{{Otheruses}}{{pp-semi-protected|small=yes}}{{Otheruses}}{{pp-semi-protected|small=yes}}
{{Taxobox
| name = Hadrosaurids
| image = Parasaurolophus cyrtocristatus.jpg
| image_width = 250px
| image_caption =
Parasaurolophus cyrtocristatusParasaurolophus is a genus of ornithopod dinosaur from the Late Cretaceous Period of what is now North America, about 76-73 million years ago. It was a herbivore that walked both as a biped and a quadruped. Three species are recognized: P. walkeri , P...
at
Field Museum of Natural HistoryThe Field Museum of Natural History is located in Chicago, Illinois, USA. It sits on Lake Shore Drive next to Lake Michigan, part of a scenic complex known as the Museum Campus Chicago...
| fossil_range =
Late CretaceousThe Late Cretaceous is the youngest of two epochs in which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
, {{fossilrange|100|65}}
| regnum =
AnimalAnimals are a major group of mostly multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously...
ia
| phylum =
ChordataChordates are animals which are either vertebrates or one of several closely related invertebrates. They are united by having, for at least some period of their life cycle, a notochord, a hollow dorsal nerve cord, pharyngeal slits, an endostyle, and a post-anal tail...
| classis =
ReptiliaReptiles, or members of the class Reptilia, are air-breathing, generally "cold-blooded" amniotes that generally have skin covered in scales or scutes. They are tetrapods and lay amniote eggs, whose embryos are surrounded by the amnion membrane...
| superordo =
Dinosaur{{Otheruses}}{{pp-semi-protected|small=yes}}{{Otheruses}}{{pp-semi-protected|small=yes}}{{Taxobox|name = Dinosaurs|fossil_range = {{Fossil range|230|65|earliest=230|latest=0|PS=
Descendant taxon Aves survives to present.}}|image = field_dinos_2.jpg...
ia
| ordo =
OrnithischiaOrnithischia or Predentata is an extinct order of beaked, herbivorous dinosaurs. The name ornithischia is derived from the Greek ornitheos meaning 'of a bird' and ischion meaning 'hip joint'...
| subordo =
CerapodaCerapoda is a clade or suborder of the order Ornithischia. They are the sister group of the Thyreophora within the clade Genasauria. Cerapods are united by having a thicker layer of enamel on the inside of their lower teeth...
| infraordo = Ornithopoda
| superfamilia =
HadrosauroideaHadrosauroidea is a clade or superfamily of ornithischian dinosaurs that includes the "duck-billed" dinosaurs, or hadrosaurids, and their close relatives. Many primitive hadrosauroids, such as the sail-backed Ouranosaurus, have traditionally been included in a paraphyletic "Iguanodontidae"...
| familia =
Hadrosauridae
| familia_authority =
CopeEdward Drinker Cope was an American paleontologist and comparative anatomist, as well as a noted herpetologist and ichthyologist. Born to a wealthy Quaker family, Cope quickly distinguished himself as a child prodigy interested in science; he published his first scientific paper at the age of...
, 1869
| subdivision_ranks =
SubfamiliesIn biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus...
| subdivision =
- Hadrosaurinae Cope, 1869
- Lambeosaurinae Parks
William Arthur Parks was a Canadian geologist and paleontologist, following in the tradition of Lawrence Lambe....
, 1923
| synonyms =
- Trachodontidae Lydekker
Richard Lydekker was an English naturalist, geologist and writer of numerous books on natural history.Lydekker was born in London, and educated at Trinity College, Cambridge, where he took a first-class in the Natural Science tripos...
, 1888
- Saurolophidae Brown
Barnum Brown , born in Carbondale, Kansas, and named after the circus showman P.T. Barnum, was perhaps the most famous fossil hunter of the early twentieth century....
, 1914
- Lambeosauridae Parks, 1923 vide Horner, 1990
}}
Hadrosaurids or
duck-billed dinosaur{{Otheruses}}{{pp-semi-protected|small=yes}}{{Otheruses}}{{pp-semi-protected|small=yes}}{{Taxobox|name = Dinosaurs|fossil_range = {{Fossil range|230|65|earliest=230|latest=0|PS=
Descendant taxon Aves survives to present.}}|image = field_dinos_2.jpg...
s are members of the family
Hadrosauridae, and include
ornithopodOrnithopods are a group of bird-hipped dinosaurs that started out as small, bipedal running grazers, and grew in size and numbers until they became one of the most successful groups of herbivores in the Cretaceous world, and dominated the North American landscape...
s such as
EdmontosaurusEdmontosaurus is a genus of crestless duck-billed dinosaur. The fossils of this animal have been found in rocks of western North America that date from the late Campanian stage to the end of the Maastrichtian stage of the Cretaceous Period, between 73 and 65.5 million years ago...
and
ParasaurolophusParasaurolophus is a genus of ornithopod dinosaur from the Late Cretaceous Period of what is now North America, about 76-73 million years ago. It was a herbivore that walked both as a biped and a quadruped. Three species are recognized: P. walkeri , P...
. They were common
herbivoreA herbivore is an animal that is adapted to eat plants and not meat.Herbivory is a form of predation in which an organism consumes principally autotrophs such as plants, algae and photosynthesizing bacteria....
s in the Upper
CretaceousThe Cretaceous , Latin language for "chalky", 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 on the Jurassic period and is followed by the Paleogene period of the...
Period of what are now
AsiaAsia is the world's largest and most populous continent, located in the eastern and northern hemispheres. It covers 8.6% of the earth's total surface area and with approximately 4 billion people, it hosts 60% of the world's current human population.Asia is traditionally defined as part of the...
,
EuropeEurope is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally divided from Asia to its east by the water divide of the Ural Mountains, the Ural River, the Caspian Sea, the Caucasus Mountains , and the Black Sea to the southeast...
and
North AmericaNorth America is the northern continent of the Americas, situated in the Earth's northern hemisphere and in the western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the west by the North Pacific...
. They are descendants of the Upper
JurassicThe Jurassic is a geologic period and system that extends from about Ma to Ma, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the "Age of Reptiles". The start of the period is marked by...
/Lower Cretaceous iguanodontian dinosaurs and had similar body layout. They were
ornithischiaOrnithischia or Predentata is an extinct order of beaked, herbivorous dinosaurs. The name ornithischia is derived from the Greek ornitheos meaning 'of a bird' and ischion meaning 'hip joint'...
ns.
Hadrosaurids are divided into two subfamilies. The lambeosaurines (
Lambeosaurinae) had hollow cranial crests or tubes, and were generally less bulky. The hadrosaurines (
Hadrosaurinae) lacked hollow cranial crests (solid crests were present in some forms) and were generally larger.
Characteristics
The hadrosaurs are known as the duck-billed dinosaurs due to the similarity of their head to that of modern
duckDuck is the common name for a number of species in the Anatidae family of birds. The ducks are divided between several subfamilies listed in full in the Anatidae article; they do not represent a monophyletic group but a form taxon, since swans and geese are not considered ducks...
s. In some genera, most notably
AnatotitanAnatotitan is a genus of flat-headed or hadrosaurine hadrosaurid ornithopod dinosaur from the very end of the Cretaceous Period, in what is now North America...
