Taxonomic rank

The level, for nomenclatural purposes, of a taxon in a taxonomic hierarchy (e.g.

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Encyclopedia

Taxonomic rank, taxonomic category, rank, or category is an abstract term used in the scientific classification

Scientific classification

Biological classification or scientific classification in biology, is a method by which biologists group and categorize species of organisms....
, or taxonomy

Taxonomy

Taxonomy is the practice and science of classification. The word comes from the Greek language ', taxis and ', nomos .Taxonomies, or taxonomic schemes, are composed of taxonomic units known as taxa , or kinds of things that are arranged frequently in a hierarchical structure....
, of organisms. Taxonomic rank indicates the level of a taxon

Taxon

A taxon or taxonomic unit is a name designating an organism or a group of organisms. In biological nomenclature according to Carl Linnaeus, a taxon is assigned a taxonomic rank and can be placed at a particular level in a systematic hierarchy reflecting evolutionary relationships....
 in the taxonomic hierarchy. Taxa ranked at a particular taxonomic rank are groupings of organism

Organism

In biology, an organism is any life thing . In at least some form, all organisms are capable of response to stimulus , reproduction, growth and developmental biology, and maintenance of homeostasis as a stable whole....
s at the same classification level.

The International Code of Zoological Nomenclature

International Code of Zoological Nomenclature

The International Code of Zoological Nomenclature is a set of rules in zoology that have one fundamental aim: to provide the maximum universality and continuity in the naming of all animals according to taxonomy judgment....
 defines rank, in the taxonomic sense, as:

The level, for nomenclatural purposes, of a taxon in a taxonomic hierarchy (e.g. all families are for nomenclatural purposes at the same rank, which lies between superfamily and subfamily). The ranks of the family group, the genus group, and the species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring....
 group at which nominal taxa may be established are stated in Articles 10.3, 10.4, 35.1, 42.1 and 45.1. — International Commission on Zoological Nomenclature (1999) International Code of Zoological Nomenclature. Fourth Edition. - International Trust for Zoological Nomenclature, XXIX + 306 pp.

Main taxonomic ranks

Carl Linnaeus devised Linnaean taxonomy

Linnaean taxonomy

Linnaean taxonomy is a method of classifying living things, originally devised by Carolus Linnaeus , although it has changed considerably since his time....
 using a ranking scale: kingdom, class, order, genus, species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring....
, and variety.

Today, nomenclature is regulated by the Nomenclature Codes

Nomenclature Codes

The Nomenclature Codes are the rulebooks that govern biological nomenclature.After the successful introduction of two-part names for species by Carolus Linnaeus it became ever more apparent that a detailed body of rules was necessary to govern scientific names....
, which allow names divided into exactly defined ranks. Despite this there are slightly different ranks for zoology and for botany.

There are eight main taxonomic ranks: domain, kingdom, phylum or division¹, class, order, family, genus, species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring....
.

Notes to table: ¹ Phylum is used in zoology. It is at the same level as division in botany.
² Preferred to phylum in botany, that is accounted as identical.

In zoology

Zoology

Zoology is the branch of biology concerned with the study of animals. The most common pronunciation of "zoology" is ; however, an alternative pronunciation is ....
 and in botanical nomenclature

Botanical nomenclature

Botanical nomenclature is the formal naming of plants, from a scientific point of view. It has a long history, going back perhaps to Theophrastos, but anyway back to the period when Latin was the scientific language throughout Europe....
, a taxon is usually assigned to a taxonomic rank in a hierarchy. The basic rank is that of species, and if an organism is named it most often will receive a species name. The next most important rank is that of genus

Genus

A genus is a low-level taxonomic rank used in the classification of living and fossil organisms. The taxonomic ranks are domain , kingdom , phylum, class , order , family , genus, and species....
: if an organism is given a species name it will at the same time be assigned to a genus, as the genus name is part of the species name. The third-most important rank, although it was not used by Linnaeus, is that of family

Family (biology)

In biological classification, family is a taxonomic rank. Exact details of formal nomenclature depend on the Nomenclature Codes which applies....
.

A binomial is a two-word name which is used to describe a particular species. For example, the binomial name for a human is Homo sapiens. This is italicised when typing, and underlined when writing. The first word refers to the genus, which is a broad grouping of closely related species, and is capitalized. The second word, in lower case, always indicates the species to which the organism is assigned within its genus.

Ranks in zoology

There are definitions of the following taxonomic ranks in the International Code of Zoological Nomenclature

International Code of Zoological Nomenclature

The International Code of Zoological Nomenclature is a set of rules in zoology that have one fundamental aim: to provide the maximum universality and continuity in the naming of all animals according to taxonomy judgment....
: superfamily, family, subfamily, tribe, subtribe, genus, subgenus, species, subspecies.

