbivores.-Taxonomy:...

                          • Family †Cainotheriidae
                          • Family †Agriochoeridae
                          • Family †Oreodont
                            Oreodont
                            Oreodons, sometimes called prehistoric "ruminating hogs," were a family of cud-chewing plant-eater with a short face and tusk-like canine teeth...

                            idae
                          • Family †Entelodontidae
                          • Family †Xiphodontidae
                            Xiphodontidae
                            Xiphodontidae is an extinct family of even-toed ungulates , endemic to Europe during the Eocene 40.4—33.9 Ma, existing for approximately .. They were, most likely, all terrestrial herbivores.-Taxonomy:...

                          • Family Camelidae: camels and llamas
                          • Family †Oromerycidae
                            Oromerycidae
                            Oromerycidae is a small extinct family of artiodactyls closely related to living camels, known from the middle to late Eocene of western North America....

                          • Family †Protoceratidae
                            Protoceratidae
                            Protoceratidae is an extinct family of herbivorous North American artiodactyls that lived during the Eocene through Pliocene at around 46.2—4.9 Ma., existing for approximately .-Taxonomy:...

                          • Family †Amphimerycidae
                          • Family †Hypertragulidae
                            Hypertragulidae
                            Hypertragulidae is an extinct family of even-toed ungulates , endemic to North America, Europe, and Asia during the Eocene through Miocene, living 46.2—13.6 Ma, existing for approximately ....

                          • Family Tragulidae: mouse deer
                          • Family †Leptomerycidae
                          • Family †Bachitheriidae
                          • Family †Lophiomerycidae
                          • Family †Gelocidae
                          • Family Moschidae: musk deer
                          • Family Antilocapridae: pronghorn
                          • Family †Palaeomerycidae
                            Palaeomerycidae
                            Palaeomerycidae is an extinct family of ruminants , probably ancestral to deer and musk deer...

                          • Family †Hoplitomerycidae
                          • Family Cervidae: deer
                          • Family †Climacoceratidae
                            Climacoceratidae
                            Climacoceratidae is a family of superficially deer-like artiodactyl ungulates that were restricted to the Miocene of Africa. They are close to the ancestry of giraffes, with some genera, such as Prolibytherium, having originally identified as being giraffes.The climacoceratids, namely, of what is...

                          • Family Giraffidae
                            Giraffidae
                            The giraffids are ruminant artiodactyl mammals that share a common ancestor with deer and bovids. The biological family Giraffidae, once a diverse group spread throughout Eurasia and Africa, contains only two living members, the giraffe and the okapi. Both are confined to sub-saharan Africa: the...

                            : giraffe and okapi
                          • Family Bovidae: cattle, antelope, and relatives
                      • Mirorder †Meridiungulata
                        Meridiungulata
                        Meridiungulata is an extinct clade with the rank of cohort or super-order, containing the South-American ungulates: Pyrotheria , Astrapotheria, Notoungulata and Litopterna...

                        • Family †Perutheriidae
                        • Family †Amilnedwardsiidae
                        • Order †Litopterna
                          Litopterna
                          Litopterna is an extinct order of fossil hoofed mammals from the Tertiary period that displays toe reduction. Three-toed, and even a one-toed horselike form developed....

                          • Family †Protolipternidae
                          • Family †Macraucheniidae
                            Macraucheniidae
                            Macraucheniidae is a family in the Litopterna order of extinct South American ungulates. The recessed nasal bones of their skulls suggest that they may have had a small proboscis, or trunk. Their hooves were similar to those of rhinoceroses today, with a simple ankle joint and three digits on each...

                          • Family †Notonychopidae
                          • Family †Adianthidae
                          • Family †Proterotheriidae
                            Proterotheriidae
                            Proterotheriidae is an extinct family of fossil ungulates from the Tertiary period that displays toe reduction. Despite resembling primitive, small horses, they were not related to them, but belonged to the order Litopterna....

                        • Order †Notoungulata
                          Notoungulata
                          Notoungulata is an extinct order of hoofed, sometimes heavy bodied mammalian ungulates which inhabited South America during the Paleocene to Pleistocene, living from approximately 57 Ma to 11,000 years ago.-Taxonomy:...

                          : notoungulates
                          • Family †Henricosborniidae
                            Henricosborniidae
                            Henricosborniidae is an extinct family comprising four genera of notoungulate mammals known from the Paleocene and early Eocene of South America....

                          • Family †Notostylopidae
                            Notostylopidae
                            Notostylopidae is an extinct family comprising five genera of notoungulate mammals known from the early Eocene to early Oligocene of South America...