, the whole front of the skull was flat and broadened out to form a beak, ideal for clipping leaves and twigs from the
forestA forest is an area with a high density of trees. There are many definitions of a forest, based on the various criteria. These plant communities presently cover approximately 9.4% of the Earth's surface in many different regions and function as habitats for organisms, hydrologic flow modulators,...
s of Asia, Europe and North America. However, the back of the mouth contained literally thousands of teeth suitable for grinding food before it was swallowed. This has been hypothesized to have been a crucial factor in the success of this group in the Cretaceous, compared to the sauropods which were still largely dependent on
gastrolithA gastrolith, also called a stomach stone or gizzard stones, is a rock held inside a gastrointestinal tract. Gastroliths are retained in the muscular gizzard and used to grind food in animals lacking suitable grinding teeth. The grain size depends upon the size of the animal and the gastrolith's...
s for grinding their food.
In 2009, paleontologist
Mark PurnellDr Mark Andrew Purnell is a British palaeontologist, Reader of Geology at the University of Leicester.Purnell is an expert in conodont biostratigraphy and conodont palaeobiology, focussing especially on attempts to uncover the function of conodont elements...
conducted a study into the chewing methods and diet of
hadrosauridsHadrosaurids or duck-billed dinosaurs are members of the family Hadrosauridae, and include ornithopods such as Edmontosaurus and Parasaurolophus. They were common herbivores in the Upper Cretaceous Period of what are now Asia, Europe and North America. They are descendants of the Upper...
, a
herbivoreA herbivore is an animal that is adapted to eat plants and not meat.Herbivory is a form of predation in which an organism consumes principally autotrophs such as plants, algae and photosynthesizing bacteria....
species of duck-billed
dinosaurs{{Otheruses}}{{pp-semi-protected|small=yes}}{{Otheruses}}{{pp-semi-protected|small=yes}}{{Taxobox|name = Dinosaurs|fossil_range = {{Fossil range|230|65|earliest=230|latest=0|PS=
Descendant taxon Aves survives to present.}}|image = field_dinos_2.jpg...
from the
Late Cretaceous periodThe Late Cretaceous is the youngest of two epochs in which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
. By analyzing hundreds of microscopic scratches on the teeth of a fossilized
EdmontosaurusEdmontosaurus is a genus of crestless duck-billed dinosaur. The fossils of this animal have been found in rocks of western North America that date from the late Campanian stage to the end of the Maastrichtian stage of the Cretaceous Period, between 73 and 65.5 million years ago...
jaw, the team determined hadrosaurs had a unique way of eating unlike any creature living today. In contrast to a flexible lower jaw joint prevalent in today's mammals, hadrosaurs had a unique hinge between the upper jaws and the rest of its skull. The team found the dinosaur's upper jaws pushed outwards and sideways while chewing, as the lower jaw slid against the upper teeth.
Discoveries
Hadrosaurids were the first dinosaur family to be identified in North America, the first traces being found in 1855-1856 with the discovery of
fossilFossils are the preserved remains or traces of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous rock formations and sedimentary layers is known as the fossil record...
teeth.
Joseph LeidyJoseph Leidy was an American paleontologist.Leidy was professor of anatomy at the University of Pennsylvania, and later was a professor of natural history at Swarthmore College. His book Extinct Fauna of Dakota and Nebraska contained many species not previously described and many previously...
examined the teeth, and erected the
generaIn biology, a genus is a taxonomic unit used in the classification of living and fossil organisms. The term comes from Latin genus "descent, family, type, gender" , cognate with – genos, "race, stock, kin" ..In addition, genus is a taxonomic rank in the hierarchy In biology, a genus (plural:...
TrachodonTrachodon is a dubious genus of hadrosaurid dinosaur based on teeth from the Campanian-age Upper Cretaceous Judith River Formation of Montana, U.S.A...
and
ThespesiusThespesius is a dubious genus of hadrosaurid dinosaur based on two caudal vertebrae and a phalanx from the late Maastrichtian-age Upper Cretaceous Lance Formation of South Dakota...
(others included
TroodonTroodon is a genus of relatively small, bird-like dinosaur from the Late Cretaceous period . Discovered in 1855, it was among the first dinosaurs found in North America....
,
DeinodonDeinodon is a name assigned to tyrannosaurid teeth of the Late Cretaceous of Montana by paleontologist Joseph Leidy in 1856...
and
PalaeoscincusPalaeoscincus is a dubious genus of ankylosaurian dinosaur based on teeth from the mid-late Campanian-age Upper Cretaceous Judith River Formation of Montana...
). One species was named
Trachodon mirabilis. Now it seems that the teeth genus
Trachodon is a mixture of all sorts of cerapod dinosaurs, including ceratopsids. In 1858 the teeth were associated with Leidy's eponymous
HadrosaurusHadrosaurus is a dubious genus of hadrosaurid dinosaur. In 1858, a skeleton of a dinosaur from this genus was the first dinosaur skeleton known from more than isolated teeth to be found in North America. In 1868, it became the first ever mounted dinosaur skeleton...
foulkii, named after the fossil hobbyist
William Parker FoulkeWilliam Parker Foulke discovered the first full dinosaur skeleton in North America in Haddonfield, New Jersey in 1858....
. More and more teeth were found, resulting in even more (now obsolete) genera.
A second duck-bill skeleton was unearthed, and was named
Diclonius mirabilis in 1883 by
Edward Drinker CopeEdward Drinker Cope was an American paleontologist and comparative anatomist, as well as a noted herpetologist and ichthyologist. Born to a wealthy Quaker family, Cope quickly distinguished himself as a child prodigy interested in science; he published his first scientific paper at the age of...
, which he incorrectly used in favor of
Trachodon mirabilis. But
Trachodon, together with other poorly typed genera, was used more widely and, when Cope's famous "
Diclonius mirabilis" skeleton was mounted at the
American Museum of Natural HistoryThe American Museum of Natural History , located on the Upper West Side, Manhattan, New York, USA, is one of the largest and most celebrated museums in the world...
, it was labeled as "Trachodont dinosaur". The duck-billed dinosaur family was then named Trachodontidae.
A very well-preserved complete hadrosaurid specimen (
Edmontosaurus annectens) was recovered in 1908 by the fossil collector
Charles Hazelius SternbergCharles Hazelius Sternberg , was an American fossil collector and amateur paleontologist. His older brother, Dr. George M. Sternberg was a military surgeon assigned to Fort Harker near Ellsworth, Kansas and brought the rest of Sternberg family to Kansas to live on his ranch about 1868...
and his three sons, in
Converse County, WyomingConverse County is a county located in the U.S. state of Wyoming. As of 2000, the population was 12,052. Its county seat is Douglas.-Geography:According to the U.S...
. Analyzed by
Henry OsbornHenry Fairfield Osborn was an American geologist, paleontologist, and eugenicist, "a first-rate science administrator and a third-rate scientist."...
in 1912, it has come to be known as the "
Trachodon mummyThe Trachodon mummy is a very well-preserved fossil of Edmontosaurus annectens, a duckbilled dinosaur. It was found by Charles Hazelius Sternberg and his three sons near Lusk, Wyoming, USA in 1908...