The International Code of Zoological Nomenclature

International Code of Zoological Nomenclature

The International Code of Zoological Nomenclature is a set of rules in zoology that have one fundamental aim: to provide the maximum universality and continuity in the naming of all animals according to taxonomy judgment....
 divides names into "family-group names", "genus-group names" and "species-group names". The Code explicitly mentions:

superfamily

family

Family

Family denotes a group of people affiliated by a common ancestry, affinity or co-residence. Although the concept of consanguinity originally referred to relations by "blood," some cultural anthropology have argued that one must understand the idea of "blood" metaphorically, and that many societies understand 'family' through other concepts r...

subfamily

tribe

Tribe (biology)

In biology, a tribe — or infrafamily — is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes....

subtribe

genus

Genus

A genus is a low-level taxonomic rank used in the classification of living and fossil organisms. The taxonomic ranks are domain , kingdom , phylum, class , order , family , genus, and species....

subgenus

Subgenus

In biology, a subgenus is a taxonomic rank directly below genus. See rank and rank .In ICZN, a subgeneric name can be used independently or included in a binomen, in parentheses, placed between the name of a biological genus and specific name: e.g....

superspecies

Superspecies

Superspecies is a group of at least two more or less distinctive species with approximately parapatric distributions. Not all cryptic species complexes are superspecies, and vice versa, but many are....

species

subspecies

The rules in the Code apply to the ranks of superfamily to subspecies, and only to some extent to those above the rank of superfamily. In the "genus group" and "species group" no further ranks are allowed. Among zoologists, additional ranks such as species group, species subgroup, species complex and superspecies are sometimes used for convenience as extra, but unofficial, ranks between the subgenus

Subgenus

In biology, a subgenus is a taxonomic rank directly below genus. See rank and rank .In ICZN, a subgeneric name can be used independently or included in a binomen, in parentheses, placed between the name of a biological genus and specific name: e.g....
 and species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring....
 levels in taxa with many species (e.g., the genus

Genus

A genus is a low-level taxonomic rank used in the classification of living and fossil organisms. The taxonomic ranks are domain , kingdom , phylum, class , order , family , genus, and species....
 Drosophila

Drosophila

Drosophila is a genus of small fly, belonging to the family Drosophilidae, whose members are often called "fruit flies" or more appropriately pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species to linger around overripe or rotting fruit....
).

Ranks of taxa at lower levels may be denoted in their groups by adding the prefix "infra," meaning lower, to the rank. For example infraspecies or infrasubspecies. Infraspecific taxa then include all divisions of the species into subspecies or lower taxa.

Names of zoological taxa

• A taxon above the rank of species gets a scientific name in one part (a uninominal name)
• A species (a taxon at the rank of species) gets a name composed of two names (a binominal name or binomen
  Binomen
  
  In ICZN, a binomen, or binominal name, is the name of a species. The term was introduced in 1953.A binomen is a name consisting of two names: generic name and specific name....
   : generic name
  Generic name
  
  Generic name may be:*Generic name, name of a biological genus*Generic name, International Nonproprietary Name for a drug*A placeholder name, referring to nobody in particular, such as Joe Bloggs or John Q. Public...
   + specific name
  Specific name
  
  In zoological nomenclature, a specific name or specific epithet is the second part in the name of a species . The first part is the name of the genus....
  ; for example Panthera leo)
• A subspecies (a taxon at the rank of subspecies) gets a name composed of three names (a trinominal name or trinomen
  Trinomen
  
  In ICZN, a trinomen, or trinominal name, refers to the name of a subspecies.A trinomen is a name consisting of three names: Genus#Generic name, specific name and subspecific name....
   : generic name
  Generic name
  
  Generic name may be:*Generic name, name of a biological genus*Generic name, International Nonproprietary Name for a drug*A placeholder name, referring to nobody in particular, such as Joe Bloggs or John Q. Public...
   + specific name
  Specific name
  
  In zoological nomenclature, a specific name or specific epithet is the second part in the name of a species . The first part is the name of the genus....
   + subspecific name
  Subspecific name
  
  In ICZN, a subspecific name is the third part of a trinomen. In zoology there is only one rank below that of species, namely "subspecies".The name of a subspecies is a trinomen, a trinomial name, i.e....
  ; for example Felis silvestris catus, the house cat
  Cat
  
  The cat , also known as the Domestication cat or house cat to distinguish it from other Felinae and Felidae, is a small predationy carnivore species of crepuscular mammal that is valued by humans for its companionship and its ability to hunt vermin, snakes, scorpions, and other unwanted household pests....
  ). As there is only one rank below that of species, no connecting term to indicate rank is used.

Ranks in botany

There are definitions of the following taxonomic ranks in the International Code of Botanical Nomenclature

International Code of Botanical Nomenclature

The International Code of Botanical Nomenclature is the set of rules and recommendations dealing with the formal botanical names that are given to plants....
: kingdom (regnum), subregnum, division or phylum (divisio, phylum), subdivisio or subphylum, class (classis), subclassis, order (ordo), subordo, family (familia), subfamilia, tribe (tribus), subtribus, genus (genus), subgenus, section (sectio), subsectio, series (series), subseries, species (species), subspecies, variety (varietas), subvarietas, form (forma), subforma.