                          • Family †Isotemnidae
                            Isotemnidae
                            Isotemnidae is an extinct family of notoungulate mammals known from the Paleocene through Oligocene of South America....

                          • Family †Leontiniidae
                            Leontiniidae
                            Leontiniidae is an extinct family comprising six genera of notoungulate mammals known from the middle Eocene through middle Miocene of South America .-References:...

                          • Family †Notohippidae
                            Notohippidae
                            Notohippidae is an extinct family of notoungulate mammals from South America. Notohippids are known from the Eocene and Oligocene epochs....

                          • Family †Toxodontidae
                            Toxodontidae
                            Toxodontidae is an extinct family of notoungulate mammals known from the Oligocene through the Pleistocene of South America, with one genus, Mixotoxodon, also known from the Pleistocene of Central America. They somewhat resembled rhinoceroses, and had teeth with high crowns and open roots,...

                          • Family †Homalodotheriidae
                            Homalodotheriidae
                            Homalodotheriidae is an extinct family comprising four genera of notoungulate mammals known from the late Eocene through late Miocene of South America....

                          • Family †Archaeopithecidae
                            Archaeopithecidae
                            Archaeopithecidae is an extinct family comprising two genera of notoungulate mammals, Acropithecus and Archaeopithecus, both known from the early Eocene of South America .-References:...

                          • Family †Oldfieldthomasiidae
                            Oldfieldthomasiidae
                            Oldfieldthomasiidae is an extinct family of notoungulate mammals known from the Paleocene and Eocene of South America....

                          • Family †Interatheriidae
                            Interatheriidae
                            Interatheriidae is an extinct family of notoungulate mammals from South America. Interatheriids are known from the Paleocene or Eocene through the Miocene .-References:...

                          • Family †Campanorcidae
                          • Family †Mesotheriidae
                            Mesotheriidae
                            Mesotheriidae is an extinct family of notoungulate mammals known from the Eocene through the Pleistocene of South America. Mesotheriids were small to medium-sized herbivorous mammals adapted for digging.-Characteristics:...

                          • Family †Archaeohyracidae
                            Archaeohyracidae
                            Archaeohyracidae is an extinct family comprising four genera of notoungulate mammals known from the Paleocene through the Oligocene of South America....

                          • Family †Hegetotheriidae
                            Hegetotheriidae
                            Hegetotheriidae is an extinct family of notoungulate mammals known from the Eocene through the Pleistocene of South America...

                        • Order †Astrapotheria
                          Astrapotheria
                          Astrapotheria is an extinct order of South American hoofed animals. The history of this order is enigmatic, but it may taxonomically belong to Meridiungulata . In turn, Meridungulata is believed to belong to the extant superorder Laurasiatheria...

                          • Family †Eoastrapostylopidae
                          • Family †Trigonostylopidae
                          • Family †Astrapotheriidae
                        • Order †Xenungulata
                          • Family †Carodniidae
                        • Order †Pyrotheria
                          Pyrotheria
                          Pyrotheria is an order of extinct meridiungulate mammals. These mastodon-like ungulates include the genera Baguatherium, Carolozittelia, Colombitherium, Gryphodon, Propyrotherium, Proticia, and Pyrotherium....

                          • Family †Pyrotheriidae
                            Pyrotheriidae
                            Pyrotheriidae is the only family in the order Pyrotheria, provided one does not include the Paleocene genus, Carodnia. These extinct, mastodon-like ungulates include the genera Baguatherium, Carolozittelia, Colombitherium, Gryphodon, Propyrotherium, Proticia, and Pyrotherium.-References:**...

                      • Mirorder Altungulata
                        • Order Perissodactyla: odd-toed ungulates
                          • Family Equidae
                            Equidae
                            Equidae is the taxonomic family of horses and related animals, including the extant horses, donkeys, and zebras, and many other species known only from fossils. All extant species are in the genus Equus...

                            : horses
                          • Family †Palaeotheriidae
                            Palaeotheriidae
                            Palaeotheres are an extinct group of herbivorous mammals related to tapirs and rhinoceros, and probably ancestral to horses. They ranged across Europe and Asia during the Eocene through Oligocene 55—28 Ma, existing for approximately ....

                          • Family †Brontotheriidae
                            Brontotheriidae
                            Brontotheriidae, also called Titanotheriidae, is a family of extinct mammals belonging to the order Perissodactyla, the order that includes horses, rhinoceroses, and tapirs. Superficially they looked rather like rhinos, although they were not true rhinos and are probably most closely related to...