". This specimen's skin was almost completely preserved in the form of impressions.
Lawrence LambeLawrence Morris Lambe was a Canadian geologist and palaeontologist from the Geological Survey of Canada . His published work, describing the diverse and plentiful dinosaur discoveries from the fossil beds in Alberta, did much to bring dinosaurs into the public eye and helped usher in the Golden...
erected the genus
Edmontosaurus ("lizard from Edmonton") in 1917 from a find in the lower Edmonton Formation (now
Horseshoe Canyon FormationThe Horseshoe Canyon Formation is part of the Edmonton Group and is up to 230m in thickness. It is Late Campanian to Early Maastrichtian in age and is composed of mudstone, sandstone, and carbonaceous shales...
),
AlbertaAlberta is one of Canada's prairie provinces. It became a province on September 1, 1905.Alberta is located in western Canada, bounded by the provinces of British Columbia to the west and Saskatchewan to the east, the Northwest Territories to the north, and the U.S. state of Montana to the south....
. Hadrosaurid systematics were addressed in a 1942
monographA monograph is a work of writing upon a single subject, usually also by a single author. It is often a scholarly essay or learned treatise, and may be released in the manner of a book or journal article. It is by definition a single document that forms a complete text in itself...
by Richard Swann Lull and Nelda Wright. They proposed the genus
Anatosaurus for several species of dubious genera. Cope's famous mount at the AMNH became
Anatosaurus copei. In 1990,
Anatosaurus was moved to
Edmontosaurus. One former
Anatosaurus species was distinct enough from
Edmontosaurus to be placed in a separate genus, named
AnatotitanAnatotitan is a genus of flat-headed or hadrosaurine hadrosaurid ornithopod dinosaur from the very end of the Cretaceous Period, in what is now North America...
, so in 1990 the AMNH mount was re-labelled
Anatotitan copei.
Paleontologists have found a hadrosaurid leg bone in
PaleoceneThe Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from 65.5 ± 0.3 Ma to 55.8 ± 0.2 Ma . It is the first epoch of the Palaeogene Period in the modern Cenozoic era...
rocks, but it was probably reworked from a
CretaceousThe Cretaceous , Latin language for "chalky", 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 on the Jurassic period and is followed by the Paleogene period of the...
source.
One of the most complete fossilized specimens was found in 1999 in
Hell Creek FormationThe Hell Creek Formation is an intensely-studied division of Upper Cretaceous to lower Paleocene rocks in North America, named for exposures studied along Hell Creek, near Jordan, Montana....
of North Dakota and now is nicknamed "
DakotaDakota is the nickname given to a fossil Edmontosaurus from the Hell Creek Formation in North Dakota. It is about 67 million years old, placing it in the Maastrichtian, the last stage of the Cretaceous period...
". The hadrosaur fossil is so well preserved that scientists have been able to calculate its muscle mass and learn that it was more muscular than thought, probably giving it the ability to outrun predators such as
Tyrannosaurus rex. Unlike the collections of bones found in museums, this mummified hadrosaur fossil comes complete with skin (not merely skin impressions), ligaments, tendons and possibly some internal organs. It is being analyzed in the world's largest CT scanner, operated by the
Boeing CoThe Boeing Company is a major aerospace and defense corporation, founded by William E. Boeing in Seattle, Washington. Boeing has expanded over the years, merging with McDonnell Douglas in 1997. Its international headquarters has been in Chicago, Illinois, since 2001...
. The machine usually is used for detecting flaws in space shuttle engines and other large objects, but previously none as large as this. Researchers hope the technology will help them learn more about the fossilized insides of the creature. They also found a gap of about a centimeter between each vertebra, indicating there may have been a disk or other material between them, allowing more flexibility and meaning the animal was actually longer than what is shown in a museum.
Taxonomy
The family Hadrosauridae was first used by
Edward Drinker CopeEdward Drinker Cope was an American paleontologist and comparative anatomist, as well as a noted herpetologist and ichthyologist. Born to a wealthy Quaker family, Cope quickly distinguished himself as a child prodigy interested in science; he published his first scientific paper at the age of...
in 1869. Since its creation, a major division has been recognized in the group, between the (generally crested) subfamily Lambeosaurinae and (generally crestless) subfamily Hadrosaurinae. Phylogenetic analysis has increased the resolution of hadrosaurid relationships considerably (see Phylogeny below), leading to the widespread usage of tribes (a taxonomic unit below subfamily) to describe the finer relationships within each group of hadrosaurids. However, many hadrosaurid tribes commonly recognized in online sources have not yet been formally defined or seen wide use in the literature. Several were briefly mentioned but not named as such in the first edition of
The Dinosauria, under informal names. In this 1990 reference, "gryposaurs" included
AralosaurusAralosaurus meaning "Aral Sea lizard", because it was found in the Aral Sea was a genus of hadrosaurid dinosaur which lived during the Late Cretaceous of what is now Kazakhstan...
,
GryposaurusGryposaurus was a genus of duckbilled dinosaur that lived about 83 to 75 million years ago, in the Late Cretaceous of North America...
,
HadrosaurusHadrosaurus is a dubious genus of hadrosaurid dinosaur. In 1858, a skeleton of a dinosaur from this genus was the first dinosaur skeleton known from more than isolated teeth to be found in North America. In 1868, it became the first ever mounted dinosaur skeleton...
, and
KritosaurusKritosaurus is an incompletely known but historically important genus of hadrosaurid dinosaur...
; "brachylophosaurs" included
BrachylophosaurusBrachylophosaurus Brachylophosaurus Brachylophosaurus ( or ; meaning "short-crested lizard" (Greek brachy = short + lophos = crest + sauros = lizard, referring to its small crest) was a mid-sized member of the hadrosaurid family of dinosaurs...
and
MaiasauraMaiasaura is a large duck-billed dinosaur genus that lived in the area currently covered by the state of Montana in the Upper Cretaceous Period , about 74 million years ago.-Description:...
; "saurolophs" included
LophorhothonLophorhothon is the first genus of dinosaur discovered in Alabama. Remains of this small, poorly-known hadrosaurine euhadrosaurid dinosaur were first discovered during the 1940s, from extensive erosional outcrops of the lower unnamed member of the Mooreville Chalk Formation in Dallas County, west...
,
ProsaurolophusProsaurolophus is a genus of hadrosaurid dinosaur from the Late Cretaceous of North America. It is known from the remains of at least 25 individuals belonging to two species, including skulls and skeletons, but it remains obscure...
, and
SaurolophusSaurolophus is a genus of large hadrosaurine duckbill that lived about 70 million years ago, in the Late Cretaceous of North America and Asia ; it is one of the few genera of dinosaurs known from multiple continents. It is distinguished by a spike-like crest which projects up and back from...
; and "edmontosaurs" included
AnatotitanAnatotitan is a genus of flat-headed or hadrosaurine hadrosaurid ornithopod dinosaur from the very end of the Cretaceous Period, in what is now North America...
,
EdmontosaurusEdmontosaurus is a genus of crestless duck-billed dinosaur. The fossils of this animal have been found in rocks of western North America that date from the late Campanian stage to the end of the Maastrichtian stage of the Cretaceous Period, between 73 and 65.5 million years ago...