There are definitions of following taxonomic ranks in International Code of Nomenclature for Cultivated Plants

International Code of Nomenclature for Cultivated Plants

The International Code of Nomenclature for Cultivated Plants regulates the naming of cultivars, cultivar Groups and graft-chimaeras. Examples are...
: cultivar group, cultivar.

According to Art 3.1 of the ICBN the most important ranks of taxa are: kingdom, division or phylum, class, order, family, genus, and species. According to Art 4.1 the secondary ranks of taxa are tribe, section, series, variety and form. There is an indeterminate number of ranks. The ICBN explicitly mentions: primary ranks

secondary ranks

further ranks kingdom (regnum) subregnum

division or phylum (divisio, phylum) subdivisio or subphylum

class (classis) subclassis

order (ordo) subordo

family (familia) subfamilia

tribe (tribus)

subtribus

genus (genus) subgenus

section (sectio)

subsectio

series (series)

subseries

species (species) subspecies

variety (varietas)

subvarietas

form (forma)

subforma

The rules in the ICBN apply primarily to the ranks of family and below, and only to some extent to those above the rank of family. Also see descriptive botanical names

Descriptive botanical names

Descriptive botanical names: Article 16 of the ICBN rules that a name above the rank of rank may be either descriptive or formed from the name of an included family....
.

Names of botanical taxa

Of the botanical names used by Linnaeus

Carolus Linnaeus

Carl Linnaeus was a Sweden botanist, physician, and zoologist, who laid the foundations for the modern scheme of binomial nomenclature. He is known as the father of modern alpha taxonomy, and is also considered one of the fathers of modern ecology....
 only names of genera, species and varieties are still used.

Taxa at the rank of genus and above get a botanical name

Botanical name

A botanical name is a formal scientific name conforming to the International Code of Botanical Nomenclature and, if the plant is a cultigen, the additional cultivar and/or Group epithets must conform to the International Code of Nomenclature for Cultivated Plants....
 in one part (unitary name); those at the rank of species and above (but below genus) get a botanical name in two parts (binary name); all taxa below the rank of species get a botanical name in three parts (ternary name

Ternary name

In botanical nomenclature, the ICBN prescribes a "three part name" for any taxon below the rank of species. The ranks below that of species explicitly allowed in the ICBN are...
).

For hybrids, getting a hybrid name

Hybrid name

In botanical nomenclature, a Hybrid may be given a hybrid name, which is a special kind of botanical name. The ICBN provides the following options in dealing with a hybrid:...
, the same ranks apply, preceded by "notho", with nothogenus as the highest permitted rank.

Examples

The usual classifications of five species follow: the fruit fly

Drosophila melanogaster

Drosophila melanogaster is a two-winged insect that belongs to the Diptera, the Order of the Fly. The species is commonly known as the Drosophilidae or vinegar fly, and is one of the most commonly used model organisms in biology, including studies in genetics, physiology and Life history theory....
 so familiar in genetics laboratories (Drosophila melanogaster), human

Human

A human being, also human or man, is a member of a species of bipedalism primates in the family Hominidae . Mitochondrial DNA evidence indicates that modern humans originated in east Africa about 200,000 years ago....
s (Homo sapiens), the pea

Pea

A pea is most commonly the small spherical seed or the seed-pod of the legume Pisum sativum. Each pod contains several peas. Although treated as a vegetable in cooking, it is botanically a fruit....
s used by Gregor Mendel

Gregor Mendel

Gregor Johann Mendel was an Augustinians priest and scientist, and is often called the father of genetics for his study of the biological inheritance of certain Trait s in pea plants....
 in his discovery of genetics

Genetics

Genetics , a discipline of biology, is the science of heredity and Genetic variation in living organisms. The fact that living things inherit traits from their parents has been used since prehistoric times to improve crop plants and animals through selective breeding....
 (Pisum sativum), the "fly agaric" mushroom Amanita muscaria

Amanita muscaria

Amanita muscaria, commonly known as the fly agaric or fly Amanita, is a poisonous and psychoactive basidiomycete fungus, one of many in the genus Amanita....
, and the bacterium Escherichia coli

Escherichia coli

'Escherichia coli' , is a Gram negative bacterium that is commonly found in the lower gastrointestinal tract of warm-blooded animals. Most E....
. The eight major ranks are given in bold; a selection of minor ranks are given as well.