                          • Family †Anchilophidae
                          • Family †Eomoropidae
                            Eomoropidae
                            Eomoropidae is a family of odd-toed ungulates, a group which also includes horses, rhinoceroses, and tapirs. They were most closely related to the extinct chalicotheres, which they greatly resemble, and may have been their immediate ancestors. They were, however, much smaller than the later forms,...

                          • Family †Chalicotheriidae
                          • Family †Hyracodontidae
                            Hyracodontidae
                            Hyracodontidae is an extinct family of rhinoceroses endemic to North America, Europe, and Asia during the Eocene through early Miocene living from 55.8—20 mya, existing for approximately .They are typified as having long limbs and having no horns...

                          • Family Rhinocerotidae: rhinoceroses
                          • Family †Helaletidae
                          • Family †Isectolophidae
                          • Family †Lophiodontidae
                          • Family †Deperetellidae
                          • Family †Lophialetidae
                          • Family Tapiridae: tapirs
                        • Order Uranotheria: elephants, manatees, hyraxes, and relatives
                          • Family †Pliohyracidae
                          • Family Procaviidae: hyraxes
                          • Family †Phenacolophidae
                          • Family †Arsinoitheriidae
                            Arsinoitheriidae
                            Arsinoitheriidae was a family of mammals belonging to the extinct order Embrithopoda. Remains have been found in the Middle East, Africa, Asia and Romania. When alive, they would have had a great, albeit very superficial, resemblance to the modern rhinoceros...

                          • Family †Prorastomidae
                            Prorastomidae
                            Prorastomidae is a taxonomic family of extinct animals related to the extant manatees and dugong. The family includes two genera:*Pezosiren*Prorastomus...

                          • Family Dugongidae
                            Dugongidae
                            Dugongidae is a family in the order of Sirenia.The family has one surviving species, the Dugong , one recently extinct species, the Steller's Sea Cow , and a number of extinct genera known from the fossil record....

                            : dugongs
                          • Family Trichechidae: manatees
                          • Family †Desmostylidae
                            Desmostylidae
                            Desmostylidae is an extinct family of herbivorous marine mammal belonging to the order of Desmostylia living along the coast of the Pacific Ocean from the Rupelian stage of the Early Oligocene through the Chattian stage of the Late Oligocene existing for approximately .Desmostylidae are...

                          • Family †Anthracobunidae
                            Anthracobunidae
                            Anthracobunidae is an extinct family of primitive proboscideans that lived in the early to middle Eocene period.They resemble the later Moeritheriidae in both size and cheek tooth morphology but lack their characteristic tusks. They are known only from fragmentary remains from Eocene deposits of...

                          • Family †Moeritheriidae
                          • Family †Numidotheriidae
                            Numidotheriidae
                            Numidotheriidae is an extinct family of primitive proboscidean that lived from the late Paleocene to the early Eocene periods of North Africa....

                          • Family †Barytheriidae
                          • Family †Deinotheriidae
                            Deinotheriidae
                            Deinotheriidae is a family of prehistoric elephant-like proboscideans that lived during the Tertiary period, first appearing in Africa, then spreading across southern Asia and Europe. During that time they changed very little, apart from growing much larger in size - by the late Miocene they had...

                          • Family †Palaeomastodontidae
                          • Family †Phiomiidae
                          • Family †Hemimastodontidae
                          • Family †Mammutidae
                            Mammutidae
                            Mammutidae is a family of extinct proboscideans that lived between the Miocene to the Pleistocene or Holocene. The family was first described in 1922, classifying fossil specimens of the type genus Mammut , and has since been placed in various arrangements of the order...

                            : mastodons and relatives
                          • Family †Gomphotheriidae: gomphotheres
                          • Family Elephantidae
                            Elephantidae
                            Elephantidae is a taxonomic family, collectively elephants and mammoths. These are terrestrial large mammals with a trunk and tusks. Most genera and species in the family are extinct...