, and
ShantungosaurusShantungosaurus, meaning "Shandong Lizard", is a genus of flat headed hadrosaurid dinosaurs found in the Late Cretaceous Wangshi Formation of the Shandong Peninsula in China....
.
Lambeosaurines have also been split into Parasaurolophini (
ParasaurolophusParasaurolophus is a genus of ornithopod dinosaur from the Late Cretaceous Period of what is now North America, about 76-73 million years ago. It was a herbivore that walked both as a biped and a quadruped. Three species are recognized: P. walkeri , P...
) and Corythosaurini (
CorythosaurusCorythosaurus Corythosaurus Corythosaurus was a genus of duck-billed dinosaur from the Upper Cretaceous Period, about 75 million years ago...
,
HypacrosaurusHypacrosaurus was a genus of duckbill dinosaur similar in appearance to Corythosaurus. Like Corythosaurus, it had a tall, hollow rounded crest, although not as large and straight...
, and
LambeosaurusLambeosaurus is a genus of hadrosaurid dinosaur that lived about 76 to 75 million years ago, in the Late Cretaceous Period of North America. This bipedal/quadrupedal, herbivorous dinosaur is known for its distinctive hollow cranial crest, which in the best-known species resembled a hatchet...
). Corythosaurini and Parasaurolophini as terms entered the formal literature in Evans and Reisz's 2007 redescription of
Lambeosaurus magnicristatus. Corythosaurini is defined as all
taxa|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement. Defining what belongs or does not belong to such a...
more closely related
Corythosaurus casuarius than to
Parasaurolophus walkeri, and Parasaurolophini as all those taxa closer to
P. walkeri than to
C. casuarius. In this study,
CharonosaurusCharonosaurus is the name of a genus of dinosaur whose fossils were discovered by Godefroit, Zan & Jin in 2000 on the south bank of the Amur River, dividing China from Russia.-Description:...
and
Parasaurolophus are parasaurolophins, and
Corythosaurus,
Hypacrosaurus,
Lambeosaurus,
NipponosaurusNipponosaurus is a lambeosaurine hadrosaurid from Asia. The holotype was discovered in November 1934 during the construction of a hospital on Karafuto Prefecture , and additional material belonging to the specimen was recovered in the summer of 1937...
, and
OlorotitanOlorotitan was a genus of lambeosaurine duckbilled dinosaur from the middle or late Maastrichtian-age Late Cretaceous Tsagayan Formation beds located in Kundur, Amur Region, Far Eastern Russia. The remains, consisting of a nearly complete skeleton, were described by Pascal Godefroit et al. in...
are corythosaurins. The enigmatic genus
TsintaosaurusTsintaosaurus is a genus of hadrosaurid dinosaur from China. It was about long, tall and weighed 3 tons. The type species is T. spinorhinus, first described by C. C. Young in 1958....
may form a
cladeA clade is a term used in modern alpha taxonomy, the scientific classification of living and fossil organisms, to describe a monophyletic group, defined as a group consisting of a single common ancestor and all its descendants.[The term "monophyletic group" is used in this article...]
in Lambeosaurine with
PararhabdodonPararhabdodon was a genus of derived hadrosauroid or basal hadrosaurid dinosaur, from the Maastrichtian-age Upper Cretaceous Tremp Formation of Spain...
and its probable synonym
KoutalisaurusKoutalisaurus was a genus of hadrosaurid dinosaur. It is based on a mostly complete dentary from the Maastrichtian-age Upper Cretaceous Tremp Formation near the town of Abella de la Conca, Lleida, Spain...
.
The following
taxonomyLinnaean taxonomy is either# the particular classification of Linnaeus, as set forth in his Systema Naturae and subsequent works...
includes dinosaurs currently referred to the Hadrosauridae and its subfamilies. Hadrosaurids that were accepted as valid but were not placed in a cladogram at the time of the 2004 review in
The Dinosauria, or, in the case of lambeosaurines, the 2007 redescription of
Lambeosaurus magnicristatusLambeosaurus is a genus of hadrosaurid dinosaur that lived about 76 to 75 million years ago, in the Late Cretaceous Period of North America. This bipedal/quadrupedal, herbivorous dinosaur is known for its distinctive hollow cranial crest, which in the best-known species resembled a hatchet...
, are included at the highest level to which they were placed (either then, or in their description if they postdate the papers used here).
- Family Hadrosauridae
- Telmatosaurus
Telmatosaurus was a genus of basal hadrosaurid dinosaur from the Late Cretaceous. It was a relatively small hadrosaur, approximately 5 meters long, found in what is now Romania. The type species, Telmatosaurus transylvanicus, was described by Franz Nopcsa von Felső-Szilvás, in...
- Subfamily Hadrosaurinae
- Brachylophosaurus
Brachylophosaurus Brachylophosaurus Brachylophosaurus ( or ; meaning "short-crested lizard" (Greek brachy = short + lophos = crest + sauros = lizard, referring to its small crest) was a mid-sized member of the hadrosaurid family of dinosaurs...
- Edmontosaurus
Edmontosaurus is a genus of crestless duck-billed dinosaur. The fossils of this animal have been found in rocks of western North America that date from the late Campanian stage to the end of the Maastrichtian stage of the Cretaceous Period, between 73 and 65.5 million years ago...
(including AnatotitanAnatotitan is a genus of flat-headed or hadrosaurine hadrosaurid ornithopod dinosaur from the very end of the Cretaceous Period, in what is now North America...
in Horner et al., 2004)
- Gryposaurus
Gryposaurus was a genus of duckbilled dinosaur that lived about 83 to 75 million years ago, in the Late Cretaceous of North America...
- "Kritosaurus" australis
Kritosaurus is an incompletely known but historically important genus of hadrosaurid dinosaur...
- Lophorhothon
Lophorhothon is the first genus of dinosaur discovered in Alabama. Remains of this small, poorly-known hadrosaurine euhadrosaurid dinosaur were first discovered during the 1940s, from extensive erosional outcrops of the lower unnamed member of the Mooreville Chalk Formation in Dallas County, west...
- Maiasaura
Maiasaura is a large duck-billed dinosaur genus that lived in the area currently covered by the state of Montana in the Upper Cretaceous Period , about 74 million years ago.-Description:...
- Naashoibitosaurus
Naashoibitosaurus is a genus of hadrosaurid dinosaur that lived about 73 million years ago, in the Late Cretaceous, and was found in the Kirtland Formation of the San Juan Basin in New Mexico, United States. Only a partial skeleton has been found to date...
- Prosaurolophus
Prosaurolophus is a genus of hadrosaurid dinosaur from the Late Cretaceous of North America. It is known from the remains of at least 25 individuals belonging to two species, including skulls and skeletons, but it remains obscure...
- Saurolophus
Saurolophus is a genus of large hadrosaurine duckbill that lived about 70 million years ago, in the Late Cretaceous of North America and Asia ; it is one of the few genera of dinosaurs known from multiple continents. It is distinguished by a spike-like crest which projects up and back from...
- Wulagasaurus
Wulagasaurus is a genus of hadrosaurine hadrosaurid dinosaur from the Late Cretaceous of Heilongjiang, China. Its remains were found in a bonebed in the Maastrichtian-age Yuliangze Formation...