Table Notes:

• The ranks of higher taxa, especially intermediate ranks, are prone to revision as new information about relationships is discovered. For example, the traditional classification of primates (class Mammalia — subclass Theria — infraclass Eutheria — order Primates) has been modified by new classifications such as McKenna and Bell (class Mammalia — subclass Theriformes — infraclass Holotheria) with Theria and Eutheria assigned lower ranks between infraclass and the order Primates. See mammal classification
  Mammal classification
  
  Mammalia is a class of animal within the Phylum Chordata. Mammal classification has been through several iterations since Carolus Linnaeus initially defined the class....
   for a discussion. These differences arise because there are only a small number of ranks available and a large number of branching points in the fossil record.
• Within species further units may be recognised. Animals may be classified into subspecies
  Subspecies
  
  In biology, subspecies is the taxonomic rank immediately subordinate to a species. A subspecies is a taxonomic group which is less distinct than the Common descent or species from which it originates....
   (for example, Homo sapiens sapiens, modern humans) or morph
  Polymorphism (biology)
  
  Polymorphism in biology occurs when two or more clearly different phenotypes exist in the same population of a species ? in other words, the occurrence of more than one form or morph....
  s (for example Corvus corax varius morpha leucophaeus, the Pied Raven). Plants may be classified into subspecies (for example, Pisum sativum subsp. sativum, the garden pea) or varieties (for example, Pisum sativum var. macrocarpon, snow pea), with cultivated plants getting a cultivar
  Cultivar
  
  A cultivar is a cultivated plant that has been selected and given a unique name because of its decorative or useful characteristics; it is usually distinct from similar plants and when Plant propagation it retains those characteristics....
   name (for example, Pisum sativum var. macrocarpon 'Snowbird'). Bacteria may be classified by strains
  Strain (biology)
  
  In biology, strain is a low-level taxonomic rank used in three related ways....
   (for example Escherichia coli O157:H7
  Escherichia coli O157:H7
  
  Escherichia coli O157:H7 is an enterohemorrhagic strain of the Bacteria Escherichia coli and a cause of foodborne illness. Infection often leads to bloody diarrhea, and occasionally to kidney failure, especially in young children and elderly people....
  , a strain that can cause food poisoning
  Foodborne illness
  
  Foodborne illness is any illness resulting from the consumption of food.There are two types of food poisoning: food infection and food intoxication....
  ).
• A mnemonic for remembering the order of the taxa is: Do Koalas Prefer Chocolate Or Fruit, Generally Speaking? Another easy one is Damn, Kinky People Can Often Find Great Sex. Another, less prosaic old favourite, is Dear King Philip Came Over For Great Sex. There is also the Greek
  Greeks
  
  The Greeks , also known as Hellenes, are a nation and ethnic group native to Greece, Cyprus and neighbouring regions, who can also be found in Greek diaspora communities around the world....
   favourite, Dear King Philippos Came Over For Greek Souvlaki
  Souvlaki
  
  Souvlaki or souvlakia is a popular Greek cuisine fast food consisting of small pieces of meat and sometimes vegetables grilled on a skewer....
  . Another popular one is Daring King Philip Craps On Families That Gain Superpowers.
• Other mnemonic
  Mnemonic
  
  A mnemonic device is a memory aid. Commonly met mnemonics are often verbal, something such as a very short poem or a special word used to help a person remember something, particularly lists, but may be visual, kinesthetic or auditory....
  s are available at and.

Terminations of names

Taxa

Taxon

A taxon or taxonomic unit is a name designating an organism or a group of organisms. In biological nomenclature according to Carl Linnaeus, a taxon is assigned a taxonomic rank and can be placed at a particular level in a systematic hierarchy reflecting evolutionary relationships....
 above the genus level are often given names based on the type genus

Type genus

In biology, the phrase type genus is used differently depending on the nomenclature Codes that applies:* In ICZN, a type genus is "The nominal genus that is the name-bearing Biological type of a nominal family-group taxon."...
, with a standard termination. The terminations used in forming these names depend on the kingdom, and sometimes the phylum and class, as set out in the table below.

Table notes:

• In botany and mycology names at the rank of family and below are based on the name of a genus, sometimes called the type genus
  Type genus
  
  In biology, the phrase type genus is used differently depending on the nomenclature Codes that applies:* In ICZN, a type genus is "The nominal genus that is the name-bearing Biological type of a nominal family-group taxon."...
   of that taxon, with a standard ending. For example, the rose family Rosaceae
  Rosaceae
  
  The Rosaceae or rose family is a large family of plants, with about 3,000-4,000 species in 100-160 genera. Traditionally it has been divided into four subfamilies: Rosoideae, Spiraeoideae, Maloideae, and Amygdaloideae....
   is named after the genus Rosa, with the standard ending "-aceae" for a family. Names above the rank of family are formed from a family name, or are descriptive (like Gymnosperm
  Gymnosperm
  
  Gymnosperm is a group of spermatophyte seed-bearing plants with ovules on scales, which are usually arranged in cone-like structures. The other major group of seed-bearing plants, the angiosperms, [from the Greek, 'angion' - container] have ovules enclosed in a carpel, a sporophyll with fused margins....
  ae or Fungi
  Fungus
  
  A fungus is a Eukaryote organism that is a member of the Kingdom Fungi . The fungi are a monophyletic group, also called the Eumycota , that is phylogeny distinct from the morphologically similar slime molds and water molds ....
  ).
• For animals, there are standard suffixes for taxa only up to the rank of superfamily.
• Forming a name based on a generic name may be not straightforward. For example, the Latin
  Latin
  
  Latin is an Italic language, historically spoken in Latium and Ancient Rome. Through the Military history of the Roman Empire, Latin spread throughout the Mediterranean and a large part of Europe....
   "homo" has the genitive "hominis", thus the genus "Homo" (human) is in the Hominidae, not "Homidae".
• The ranks of epifamily, infrafamily and infratribe (in animals) are used where the complexities of phyletic branching require finer-than-usual distinctions. Although they fall below the rank of superfamily, they are not regulated under the International Code of Zoological Nomenclature and hence do not have formal standard endings. The suffixes listed here are regular, but informal.