                            : modern elephants

Luo, Kielan-Jaworowska, and Cifelli classification

Several important fossil mammal discoveries have been made that have led researchers to question many of the relationships proposed by McKenna and Bell (1997). Additionally, researchers are subjecting taxonomic hypotheses to more rigorous cladistic analyses of early mammal fossils. Luo et al. (2002) summarized existing ideas and proposed new ideas of relationships among mammals at the most basal
Basal (phylogenetics)
In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...

 level. They argued that the term mammal should be defined based on characters (especially the dentary-squamosal jaw articulation) instead of a crown-based definition (the group that contains most recent common ancestor of monotreme
Monotreme
Monotremes are mammals that lay eggs instead of giving birth to live young like marsupials and placental mammals...

s and theria
Theria
Theria is a subclass of mammals that give birth to live young without using a shelled egg, including both eutherians and metatherians . The only omitted extant mammal group is the egg-laying monotremes....

ns and all of its descendants). Their definition of Mammalia is roughly equal to the Mammaliaformes
Mammaliaformes
Mammaliaformes is a clade that contains the mammals and their closest extinct relatives. Phylogenetically, it is defined as a clade including the most recent common ancestor of Sinoconodon, morganuconodonts, docodonts, Monotremata, Marsupialia, Placentalia, extinct members of this clade, and all...

  as defined by McKenna and Bell (1997) and other authors. They also define their taxonomic levels as clades and do not apply Linnean hierarchies.

Mammalia
  • Sinoconodon
    Sinoconodon
    Sinoconodon rigneyi is an ancient proto-mammal that appears in the fossil record in the late Triassic period, about 208 million years ago. Although the animal seems more related to Morganucodon than anything else, it differed substantially from other Mammaliaformes in its dental and growth habits...

    - earliest and most basal of mammals
  • Unnamed clade 1 - a clade that contains all other mammals. These are characterized by determinant growth and occlusal features of the cheek teeth.
    • †Morganucodontidae - morganucodontids, including †Morganucodon
      Morganucodon
      Morganucodon is an early mammalian genus which lived during the Late Triassic. It first appeared about 205 million years ago. This has also been identified with Eozostrodon. Unlike many other early mammals, Morganucodon is well represented by abundant and well preserved, though in the vast...

      , †Megazostrodon
      Megazostrodon
      Megazostrodon is an extinct Mammaliaform, widely accepted as being one of the first mammals, appearing in the fossil record approximately 200 million years ago...

      , and others
    • Docodonta
      Docodonta
      Docodonta is an order of extinct proto-mammals that lived during the mid- to late-Mesozoic era. Their most distinguishing physical features were their relatively sophisticated set of molars, from which the order gets its name. In the fossil record, Docodonta is represented primarily by isolated...

       - docodonts, including †Haldanodon and †Castorocauda (Ji et al., 2006)
    • Unnamed clade 2 - a clade containing all living mammals and some fossil relatives. It is characterized by the loss of a postdentary trough and a widened braincase.
      • Hadrocodium
        Hadrocodium
        Hadrocodium wui is an extinct basal mammal species that lived during the Lower Jurassic in what is now the Yunnan province of China...

      • Kuenotherium
      • Crown-group Mammalia - the group that contains most recent common ancestor of monotreme
        Monotreme
        Monotremes are mammals that lay eggs instead of giving birth to live young like marsupials and placental mammals...

        s and theria
        Theria
        Theria is a subclass of mammals that give birth to live young without using a shelled egg, including both eutherians and metatherians . The only omitted extant mammal group is the egg-laying monotremes....

        ns and all of its descendants. This group is defined by additional characters relating the occlusion of molar
        Molar (tooth)
        Molars are the rearmost and most complicated kind of tooth in most mammals. In many mammals they grind food; hence the Latin name mola, "millstone"....

        s and the presence of a well-developed masseteric fossa.
        • Australosphenida
          Australosphenida
          The Australosphenida are a clade of mammals. Today, living specimens exist only in Australia and New Guinea with only five surviving species, but fossils have been found in Madagascar and Argentina...

           - a clade that contains monotreme
          Monotreme
          Monotremes are mammals that lay eggs instead of giving birth to live young like marsupials and placental mammals...

          s and their fossil relatives. These fossils include †Ambondro
          Ambondro
          Ambondro is a town and commune in Madagascar. It belongs to the district of Ambovombe, which is a part of Androy Region. The population of the commune was estimated to be approximately 10,000 in 2001 commune census....

          , †Asfaltomylos
          Asfaltomylos
          Asfaltomylos is an extinct genus of Australosphenida from the middle Jurassic of Argentina. Only one species is recorded, Asfaltomylos patagonicus, from the Cañadon Asfalto Formation, Chubut Province, Patagonia.-References:...

          , †Ausktribosphenos
          Ausktribosphenos
          Ausktribosphenos is an extinct genus of Australosphenida from Early Cretaceous of Australia. The only recorded species, Ausktribosphenos nyktos, was found on Flat Rocks, Victoria.-References:...

          , and †Bishops. If correct, this clade represents an independent evolution of the tribosphenic molar in southern continents
          Gondwana
          In paleogeography, Gondwana , originally Gondwanaland, was the southernmost of two supercontinents that later became parts of the Pangaea supercontinent. It existed from approximately 510 to 180 million years ago . Gondwana is believed to have sutured between ca. 570 and 510 Mya,...