- Hadrosaurinae incertae sedis
- Anasazisaurus
Anasazisaurus is a genus of hadrosaurid ornithopod dinosaur that lived about 74 million years ago, in the Late Cretaceous Period. It was found in the Farmington Member of the Kirtland Formation, in the San Juan Basin of New Mexico, United States. Only a partial skull has been found to date...
- Hadrosaurus
Hadrosaurus is a dubious genus of hadrosaurid dinosaur. In 1858, a skeleton of a dinosaur from this genus was the first dinosaur skeleton known from more than isolated teeth to be found in North America. In 1868, it became the first ever mounted dinosaur skeleton...
- Kerberosaurus
Kerberosaurus was a genus of hadrosaurine duckbill dinosaur from the Maastrichtian-age Upper Cretaceous Tsagayan Formation of Blagoveschensk, Amur Region, Russia. It is based on bonebed material including skull remains indicating that it was related to Saurolophus and Prosaurolophus...
- Kritosaurus
Kritosaurus is an incompletely known but historically important genus of hadrosaurid dinosaur...
- Shantungosaurus
Shantungosaurus, meaning "Shandong Lizard", is a genus of flat headed hadrosaurid dinosaurs found in the Late Cretaceous Wangshi Formation of the Shandong Peninsula in China....
- Subfamily Lambeosaurinae
- Amurosaurus
Amurosaurus is a genus of lambeosaurine hadrosaurid dinosaur found in the Late Cretaceous of eastern Asia. Like most lambeosaurs, it would have been a primarily bipedal herbivore with a "duckbill" shaped snout and a hollow crest on top of its head, although such a crest has not been found...
- Angulomastacator
Angulomastacator is a genus of duck-billed dinosaur from the Campanian-age Aguja Formation of Big Bend National Park, Texas...
- Aralosaurus
Aralosaurus meaning "Aral Sea lizard", because it was found in the Aral Sea was a genus of hadrosaurid dinosaur which lived during the Late Cretaceous of what is now Kazakhstan...
- Arenysaurus
Arenysaurus is a genus of hadrosaurid dinosaur from the Late Cretaceous. It is known from a partial skull and skeleton found in late Maastrichtian-age rocks of the Pyrenees Mountains in Spain. The type species is A. ardevoli, described in 2009 by Pereda-Suberbiola et al., a group of researchers...
- Charonosaurus
Charonosaurus is the name of a genus of dinosaur whose fossils were discovered by Godefroit, Zan & Jin in 2000 on the south bank of the Amur River, dividing China from Russia.-Description:...
- Corythosaurus
Corythosaurus Corythosaurus Corythosaurus was a genus of duck-billed dinosaur from the Upper Cretaceous Period, about 75 million years ago...
- Hypacrosaurus
Hypacrosaurus was a genus of duckbill dinosaur similar in appearance to Corythosaurus. Like Corythosaurus, it had a tall, hollow rounded crest, although not as large and straight...
- Jaxartosaurus
Jaxartosaurus is a genus of hadrosaurid dinosaur similar to Corythosaurus which lived during the Late Cretaceous. Its fossils were found in Kazakhstan and China. It had a large, helmet-like crest that it may have used for visual identification, or to vocalize with members of the same herd.The type...
- Lambeosaurus
Lambeosaurus is a genus of hadrosaurid dinosaur that lived about 76 to 75 million years ago, in the Late Cretaceous Period of North America. This bipedal/quadrupedal, herbivorous dinosaur is known for its distinctive hollow cranial crest, which in the best-known species resembled a hatchet...
- Nipponosaurus
Nipponosaurus is a lambeosaurine hadrosaurid from Asia. The holotype was discovered in November 1934 during the construction of a hospital on Karafuto Prefecture , and additional material belonging to the specimen was recovered in the summer of 1937...
- Olorotitan
Olorotitan was a genus of lambeosaurine duckbilled dinosaur from the middle or late Maastrichtian-age Late Cretaceous Tsagayan Formation beds located in Kundur, Amur Region, Far Eastern Russia. The remains, consisting of a nearly complete skeleton, were described by Pascal Godefroit et al. in...
- Parasaurolophus
Parasaurolophus is a genus of ornithopod dinosaur from the Late Cretaceous Period of what is now North America, about 76-73 million years ago. It was a herbivore that walked both as a biped and a quadruped. Three species are recognized: P. walkeri , P...
- Sahaliyania
Sahaliyania is a genus of lambeosaurine hadrosaurid dinosaur from the Late Cretaceous of Heilongjiang, China...
- Tsintaosaurus
Tsintaosaurus is a genus of hadrosaurid dinosaur from China. It was about long, tall and weighed 3 tons. The type species is T. spinorhinus, first described by C. C. Young in 1958....
- Velafrons
Velafrons is a genus of lambeosaurine hadrosaurid dinosaur from the Late Cretaceous of Mexico. It is known from a mostly complete skull and partial skeleton of a juvenile individual, with a bony crest on the forehead...
- Lambeosaurinae incertae sedis
- Barsboldia
Barsboldia was a genus of large hadrosaurid dinosaur from the early Maastrichtian Nemegt Formation of Ömnogöv', Mongolia. It is known from a partial vertebral column, partial pelvis, and some ribs...
- Nanningosaurus
Nanningosaurus is a genus of hadrosaurid dinosaur from the late Cretaceous of the Nalong Basin, Guangxi, China. It is based on an incomplete skeleton including skull, arm, and hip remains. Some of its diagnostic characteristics include relatively few tooth positions, a gracile upper arm, and an...
- Hadrosaurids of uncertain placement (incertae sedis)
- Bactrosaurus
Bactrosaurus meaning "Bactrian lizard," "Bactria" + sauros = lizard)) was a herbivorous dinosaur that lived in east Asia during the late Cretaceous, 97 - 85 mya...
- Claosaurus
Claosaurus, Claosaurus, Claosaurus, ( , meaning 'broken lizard', referring to the odd position of the fossils when discovered (Greek klao meaning 'broken' and sauros meaning 'lizard') is a genus of primitive hadrosaurid (duck-billed dinosaur) that lived during the Late Cretaceous Period...
- Gilmoreosaurus
Gilmoreosaurus is the name given to a genus of dinosaur from the Early Cretaceous. The type species is Gilmoreosaurus mongoliensis. Gilmoreosaurus kysylumensis is considered a nomen dubium because it is described from teeth only, though other species preserve more material. It is believed, however,...
- Koutalisaurus
Koutalisaurus was a genus of hadrosaurid dinosaur. It is based on a mostly complete dentary from the Maastrichtian-age Upper Cretaceous Tremp Formation near the town of Abella de la Conca, Lleida, Spain...
- Pararhabdodon
Pararhabdodon was a genus of derived hadrosauroid or basal hadrosaurid dinosaur, from the Maastrichtian-age Upper Cretaceous Tremp Formation of Spain...
- Secernosaurus
Secernosaurus is a genus of herbivorous dinosaur. Secernosaurus was a hadrosaur, a "duck-billed" dinosaur which lived during the Late Cretaceous. Its fossils have been found in Argentina....