All taxonomic ranks

The following table lists all taxonomic ranks including those which are not in use today and those which are identical with other ranks.

All taxonomic ranks
Latin	English	Notes
	superdomain Domain (biology) In Biology taxonomy, a domain is the highest taxonomic rank of organisms, higher than a Kingdom . According to the three-domain system of Carl Woese, introduced in 1990, the Tree of life consists of three domains: Archaea, Bacteria and Eukaryota....
regio	domain Domain (biology) In Biology taxonomy, a domain is the highest taxonomic rank of organisms, higher than a Kingdom . According to the three-domain system of Carl Woese, introduced in 1990, the Tree of life consists of three domains: Archaea, Bacteria and Eukaryota....
	subdomain Subdomain In the Domain Name System hierarchy, a subdomain is a domain name that is part of a larger domain. For example, "mail.example.com" and "calendar.example.com" are subdomains of the "example.com" domain, which in turn is a subdomain of the "com" top-level domain ....
	infradomain
imperium	empire Empire Empire derives from the Latin word imperium, denoting ?military command? in Roman. Politically, an empire is a geographically extensive group of states and peoples united and ruled either by a monarch or an oligarchy....
superregnum	superkingdom Domain (biology) In Biology taxonomy, a domain is the highest taxonomic rank of organisms, higher than a Kingdom . According to the three-domain system of Carl Woese, introduced in 1990, the Tree of life consists of three domains: Archaea, Bacteria and Eukaryota....
	suprakingdom
	midkingdom
regnum	kingdom Kingdom (biology) In Biology taxonomy, kingdom or regnum is a taxonomic rank in either the highest rank, or the Rank below domain . Each kingdom is divided into smaller groups called Phylum ....
subregnum	subkingdom Kingdom (biology) In Biology taxonomy, kingdom or regnum is a taxonomic rank in either the highest rank, or the Rank below domain . Each kingdom is divided into smaller groups called Phylum ....
	interkingdom
	branch Branch A branch or tree branch is a woody structural Limb connected to but not part of the central trunk of a tree . Large branches are known as boughs and small branches are known as twigs.....
	infrakingdom
superphylum	superphylum Phylum A phylum "Phylum" is adopted from the Greek phylai, the clan-based voting groups in Greek city-states. is a taxonomic rank below Kingdom and above Class ....
	supraphylum
	midphylum
phylum	phylum Phylum A phylum "Phylum" is adopted from the Greek phylai, the clan-based voting groups in Greek city-states. is a taxonomic rank below Kingdom and above Class ....
subphylum	subphylum Subphylum In life, a subphylum is a taxonomic rank intermediate between phylum and superclass . The rank of subdivision in plants and fungi is equivalent to subphylum....
infraphylum	infraphylum
divisio	division1
subdivisio	subdivision Subphylum In life, a subphylum is a taxonomic rank intermediate between phylum and superclass . The rank of subdivision in plants and fungi is equivalent to subphylum.... 1
claudius	claudius
superclassis	superclass Class (biology) A class is the taxonomic rank in the biological classification of organisms in biology below phylum and above Order .The orders of taxonomy are life, Domain , kingdom , phylum, class , order , family , genus, and species....
	grade
classis	class Class (biology) A class is the taxonomic rank in the biological classification of organisms in biology below phylum and above Order .The orders of taxonomy are life, Domain , kingdom , phylum, class , order , family , genus, and species....
subclassis	subclass Class (biology) A class is the taxonomic rank in the biological classification of organisms in biology below phylum and above Order .The orders of taxonomy are life, Domain , kingdom , phylum, class , order , family , genus, and species....
	infraclass Class (biology) A class is the taxonomic rank in the biological classification of organisms in biology below phylum and above Order .The orders of taxonomy are life, Domain , kingdom , phylum, class , order , family , genus, and species....
parvclassis	parvclass Class (biology) A class is the taxonomic rank in the biological classification of organisms in biology below phylum and above Order .The orders of taxonomy are life, Domain , kingdom , phylum, class , order , family , genus, and species....
superdivisio	superdivision2
divisio	division2
subdivisio	subdivision Subphylum In life, a subphylum is a taxonomic rank intermediate between phylum and superclass . The rank of subdivision in plants and fungi is equivalent to subphylum.... 2
sectio	section2
	subsection2
	group
	subgroup Subgroup In group theory, given a group G under a binary operation *, we say that some subset H of G is a subgroup of G if H also forms a group under the operation *....
	superlegion
legio	legion Legion (biology) The legion, in Biology taxonomy, is a non-obligatory taxonomic rank within the Linnaean taxonomy which is subordinate to the Class but superordinate to the cohort ....
	sublegion
	infralegion
supercohors	supercohort
cohors	cohort
subcohors	subcohort
	magnorder Order (biology) In Biological classification used in biology, the order is a taxonomic rank between class and family . The superorder is a rank between class and order....
superordo	superorder Order (biology) In Biological classification used in biology, the order is a taxonomic rank between class and family . The superorder is a rank between class and order....
	series Series (botany) Series is a low-level taxonomic rank below that of section but above that of species.In botany, a series is a subdivision of a genus. It is typically used to help organize very large genus, which may have hundreds of species....
	subseries
	grandorder
	gigaorder
	megaorder
	mirorder
ordo	order Order (biology) In Biological classification used in biology, the order is a taxonomic rank between class and family . The superorder is a rank between class and order....
hyperordo	hyperorder
subordo	suborder Order (biology) In Biological classification used in biology, the order is a taxonomic rank between class and family . The superorder is a rank between class and order....