          .
        • Trechnotheria
          Trechnotheria
          Trechnotheria is a group of mammals that includes the therians and some fossil mammals from the Mesozoic Era. In the Jurassic through Cretaceous periods, the group was endemic to what would be Asia and Africa...

           - Theria
          Theria
          Theria is a subclass of mammals that give birth to live young without using a shelled egg, including both eutherians and metatherians . The only omitted extant mammal group is the egg-laying monotremes....

          ns, spalacotheriids and their relatives. They are characterized by features of the scapula
          Scapula
          In anatomy, the scapula , omo, or shoulder blade, is the bone that connects the humerus with the clavicle ....

          , tibia
          Tibia
          The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....

          , and humerus
          Humerus
          The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....

          .
          • †Spalacotheriidae - including Akidolestes
            Akidolestes
            Akidolestes cifellii is an extinct mammal which dates to the early Cretaceous period, 124.6 million years ago. It is part of the Yixian formation in Liaoning, China. The description is based on a nearly complete skeleton, partially complete skull, and an impression...

            , Zhangheotherium
            Zhangheotherium
            Zhangheotherium is a genus of symmetrodont, an extinct order of mammals. Previously known from only the tall pointed crowned teeth, Zhangheotherium, described from Liaoning Province, China, fossils in 1997, is the first symmetrodont known from a complete skeleton. It was dated to between 145-125...

            , and Maotherium
            Maotherium
            Maotherium was discovered in Early Cretaceous rocks in Liaoning Province, China, in 2003. Its scientific name means "Mao's beast" after the Chinese politician Mao Zedong. Maotherium belongs to an extinct group of Mesozoic mammals called symmetrodonts. Though little is known about this group, the...

            .
          • Cladotheria
            Cladotheria
            Cladotheria is a group of mammals that is defined as including the ancestor of Dryolestoidea, Peramuridae and Zatheria .-External links:* * -Further reading:Zofia Kielan-Jaworowska, Richard L...

             - Therians, dryolestids
            Dryolestidae
            Dryolestidae was an abundant and diverse group of Mesozoic mammals. These mammals were different from their relatives by having the following two characteristics:*Their upper and lower molars were shortened mesiodistally and widened labiolingually....

            , and their relatives. They are characterized by features of the tribosphenic molar and the angular process of the dentary.
            • Dryolestidae
              Dryolestidae
              Dryolestidae was an abundant and diverse group of Mesozoic mammals. These mammals were different from their relatives by having the following two characteristics:*Their upper and lower molars were shortened mesiodistally and widened labiolingually....

            • Amphitherium - incertae sedis
              Incertae sedis
              , is a term used to define a taxonomic group where its broader relationships are unknown or undefined. Uncertainty at specific taxonomic levels is attributed by , , and similar terms.-Examples:*The fossil plant Paradinandra suecica could not be assigned to any...

              (it may be a prototribosphenidan)
            • Prototribosphenida - Therians and fossil relatives including †Vincelestes
              Vincelestes
              Vincelestes is an extinct genus of actively mobile mammal, that lived in what would be South America during the Early Cretaceous from 130—112 mya, existing for approximately ....

              . Characterized by features of the cochlea
              Cochlea
              The cochlea is the auditory portion of the inner ear. It is a spiral-shaped cavity in the bony labyrinth, making 2.5 turns around its axis, the modiolus....

               including coiling.
              • Vincelestes
                Vincelestes
                Vincelestes is an extinct genus of actively mobile mammal, that lived in what would be South America during the Early Cretaceous from 130—112 mya, existing for approximately ....

              • Zatheria
                Zatheria
                Zatheria is a group of mammals that is defined as including the ancestor of Arguitheriidae, Arguimuridae, Vincelestidae, Peramuridae and Tribosphenida .-External links:* *...

                 - Therians and fossil relatives including the "peramurids". Characterized by the presence of wear in the talonid of the lower molars.
                • †"Peramuridae
                  Peramuridae
                  The family Peramuridae is a possible ancestor of early therians. The only certain representative lived in the Late Jurassic and Early Cretaceous.-References:*...