- Tanius
Tanius is a genus of hadrosaurid dinosaur. It lived in the Late Cretaceous of the People's Republic of China. The type species, described in 1929 by Carl Wiman, is T. sinensis. Other species originally assigned to Tanius have been moved to other genera, including Bactrosaurus and...
- Zhuchengosaurus
Zhuchengosaurus is a genus of hadrosaurid dinosaur from the Middle Cretaceous . It is currently the largest known ornithischian. Remains of several individuals, including skull bones, limb bones, and vertebrae, were found in Shandong, China...
- Dubious
In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application. Note that in the ICBN and ICNB the phrase "nomen dubium" has no status In zoological nomenclature, a nomen dubium (Latin for "doubtful name", plural nomina dubia) is a scientific name that...
hadrosaurids
- Arstanosaurus
Arstanosaurus was a genus of hadrosaurid dinosaur from the Santonian-Campanian-age Upper Cretaceous Bostobinskaya Formation, Kazakhstan. It has had a confusing history, being considered both a hadrosaurid and a ceratopsid, or both at the same time .-History:The genus was based on a maxilla , with...
- Cionodon
Cionodon was a genus of dinosaur from the Late Cretaceous Period. The type species, Cionodon arctatus lived in what is now present-day Colorado. It is classified as a hadrosaur, and was formally described by Edward Drinker Cope in 1874. It is a nomen dubium because it is based on very fragmentary...
- Diclonius
Diclonius is a genus of dinosaur from the Late Cretaceous. It was a hadrosaur based solely on teeth. Its fossils have been found in North America...
- Dysganus
Dysganus is the name given to a dubious genus of dinosaur from the Late Cretaceous. It was a ceratopsian. Its fossils have been found in Montana....
- Hypsibema
Hypsibema is a little-known genus of dinosaur from the Late Cretaceous . Its giant fossils were found in the U.S. states of North Carolina and Missouri...
- Mandschurosaurus
Mandschurosaurus is a hadrosaur taxon based on material from the Upper Cretaceous of Belye Kruchi, Manchuria. M. amurensis is based on a poorly preserved and incomplete skeleton collected by Russian scientists in 1914 from the banks of the Amur River...
- Microhadrosaurus
Microhadrosaurus is a genus of duckbill dinosaur from the Campanian or Maastrichtian-age Upper Cretaceous Yuanpu Formation of Guangdong, China...
- Orthomerus
Orthomerus is a genus of duckbill dinosaur from the Late Cretaceous of The Netherlands and possibly Ukraine. It is today an obscure genus, but in the past was conflated with the much better known Telmatosaurus-History:...
- Pteropelyx
Pteropelyx is a dubious genus of Late Cretaceous hadrosaurid dinosaur from the Judith River Formation of Montana, named by Edward Drinker Cope in 1889. Historically, several species were assigned to it, all based on extremely fragmentary remains, but there is no evidence to support these assignments...
- Thespesius
Thespesius is a dubious genus of hadrosaurid dinosaur based on two caudal vertebrae and a phalanx from the late Maastrichtian-age Upper Cretaceous Lance Formation of South Dakota...
- Trachodon
Trachodon is a dubious genus of hadrosaurid dinosaur based on teeth from the Campanian-age Upper Cretaceous Judith River Formation of Montana, U.S.A...
Phylogeny
Hadrosauridae was first defined as a
cladeA clade is a term used in modern alpha taxonomy, the scientific classification of living and fossil organisms, to describe a monophyletic group, defined as a group consisting of a single common ancestor and all its descendants.[The term "monophyletic group" is used in this article...]
, by Forster in a 1997 abstract, as simply "Labeosaurinae plus Hadrosaurinae and their most recent common ancestor." In 1998,
Paul SerenoPaul Callistus Sereno is an American paleontologist who is the discoverer of several new dinosaur species on several continents...
defined the clade Hadrosauridae as the most inclusive possible group containing
SaurolophusSaurolophus is a genus of large hadrosaurine duckbill that lived about 70 million years ago, in the Late Cretaceous of North America and Asia ; it is one of the few genera of dinosaurs known from multiple continents. It is distinguished by a spike-like crest which projects up and back from...
(a well-known hadrosaurine) and
ParasaurolophusParasaurolophus is a genus of ornithopod dinosaur from the Late Cretaceous Period of what is now North America, about 76-73 million years ago. It was a herbivore that walked both as a biped and a quadruped. Three species are recognized: P. walkeri , P...
(a well-known lambeosaurine), later emending the definition to include
HadrosaurusHadrosaurus is a dubious genus of hadrosaurid dinosaur. In 1858, a skeleton of a dinosaur from this genus was the first dinosaur skeleton known from more than isolated teeth to be found in North America. In 1868, it became the first ever mounted dinosaur skeleton...
, the type genus of the family, which
ICZNThe International Code of Zoological Nomenclature is both a book containing a set of rules and recommendations on the formal naming of animals, and that set itself. Among zoologists it is often referred to simply as "the Code"...
rules state must be included, despite its status as a
nomen dubium. According to some studies,{{Who|date=July 2007}} Sereno's definition would place a few other well-known hadrosaurs (such as
TelmatosaurusTelmatosaurus was a genus of basal hadrosaurid dinosaur from the Late Cretaceous. It was a relatively small hadrosaur, approximately 5 meters long, found in what is now Romania. The type species, Telmatosaurus transylvanicus, was described by Franz Nopcsa von Felső-Szilvás, in...
and
BactrosaurusBactrosaurus meaning "Bactrian lizard," "Bactria" + sauros = lizard)) was a herbivorous dinosaur that lived in east Asia during the late Cretaceous, 97 - 85 mya...
) outside the family, which led Horner
et al. (2004) to define the family to include
Telmatosaurus by default.
The following cladogram is after the 2004 review by
Jack HornerJohn "Jack" R. Horner is an American paleontologist who discovered and named Maiasaura, providing the first clear evidence that some dinosaurs cared for their young. He is one of the best-known paleontologists in the United States...
,
David B. WeishampelProfessor David B. Weishampel is an American palaeontologist in the Center for Functional Anatomy and Evolution at Johns Hopkins University School of Medicine. Weishampel received his Ph.D. in Geology from the University of Pennsylvania in 1981...
, and Catherine Forster, in the second edition of
The Dinosauria.