infraordo	infraorder Order (biology) In Biological classification used in biology, the order is a taxonomic rank between class and family . The superorder is a rank between class and order....
	parvorder Order (biology) In Biological classification used in biology, the order is a taxonomic rank between class and family . The superorder is a rank between class and order....
falanx
superfamilia	superfamily Family (biology) In biological classification, family is a taxonomic rank. Exact details of formal nomenclature depend on the Nomenclature Codes which applies....
	family group
familia	family Family (biology) In biological classification, family is a taxonomic rank. Exact details of formal nomenclature depend on the Nomenclature Codes which applies....
	subfamily group
subfamilia	subfamily Family (biology) In biological classification, family is a taxonomic rank. Exact details of formal nomenclature depend on the Nomenclature Codes which applies....
	infrafamily
supertribus	supertribe
tribus	tribe Tribe (biology) In biology, a tribe — or infrafamily — is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes....
subtribus	subtribe Tribe (biology) In biology, a tribe — or infrafamily — is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes....
	infratribe
supergenus	supergenus
	genus group
genus	genus Genus A genus is a low-level taxonomic rank used in the classification of living and fossil organisms. The taxonomic ranks are domain , kingdom , phylum, class , order , family , genus, and species....
subgenus	subgenus Subgenus In biology, a subgenus is a taxonomic rank directly below genus. See rank and rank .In ICZN, a subgeneric name can be used independently or included in a binomen, in parentheses, placed between the name of a biological genus and specific name: e.g....
	infragenus
supersectio	supersection1
sectio	section1
subsectio	subsection1
	infrasection1
	superseries1
series	series Series (botany) Series is a low-level taxonomic rank below that of section but above that of species.In botany, a series is a subdivision of a genus. It is typically used to help organize very large genus, which may have hundreds of species.... 1
	subseries1
	infraseries1
superspecies	superspecies Cryptic species complex In biology, a cryptic species complex is a group of species which satisfy the biological definition of species, that is, they are reproductively isolated from each other, but their morphology is very similar ....
	complex
	species group
	species subgroup
	aggregate
	synklepton
species	species Species In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring....
	microspecies
klepton	klepton
	aggregate
subspecies	subspecies Subspecies In biology, subspecies is the taxonomic rank immediately subordinate to a species. A subspecies is a taxonomic group which is less distinct than the Common descent or species from which it originates....
	infraspecies
	group
hybrid	hybrid
convarietas	convariety
supervarietas	supervariety
varietas	variety
subvarietas	subvariety Subvariety In botanical nomenclature, a subvariety is a taxonomic rank below that of Variety but above that of Form : it is an infraspecific taxon. Its name consists of three parts: a genus name, a specific epithet and an infraspecific epithet....
	infravariety
natio Natio Natio is*the Latin language term for a nation, meaning to be born .*It may also refer to a nation , a student organisation in ancient and medieval universities....
superforma	superform
forma, morpha	form Form (botany) In botanical nomenclature, a form is a low-level taxonomic rank below that of Variety ; it is an infraspecific taxon. Its name consists of three parts: a genus name, a specific epithet, and an infraspecific epithet....
subforma	subform
	infraform
	cultivar group Cultivar group Under the botanical nomenclature of the International Code of Nomenclature for Cultivated Plants , a cultivar group is any gathering of cultivars designated by common traits....
	cultivar Cultivar A cultivar is a cultivated plant that has been selected and given a unique name because of its decorative or useful characteristics; it is usually distinct from similar plants and when Plant propagation it retains those characteristics....
	group of breeds
	section of breeds
	breed Breed A breed is a group of Domestication with a Homogeneity appearance, behavior, and other characteristics that distinguish it from other animals of the same species.... , race RACE (biology) RACE, or Rapid Amplification of cDNA Ends, is a technique used in molecular biology to obtain the full length sequence of an RNA transcript found within a cell....
	strain Strain (biology) In biology, strain is a low-level taxonomic rank used in three related ways....
aberratio	aberration
	serogroup
	serotype Serotype For the term's use in bacteriology, see serovar.Transplants between genetically non-identical humans induce the creation of antibodies in the recipient.... , serovar Serovar A serovar or serotype is a group of microorganisms or viruses classified together based on their cell surface antigens. Serovars allow the epidemiologic classification of organisms to the sub-species level....
	biotype, biovar Biovar A biovar is a variant prokaryotic Strain that differs physiologically and/or biochemically from other strains in a particular species. Morphovars are those strains that differ physiologically....
	pathotype, pathovar Pathovar A pathovar is a bacterial strain or set of strains with the same or similar characteristics, that is differentiated at infrasubspecific level from other strains of the same species or subspecies on the basis of distinctive pathogenicity to one or more plant hosts....
	population Population File:Population density.pngIn biology, a population is the collection of inter-breeding organisms of a particular species; in sociology, a collection of human beings....
lusus	lusus Lusus Lusus is the supposed son or companion of Bacchus, the Roman mythology of wine and divine madness, to whom Portugal National myth attributed the foundation of ancient Lusitania and the fatherhood of the its inhabitants, the Lusitanians, seen as the ancestors of the modern Portuguese people....