                  " - †Peramus and relatives. Known only from preserved mandibles and distinctly zatherian molars.
                • Boreosphenida - Therians and fossil relatives including †Kielantherium. They are characterized by molar features.
                  • Kielantherium
                  • Deltatheroida
                    Deltatheroida
                    Deltatheroida is an extinct group of basal metatherians that lived in the Cretaceous and were closely related to marsupials. Their fossils are restricted to Central Asia and North America...

                     including †Deltatheridium
                    Deltatheridium
                    Deltatheridium is an extinct species of metatherian. It lived in what is now Mongolia during the Upper Cretaceous. It was a basal metatherian, which places it near start of the linage that led to the marsupials, such the kangaroo, koala, and opossum.It had a length of...

                    - incertae sedis (it may represent a metatherian)
                  • Crown-group Theria
                    Theria
                    Theria is a subclass of mammals that give birth to live young without using a shelled egg, including both eutherians and metatherians . The only omitted extant mammal group is the egg-laying monotremes....

                     - the group that contains most recent common ancestor of marsupial
                    Marsupial
                    Marsupials are an infraclass of mammals, characterized by giving birth to relatively undeveloped young. Close to 70% of the 334 extant species occur in Australia, New Guinea, and nearby islands, with the remaining 100 found in the Americas, primarily in South America, but with thirteen in Central...

                    s and placentals and all of its descendants. Characterized by a host of molar features, aspects of the alispenoid, and aspects of the astragalus
                    Talus bone
                    -External links:* *...

                     region.
        • Eutriconodonta
          Eutriconodonta
          Eutriconodonta is a order of early mammals. Eutriconodonts existed in Asia, Europe, North and South America during the Jurassic and the Cretaceous periods. The order was named by Kermack et al. in 1973 as a replacement name for the paraphyletic Triconodonta....

           - incertae sedis. Triconodonts appear to be a member of the crown-Mammalia clade, but their relationships within it are unknown. It is also not certain that they represent a monophyletic
          Monophyly
          In common cladistic usage, a monophyletic group is a taxon which forms a clade, meaning that it contains all the descendants of the possibly hypothetical closest common ancestor of the members of the group. The term is synonymous with the uncommon term holophyly...

           group. Examples include Repenomamus
          Repenomamus
          Repenomamus is the largest mammal known from the Cretaceous period of Manchuria, and it is the mammal for which there is the best evidence that it fed on dinosaurs. It is not possible to determine if Repenomamus actively hunted live dinosaurs or scavenged dead dinosaurs.-Paleobiology:Repenomamus...

          .
      • Multituberculata
        Multituberculata
        The Multituberculata were a group of rodent-like mammals that existed for approximately one hundred and twenty million years—the longest fossil history of any mammal lineage—but were eventually outcompeted by rodents, becoming extinct during the early Oligocene. At least 200 species are...

        - incertae sedis. Luo e al. (2002) argue that multituberculates cannot be confidently placed in a particular clade of mammals. They suggest that they represent either basal mammals or are sister to the Trechnotheria.