{{clade| style=font-size:85%;line-height:85%
|label1=
Hadrosauridae
|1={{clade
|1=
TelmatosaurusTelmatosaurus was a genus of basal hadrosaurid dinosaur from the Late Cretaceous. It was a relatively small hadrosaur, approximately 5 meters long, found in what is now Romania. The type species, Telmatosaurus transylvanicus, was described by Franz Nopcsa von Felső-Szilvás, in...
|label2=
Euhadrosauria
|2={{clade
|label1= Hadrosaurinae
|1={{clade
|1=
LophorhothonLophorhothon is the first genus of dinosaur discovered in Alabama. Remains of this small, poorly-known hadrosaurine euhadrosaurid dinosaur were first discovered during the 1940s, from extensive erosional outcrops of the lower unnamed member of the Mooreville Chalk Formation in Dallas County, west...
|label2=
unnamed
|2={{clade
|label1=
unnamed
|1={{clade
|1=
ProsaurolophusProsaurolophus is a genus of hadrosaurid dinosaur from the Late Cretaceous of North America. It is known from the remains of at least 25 individuals belonging to two species, including skulls and skeletons, but it remains obscure...
|label2=
unnamed
|2={{clade
|1=
GryposaurusGryposaurus was a genus of duckbilled dinosaur that lived about 83 to 75 million years ago, in the Late Cretaceous of North America...
|label2=
unnamed
|2={{clade
|1=
EdmontosaurusEdmontosaurus is a genus of crestless duck-billed dinosaur. The fossils of this animal have been found in rocks of western North America that date from the late Campanian stage to the end of the Maastrichtian stage of the Cretaceous Period, between 73 and 65.5 million years ago...
|label2=
unnamed
|2={{clade
|1=
BrachylophosaurusBrachylophosaurus Brachylophosaurus Brachylophosaurus ( or ; meaning "short-crested lizard" (Greek brachy = short + lophos = crest + sauros = lizard, referring to its small crest) was a mid-sized member of the hadrosaurid family of dinosaurs...
|2=
MaiasauraMaiasaura is a large duck-billed dinosaur genus that lived in the area currently covered by the state of Montana in the Upper Cretaceous Period , about 74 million years ago.-Description:...
}}
}}
}}
}}
|label2=
unnamed
|2={{clade
|1=
"Kritosaurus" australisKritosaurus is an incompletely known but historically important genus of hadrosaurid dinosaur...
|2=
NaashoibitosaurusNaashoibitosaurus is a genus of hadrosaurid dinosaur that lived about 73 million years ago, in the Late Cretaceous, and was found in the Kirtland Formation of the San Juan Basin in New Mexico, United States. Only a partial skeleton has been found to date...
|3=
SaurolophusSaurolophus is a genus of large hadrosaurine duckbill that lived about 70 million years ago, in the Late Cretaceous of North America and Asia ; it is one of the few genera of dinosaurs known from multiple continents. It is distinguished by a spike-like crest which projects up and back from...
}}
}}
}}
|label2= Lambeosaurinae
|2={{clade
|1=
TsintaosaurusTsintaosaurus is a genus of hadrosaurid dinosaur from China. It was about long, tall and weighed 3 tons. The type species is T. spinorhinus, first described by C. C. Young in 1958....
|label2=
unnamed
|2={{clade
|1=
ParasaurolophusParasaurolophus is a genus of ornithopod dinosaur from the Late Cretaceous Period of what is now North America, about 76-73 million years ago. It was a herbivore that walked both as a biped and a quadruped. Three species are recognized: P. walkeri , P...
|label2=
unnamed
|2={{clade
|1=
LambeosaurusLambeosaurus is a genus of hadrosaurid dinosaur that lived about 76 to 75 million years ago, in the Late Cretaceous Period of North America. This bipedal/quadrupedal, herbivorous dinosaur is known for its distinctive hollow cranial crest, which in the best-known species resembled a hatchet...
|2=
CorythosaurusCorythosaurus Corythosaurus Corythosaurus was a genus of duck-billed dinosaur from the Upper Cretaceous Period, about 75 million years ago...
|3=
HypacrosaurusHypacrosaurus was a genus of duckbill dinosaur similar in appearance to Corythosaurus. Like Corythosaurus, it had a tall, hollow rounded crest, although not as large and straight...
}}
}}
}}
}}
}}
}}
Hadrosaurine cladogram
Hadrosauridae has not been subjected to as many phylogenetic analyses as other dinosaur groups, so other workers may find quite different phylogenies. Gates and Sampson (2007) published the following alternate cladogram of Hadrosaurinae in their description of
Gryposaurus monumentensis:
{{clade| style=font-size:85%;line-height:85%
|label1=
unnamed
|1={{clade
|1=
TelmatosaurusTelmatosaurus was a genus of basal hadrosaurid dinosaur from the Late Cretaceous. It was a relatively small hadrosaur, approximately 5 meters long, found in what is now Romania. The type species, Telmatosaurus transylvanicus, was described by Franz Nopcsa von Felső-Szilvás, in...
|label2=
unnamed
|2={{clade
|1=
CorythosaurusCorythosaurus Corythosaurus Corythosaurus was a genus of duck-billed dinosaur from the Upper Cretaceous Period, about 75 million years ago...
(Lambeosaurinae)
|label2=
unnamed
|2={{clade
|1=
LophorhothonLophorhothon is the first genus of dinosaur discovered in Alabama. Remains of this small, poorly-known hadrosaurine euhadrosaurid dinosaur were first discovered during the 1940s, from extensive erosional outcrops of the lower unnamed member of the Mooreville Chalk Formation in Dallas County, west...
|label2=
unnamed
|2={{clade
|label1=
unnamed
|1={{clade
|1=
EdmontosaurusEdmontosaurus is a genus of crestless duck-billed dinosaur. The fossils of this animal have been found in rocks of western North America that date from the late Campanian stage to the end of the Maastrichtian stage of the Cretaceous Period, between 73 and 65.5 million years ago...
|label2=
unnamed
|2={{clade
|1=
ProsaurolophusProsaurolophus is a genus of hadrosaurid dinosaur from the Late Cretaceous of North America. It is known from the remains of at least 25 individuals belonging to two species, including skulls and skeletons, but it remains obscure...
|2=
SaurolophusSaurolophus is a genus of large hadrosaurine duckbill that lived about 70 million years ago, in the Late Cretaceous of North America and Asia ; it is one of the few genera of dinosaurs known from multiple continents. It is distinguished by a spike-like crest which projects up and back from...
}}
}}
|label2=
unnamed
|2={{clade
|1=
NaashoibitosaurusNaashoibitosaurus is a genus of hadrosaurid dinosaur that lived about 73 million years ago, in the Late Cretaceous, and was found in the Kirtland Formation of the San Juan Basin in New Mexico, United States. Only a partial skeleton has been found to date...
|label2=
unnamed
|2={{clade
|1=
GryposaurusGryposaurus was a genus of duckbilled dinosaur that lived about 83 to 75 million years ago, in the Late Cretaceous of North America...
|label2=
unnamed
|2={{clade
|1=
BrachylophosaurusBrachylophosaurus Brachylophosaurus Brachylophosaurus ( or ; meaning "short-crested lizard" (Greek brachy = short + lophos = crest + sauros = lizard, referring to its small crest) was a mid-sized member of the hadrosaurid family of dinosaurs...
|2=
MaiasauraMaiasaura is a large duck-billed dinosaur genus that lived in the area currently covered by the state of Montana in the Upper Cretaceous Period , about 74 million years ago.-Description:...