Notes to table: ¹ Level in plant taxonomy. ² Level in animal taxonomy.


A summary of this scheme, from most general to most specific, would be:

• Domain
  Domain (biology)
  
  In Biology taxonomy, a domain is the highest taxonomic rank of organisms, higher than a Kingdom . According to the three-domain system of Carl Woese, introduced in 1990, the Tree of life consists of three domains: Archaea, Bacteria and Eukaryota....
   or Empire
• Superkingdom
• Kingdom
  Kingdom (biology)
  
  In Biology taxonomy, kingdom or regnum is a taxonomic rank in either the highest rank, or the Rank below domain . Each kingdom is divided into smaller groups called Phylum ....
  
• Subkingdom
• Branch
• Infrakingdom
• Superphylum (or Superdivision in botany)
• Phylum (or Division in botany)
• Subphylum
  Subphylum
  
  In life, a subphylum is a taxonomic rank intermediate between phylum and superclass . The rank of subdivision in plants and fungi is equivalent to subphylum....
   (or Subdivision in botany)
• Infraphylum (or Infradivision in botany)
• Microphylum
• Supercohort (botany)
• Cohort (botany)
• Subcohort (botany)
• Infracohort (botany)
• Superclass
  Superclass
  
  Superclass may be:* The global ruling class created by globalization .* Superclass , a book about global governance by David Rothkopf.* Superclass , a taxonomic rank intermediate between subphylum and class....
  
• Class
  Class (biology)
  
  A class is the taxonomic rank in the biological classification of organisms in biology below phylum and above Order .The orders of taxonomy are life, Domain , kingdom , phylum, class , order , family , genus, and species....
  
• Subclass
  Subclass
  
  Subclass may refer to:* Subclass , a taxonomic rank intermediate between class and superorder* Subclass , a class that is derived from another class or classes...
  
• Infraclass
• Parvclass
• Superdivision (zoology)
• Division (zoology)
• Subdivision (zoology)
• Infradivision (zoology)
• Superlegion (zoology)
• Legion
  Legion (biology)
  
  The legion, in Biology taxonomy, is a non-obligatory taxonomic rank within the Linnaean taxonomy which is subordinate to the Class but superordinate to the cohort ....
   (zoology)
• Sublegion (zoology)
• Infralegion (zoology)
• Supercohort (zoology)
• Cohort (zoology)
• Subcohort (zoology)
• Infracohort (zoology)
• Gigaorder (zoology)
• Magnorder or Megaorder (zoology)
• Grandorder or Capaxorder (zoology)
• Mirorder or Hyperorder (zoology)
• Superorder
• Series (for fishes)
• Order
  Order (biology)
  
  In Biological classification used in biology, the order is a taxonomic rank between class and family . The superorder is a rank between class and order....
  
• Parvorder (position in some zoological classifications)
• Nanorder (zoology)
• Hypoorder (zoology)
• Minorder (zoology)
• Suborder
• Infraorder
• Parvorder (usual position) or Microorder (zoology)
• Section (zoology)
• Subsection (zoology)
• Gigafamily (zoology)
• Megafamily (zoology)
• Grandfamily (zoology)
• Hyperfamily (zoology)
• Superfamily
• Epifamily (zoology)
• Series (for Lepidoptera)
• Group (for Lepidoptera)
• Family
  Family (biology)
  
  In biological classification, family is a taxonomic rank. Exact details of formal nomenclature depend on the Nomenclature Codes which applies....
  
• Subfamily
• Infrafamily
• Supertribe
• Tribe
  Tribe (biology)
  
  In biology, a tribe — or infrafamily — is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes....
  
• Subtribe
• Infratribe
• Genus
  Genus
  
  A genus is a low-level taxonomic rank used in the classification of living and fossil organisms. The taxonomic ranks are domain , kingdom , phylum, class , order , family , genus, and species....
  