Simplified classification for non-specialists

The following classification is a simplified version based on current understanding suitable for non-specialists who want to understand how living genera are related to each other. The classification ignores differences in levels and thus cannot be used to estimate the respective distances between taxa. It also ignores taxa that became extinct in pre-historic times. Finally, English names are preferred whenever they exist. This makes it especially suited for non-specialists who wish to gain an easy overview. For the full picture, the non-simplified versions above should be consulted.
  • Monotremes (prototheria): echidnas and platypus
    • Platypus
    • Echidnas (tachyglossids)
  • Live-bearing mammals (theria)
    • Marsupials
      • Australodelphia: Australian marsupials and monito del Monte
        • Monito del Monte
        • Dasyuromorphs
          • Dasyurids: antechinuses, quolls, dunnarts, Tasmanian devil, and allies
          • Numbat
        • Peramelemorphs: bilbies and bandicoots
          • Bilbies (thylacomyids)
          • Bandicoots (peramelids)
        • Marsupial moles (notoryctids)
        • Diprotodonts
          • Koala
          • Wombats (vombatids)
          • Phalangerids: brushtail possums and cuscuses
          • Pygmy possums (burramyids)
          • Honey possum
          • Petaurids: striped and Leadbeater's possums, and yellow-bellied, suger, mahogany and squirrel glider
          • Ringtailed possums (pseudocheirids)
          • Potorids: potoroos, rat kangaroos and bettongs
          • Acrobatids: feathertail glider and feather-tailed possum
          • Musky rat-kangaroo
          • Macropodids: kangaroos, wallabies and allies
      • Ameridelphia: New World marsupials except monito del Monte
        • Opossums (didelphids)
        • Shrew opossums (caenolestids)
    • Placentals
      • Atlantic placentals (atlantogenatans)
        • Afroplacentals (afrotherians)
          • Afroinsectiphilians: elephant shrews, tenrecs, otter shrews, golden moles, and aardvark
            • Elephant shrews (macroscelidids)
            • Afrosoricids: tenrecs and golden moles
              • Tenrecids: tenrecs and otter shrews
              • Golden moles (chrysochlorids)
            • Aardvark
          • Paenungulates: hyraxes, elephants, dugongs and manatees
            • Hyraxes or dassies (procaviids)
            • Elephants (elephantids)
            • Sirenians: dugong and manatees
              • Dugong
              • Manatees (trichechids)
        • Xenarthrans
          • Pilosans: sloths and anteaters
            • Anteaters (vermilinguans)
              • Silky anteater
              • Myrmecophagids: giant anteater and tamanduas
            • Sloths (folivorans)
              • Three-toed sloths (bradypodids)
              • Two-toed sloths (megalonychids)
          • Armadillos (dasypodids)
      • Northern placentals (boreoeutherians)
        • Supraprimates (euarchontoglires)
          • Euarchontans: treeshrews, colugos and primates
            • Treeshrews (scandentians)
              • Tupaiids: all treshrews except pen-tailed
              • Pen-tailed treeshrew
            • Colugos or flying lemurs (cynocephalids)
            • Primates
              • Strepsirrhines: lemur- and loris-like primates
                • Lemur-like primates (lemuriforms)
                  • Cheirogaleids: dwarf lemurs and mouse-lemurs
                  • Aye-aye
                  • True lemurs (lemurids)
                  • Sportive lemurs (lepilemurids)
                  • Indriids: woolly lemurs and allies
                • Loris-like primates (lorisiforms)
                  • Lorisids: lorises, pottos and allies
                  • Galagos (galagids)
              • Haplorhines: tarsiers, monkeys and apes
                • Tarsiers (tarsiids)
                • Anthropoid primates
                  • New World monkeys (platyrrhines)
                    • Callitrichids: marmosets and tamarins
                    • Cebids: capuchins and squirrel monkeys
                    • Aotids: night or owl monkeys
                    • Pitheciids: titis, sakis and uakaris
                    • Atelids: howler, spider, woolly spider, and woolly monkeys
                  • Catarrhines
                    • Old World monkeys (cercopithecids)
                    • Hominoid primates
                      • Gibbons (hylobatids)
                      • Great apes (hominids): incl. Humans
          • Glires: pikas, rabbits, hares, and rodents
            • Lagomorphs: pikas, rabits and hares
              • Leporids: rabbits and hares
              • Pikas (ochotonids)
            • Rodents
              • Anomalure-like rodents (anomaluromorphs): Scaly-tailed squirrels and springhares
                • Scaly-tailed squirrels or anomalures (anomalurids)
                • Springhares (pedetids)
              • Beaver-like rodents (castorimorphs)
                • Beavers (castorids)
                • Gopher-like rodents (geomyoid rodents)
                  • Pocket or true gophers (geomyids)
                  • Heteromyids: kangaroo rats and kangaroo mice
              • Porcupine-like rodents (hystricomorphs)
                • Laotian rock rat
                • Gundis (ctenodactylids)
                • Hystricognaths
                  • African mole rats (bathyergids)
                  • Old World porcupines (hystricids)
                  • Dassie rat
                  • Cane rats (thryonomyids)
                  • Cavy-like rodents (caviomorphs)
                    • Chinchilla rats (abrocomids)
                    • Hutias (capromyids)
                    • Cavies (caviids): incl. Guinea pigs and capybara
                    • Chinchillids: chinchillas and viscachas
                    • Tuco-tucos (ctenomyids)
                    • Agoutis (dasyproctids)
                    • Pacas (cuniculids)
                    • Pacarana
                    • Spiny rats (echymyids)
                    • New World porcupines (erethizontids)