}}
}}
}}
}}
}}
}}
}}
}}
Lambeosaurine cladogram
The following cladogram is after the 2007 redescription of
Lambeosaurus magnicristatus (Evans and Reisz, 2007):
{{clade| style=font-size:85%;line-height:85%
|label1=
Hadrosauridae
|1={{clade
|1=Hadrosaurinae
|label2= Lambeosaurinae
|2={{clade
|1=
AralosaurusAralosaurus meaning "Aral Sea lizard", because it was found in the Aral Sea was a genus of hadrosaurid dinosaur which lived during the Late Cretaceous of what is now Kazakhstan...
|label2=
unnamed
|2={{clade
|1=
TsintaosaurusTsintaosaurus is a genus of hadrosaurid dinosaur from China. It was about long, tall and weighed 3 tons. The type species is T. spinorhinus, first described by C. C. Young in 1958....
|label2=
unnamed
|2={{clade
|1=
JaxartosaurusJaxartosaurus is a genus of hadrosaurid dinosaur similar to Corythosaurus which lived during the Late Cretaceous. Its fossils were found in Kazakhstan and China. It had a large, helmet-like crest that it may have used for visual identification, or to vocalize with members of the same herd.The type...
|label2=
unnamed
|2={{clade
|1=
AmurosaurusAmurosaurus is a genus of lambeosaurine hadrosaurid dinosaur found in the Late Cretaceous of eastern Asia. Like most lambeosaurs, it would have been a primarily bipedal herbivore with a "duckbill" shaped snout and a hollow crest on top of its head, although such a crest has not been found...
|label2=
unnamed
|2={{clade
|label1=
unnamed
|1={{clade
|1=
CharonosaurusCharonosaurus is the name of a genus of dinosaur whose fossils were discovered by Godefroit, Zan & Jin in 2000 on the south bank of the Amur River, dividing China from Russia.-Description:...
|label2=
unnamed
|2={{clade
|1=
Parasaurolophus cyrtocristatusParasaurolophus is a genus of ornithopod dinosaur from the Late Cretaceous Period of what is now North America, about 76-73 million years ago. It was a herbivore that walked both as a biped and a quadruped. Three species are recognized: P. walkeri , P...
|label2=
unnamed
|2={{clade
|1=
P. tubicenParasaurolophus is a genus of ornithopod dinosaur from the Late Cretaceous Period of what is now North America, about 76-73 million years ago. It was a herbivore that walked both as a biped and a quadruped. Three species are recognized: P. walkeri , P...
|2=
P. walkeriParasaurolophus is a genus of ornithopod dinosaur from the Late Cretaceous Period of what is now North America, about 76-73 million years ago. It was a herbivore that walked both as a biped and a quadruped. Three species are recognized: P. walkeri , P...
}}
}}
}}
|label2=
unnamed
|2={{clade
|1=
NipponosaurusNipponosaurus is a lambeosaurine hadrosaurid from Asia. The holotype was discovered in November 1934 during the construction of a hospital on Karafuto Prefecture , and additional material belonging to the specimen was recovered in the summer of 1937...
|label2=
unnamed
|2={{clade
|label1=
unnamed
|1={{clade
|1=
Lambeosaurus lambeiLambeosaurus is a genus of hadrosaurid dinosaur that lived about 76 to 75 million years ago, in the Late Cretaceous Period of North America. This bipedal/quadrupedal, herbivorous dinosaur is known for its distinctive hollow cranial crest, which in the best-known species resembled a hatchet...
|2=
L. magnicristatusLambeosaurus is a genus of hadrosaurid dinosaur that lived about 76 to 75 million years ago, in the Late Cretaceous Period of North America. This bipedal/quadrupedal, herbivorous dinosaur is known for its distinctive hollow cranial crest, which in the best-known species resembled a hatchet...
}}
|label2=
unnamed
|2={{clade
|1=
CorythosaurusCorythosaurus Corythosaurus Corythosaurus was a genus of duck-billed dinosaur from the Upper Cretaceous Period, about 75 million years ago...
|2=
OlorotitanOlorotitan was a genus of lambeosaurine duckbilled dinosaur from the middle or late Maastrichtian-age Late Cretaceous Tsagayan Formation beds located in Kundur, Amur Region, Far Eastern Russia. The remains, consisting of a nearly complete skeleton, were described by Pascal Godefroit et al. in...
|label3=
unnamed
|3={{clade
|1=
Hypacrosaurus altispinusHypacrosaurus was a genus of duckbill dinosaur similar in appearance to Corythosaurus. Like Corythosaurus, it had a tall, hollow rounded crest, although not as large and straight...
|2=
H. stebingeriHypacrosaurus was a genus of duckbill dinosaur similar in appearance to Corythosaurus. Like Corythosaurus, it had a tall, hollow rounded crest, although not as large and straight...
}}
}}
}}
}}
}}
}}
}}
}}
}}
}}
}}
Diet
{{Main|Hadrosaur diet}}
While studying into the chewing methods of hadrosaurids in 2009, the paleontologists Vincent Williams, Paul Barrett, and
Mark PurnellDr Mark Andrew Purnell is a British palaeontologist, Reader of Geology at the University of Leicester.Purnell is an expert in conodont biostratigraphy and conodont palaeobiology, focussing especially on attempts to uncover the function of conodont elements...
also found that hadrosaurs likely grazed on horsetails and vegetation close to the ground, rather than browsing higher-growing leaves and twigs. This conclusion was based upon the evenness of scratches on hadrosaur teeth, which suggested the hadrosaur used the same series of jaw motions over and over again. As a result, the study determined that the hadrosaur diet was probably made of leaves and lacked the bulkier items such as twigs or stems, which might have required a different chewing method and created different wear patterns. However, Purnell said these conclusions were less secure than the more conclusive evidence regarding the motion of teeth while chewing.
The hypothesis that hadrosaurs were likely grazers rather than browsers appears to contradicts previous findings from preserved stomach contents found in the fossilized guts in previous hadrosaurs studies. The most recent such finding before the publication of the Purnell study was conducted in 2008, when a team led by
University of Colorado at BoulderThe University of Colorado at Boulder is a public research university located in Boulder, Colorado. It is the flagship university of the University of Colorado system and was founded five months before Colorado was admitted to the union in 1876...
graduate student Justin S. Tweet found a homogeneous accumulation of millimeter-scale leaf fragments in the gut region of a well-preserved partially-grown
BrachylophosaurusBrachylophosaurus Brachylophosaurus Brachylophosaurus ( or ; meaning "short-crested lizard" (Greek brachy = short + lophos = crest + sauros = lizard, referring to its small crest) was a mid-sized member of the hadrosaurid family of dinosaurs...
. As a result of that finding, Tweet concluded in September 2008 that the animal was likely a browser, not a grazer. In response to such findings, Purnell said preserved stomach contents are questionable because they do not necessarily represent the usual diet of the animal. The issue remains a subject of debate.
CoproliteA coprolite is fossilized animal dung. Coprolites are classified as trace fossils as opposed to body fossils, as they give evidence for the animal's behaviour rather than morphology. The name is derived from the Greek words κοπρος / kopros meaning 'dung' and λιθος / lithos meaning 'stone'. They...
s (fossilized droppings) of some Late
CretaceousThe Cretaceous , Latin language for "chalky", 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 on the Jurassic period and is followed by the Paleogene period of the...
hadrosaurs show that the animals sometimes deliberately ate rotting wood. Wood itself is not nutritious, but decomposing wood would have contained fungi, decomposed wood material and
detritusDetritus is a biological term used to describe dead or waste organic material.Detritus may also refer to:* Detritus , a geological term used to describe the particles of rock produced by weathering...
-eating
invertebrateAn invertebrate is an animal without a vertebral column. The group includes 95% of all animal species — all animals except those in the Chordate subphylum Vertebrata ....
s, all of which would have been nutritious.
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