• Subgenus
  Subgenus
  
  In biology, a subgenus is a taxonomic rank directly below genus. See rank and rank .In ICZN, a subgeneric name can be used independently or included in a binomen, in parentheses, placed between the name of a biological genus and specific name: e.g....
  
• Section (botany)
• Subsection (botany)
• Series (botany)
• Subseries (botany)
• Superspecies
  Cryptic species complex
  
  In biology, a cryptic species complex is a group of species which satisfy the biological definition of species, that is, they are reproductively isolated from each other, but their morphology is very similar ....
   or Species-group
• Species
  Species
  
  In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring....
  
• Subspecies
  Subspecies
  
  In biology, subspecies is the taxonomic rank immediately subordinate to a species. A subspecies is a taxonomic group which is less distinct than the Common descent or species from which it originates....
   (or Forma Specialis for fungi, or Variety for bacteria)
• Variety (botany) or Form/Morph (zoology)
• Subvariety
  Subvariety
  
  In botanical nomenclature, a subvariety is a taxonomic rank below that of Variety but above that of Form : it is an infraspecific taxon. Its name consists of three parts: a genus name, a specific epithet and an infraspecific epithet....
   (botany)
• Form
  Form (botany)
  
  In botanical nomenclature, a form is a low-level taxonomic rank below that of Variety ; it is an infraspecific taxon. Its name consists of three parts: a genus name, a specific epithet, and an infraspecific epithet....
   (botany)
• Subform (botany)

Of these many ranks, the only one that has an exact biological definition is species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring....
. The other levels are intended to represent the phylogeny

Phylogenetics

In biology, phylogenetics is the study of evolutionary relatedness among various groups of organisms , which is discovered through molecular sequencing data and morphological data matrices....
 of the organisms under discussion, and are to some extent a matter of judgement. For most groups of organisms, not all the ranks would actually be used; they have been defined to deal with the most complicated cases, such as insects and vertebrates.

Bibliography

• Benton, Michael J.
  Michael J. Benton
  
  Michael J. Benton is a Fellow of the Royal Society of Edinburgh and professor of vertebrate paleontology in the Department of Earth Sciences at the University of Bristol....
   2005. Vertebrate Palaeontology, 3rd ed. Oxford: Blackwell Publishing. ISBN 0-632-05637-1. ISBN-13: ISBN 978-0-632-05637-8
• Brummitt, R.K., and C.E. Powell. 1992. Authors of Plant Names. Royal Botanic Gardens, Kew. ISBN 0947643443
• Carroll, Robert L.
  Robert L. Carroll
  
  Robert Lynn Carroll is a vertebrate paleontologist who specialises in Paleozoic and Mesozoic amphibians and reptiles.Carroll was an only child and grew up on a farm near Lansing, Michigan....
   1988. Vertebrate Paleontology and Evolution. New York: W.H. Freeman & Co. ISBN 0-716-7-1822-7
• Gaffney, Eugene S., and Peter A. Meylan. 1988. "A phylogeny of turtles." In M.J. Benton (ed.), The Phylogeny and Classification of the Tetrapods, Volume 1: Amphibians, Reptiles, Birds, 157–219. Oxford: Clarendon Press.
• International Association for Plant Taxonomy. 2000. International Code of Botanical Nomenclature (Saint Louis Code), Electronic version. Retrieved on 2007-07-21.
• Haris Abba Kabara. Karmos hand book for botanical names.
• Lambert, David. 1990. Dinosaur Data Book. Oxford: Facts On File & British Museum (Natural History). ISBN 0-8160-2431-6
• McKenna, Malcolm C., and Susan K. Bell (editors). 1997. Classification of Mammals Above the Species Level. New York: Columbia University Press. ISBN 0-231-11013-8
• Milner, Andrew. 1988. "The relationships and origin of living amphibians." In M.J. Benton (ed.), The Phylogeny and Classification of the Tetrapods, Volume 1: Amphibians, Reptiles, Birds, 59–102. Oxford: Clarendon Press.
• Novacek, Michael J. 1986. "The skull of leptictid insectivorans and the higher-level classification of eutherian mammals." Bulletin of the American Museum of Natural History 183: 1–112.
• Sereno, Paul C. 1986. "Phylogeny of the bird-hipped dinosaurs (Order Ornithischia)." National Geographic Research 2: 234–56.
• Willis, K.J., and J.C. McElwain. 2002. The Evolution of Plants. Oxford University Press. ISBN 0-19-850065-3

See also

• Cladistics
  Cladistics
  
  Cladistics is the hierarchical classification of species based on evolutionary ancestry. Cladistics is distinguished from other taxonomic systems because it focuses on evolution rather than similarities between species, and because it places heavy emphasis on objective, quantitative analysis....
  
• ICZN
  ICZN
  
  ICZN may refer to:*International Commission on Zoological Nomenclature, an organization*International Code of Zoological Nomenclature, published by that organization...