                    • Myocastorids: nutria and coypu
                    • Octodonts (octodontids): Andean rock-rats, degus and viscacha-rats
              • Mouse-like rodents (myomorphs)
                • Dipodids: jerboas and jumping mice
                • Muroid rodents
                  • Mouse-like hamsters (calomyscids)
                  • Cricetids: hamsters, New World rats and mice, voles
                  • Murids: true mice and rats, gerbils, spiny mice, crested rat
                  • Nesomyids: climbing mice, rock mice, white-tailed rat, Malagasy rats and mice
                  • Spiny doormice (platacanthomyids)
                  • Spalacids: mole rats, bamboo rats, and zokors
              • Squirrel-like rodents (sciuromorphs)
                • Mountain beaver
                • Doormice (glirids)
                • Squirrels (sciurids): incl. chipmunks, prairie dogs, and marmots
        • Laurasian placentals (laurasiatherians)
          • Hedgehogs (erinaceids)
          • Soricomorphs: moles, shrews, solenodons
            • Shrews (soricids)
            • Moles (talpids)
            • Solenodons (solenodontids)
          • Ferungulates: ungulates, cetaceans, bats, pangolins and carnivorans
            • Cetartiodactyls: camels, swine, cetaceans, hippos, and ruminants
              • Camelids: camels and llamas
              • Swine (suinans): pigs and peccaries
                • Pigs (suids)
                • Peccaries (tayassuids)
              • Cetruminantians: cetaceans hippos and ruminants
                • Cetancodonts: Cetaceans and hippos
                  • Cetaceans: Whales, dolphins and porpoises
                    • Baleen whales (mysticetes)
                      • Balaenids: right whales and bowhead whale
                      • Rorquals (balaenopterids)
                      • Gray whale
                      • Pygmy right whale
                    • Toothed whales (odontocetes)
                      • Dolphins (delphinids)
                      • Monodontids: beluga and narwhal
                        • Beluga
                        • Narwhal
                      • Porpoises (phocoenids)
                      • Sperm whale
                      • Kogiids: pygmy and dwarf sperm whale
                      • River dolphins (platanistoid whales)
                        • Iniids: Amazon and Bolivian river dolphin
                        • La Plata dolphin
                        • Platanistids: Ganges and Indus river doplhins
                      • Beaked whales (ziphids)
                  • Hippos (hippopotamids)
                • Ruminantiamorphs: chevrotains, pronghorn, giraffes, musk deer, deer, and bovids
                  • Chevrotains (tragulids)
                  • Pecorans
                    • Pronghorn
                    • Giraffids: giraffe and okapi
                    • Musk deer (moschids)
                    • Deer (cervids)
                    • Bovids: cattle, goats, sheep and antelope
            • Pegasoferans: bats, odd-toed ungulates, pangolins and carnivorans
              • Bats (chiropterans)
                • Megabats (pteropodids)
                • Microbats (microchiropterans)
                  • Sac-winged or sheath-tailed bats (emballonurids)
                  • Rhinopomatoid bats
                    • Mouse-tailed bats (rhinopomatids)
                    • Bumblebee bat or Kitti's hog-nosed bat
                  • Rhinolophoid bats
                    • Horseshoe bats (rhinolophids)
                    • Hollow-faced or slit-faced bats (nycterids)
                    • False vampires (megadermatids)
                  • Vesper bats or evening bats (vespertilionids)
                  • Molossoid bats
                    • Free-tailed bats (molossids)
                    • Pallid bats (antrozoids)
                  • Nataloid bats
                    • Funnel-eared bats (natalids)
                    • Sucker-footed bats (myzopodids)
                    • Disc-winged bats (thyropterids)
                    • Smoky bats (furipterids)
                  • Noctilionoid bats
                    • Bulldog or fisherman bats (noctilionids)
                    • New Zealand short-tailed bats (mystacinids)
                    • Ghost-faced or moustached bats (mormoopids)
                    • Leaf-nosed bats (phyllostomids)
              • Zooamatans: odd-toed ungulates, pangolins and carnivorans
                • Odd-toed ungulates (perissodactyls)
                  • Horses (equids)
                  • Ceratomorphs
                    • Tapirs (tapirids)
                    • Rhinoceroses (rhinocerotids)
                • Ferans
                  • Pangolins or scaly anteaters (manids)
                  • Carnivorans
                    • Cat-like carnivorans (feliforms)
                      • African palm civet
                      • Feloid carnivorans
                        • Asiatic linsangs (prionodontids)
                        • Cats (felids)
                      • Viverroid carnivorans
                        • Viverrids: civets and allies
                        • Herpestoid carnivorans
                          • Hyaenids: hyenas and aardwolf
                          • Malagasy carnivorans (euplerids)
                          • Herpestids: mongooses and allies
                    • Dog-like carnivorans (caniforms)
                      • Canids: dogs and allies
                      • Arctoid carnivorans
                        • Bears (ursids)
                        • Musteloid carnivorans
                          • Red panda
                          • Mephitids: skunks and stink badgers
                          • Mustelids: weasels, martens, badgers, wolverines, minks, ferrets and otters
                          • Procyonids: raccoons and allies
                        • Pinnipeds
                          • Walrus
                          • Otariids: sea lions, eared seals, fur seals
                          • True seals (phocids)
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