Anatotitan

Anatotitan
Fossil range: Late Cretaceous

Scientific classification
Kingdom:Animalia
Phylum:Chordata
Class:Sauropsida
Superorder:Dinosauria
Order:Ornithischia
Family:Hadrosauridae
Subfamily:Hadrosaurinae
Tribe:Edmontosaurini
Genus:Anatotitan
Chapman & Brett-Surman, 1990
Species
  • A. copei (type)
  • A. longiceps (Marsh, 1897) Olshevsky, 1991


Anatotitan (a-NAT-o-TIE-tan; "duck titan") is a genus of hadrosaurid ornithopod dinosaur from the very end of the Cretaceous Period, in what is now North America. It was a very large animal, nearly 12 meters (40 feet) in length, with an extremely long and low skull.[1] Anatotitan exhibits one of the most striking examples of the "duckbill" snout common to hadrosaurs.

Remains

This dinosaur is known from at least five specimens discovered in the U.S. states of South Dakota and Montana. Several of these specimens are extremely complete skeletons with well-preserved skulls. Several unique features were used to separate Anatotitan from other hadrosaurs when it was first described, many of them relating to its enormous skull. The skull is longer and lower proportionally than any other known hadrosaur, with one skull measuring over 1.18 meters (46 inches) long. The "duckbill" portion of the muzzle is also wider than in any other hadrosaur, almost as wide as the skull itself. Inside the mouth, there is a large diastema, or toothless section, which is also larger than in any other hadrosaur.

Remains of Anatotitan have been preserved in the Hell Creek and Lance Formations, which are dated to the late Maastrichtian stage of the Late Cretaceous Period, representing the last three million years before the extinction of the dinosaurs (68 to 65 million years ago).

Taxonomic history

Like many dinosaurs, Anatotitan has a long and somewhat confusing taxonomic history. The holotype, or original specimen, was a complete skull and skeleton found in 1882 by famous American paleontologist Edward Drinker Cope. Cope had previously discovered other specimens and placed them in the genus Diclonius, which was synonymized with Trachodon in 1902. Two of these extremely complete specimens were famously mounted side-by-side in the American Museum of Natural History in New York City under the name Trachodon mirabilis.

Meanwhile, another hadrosaur had been discovered in the western United States, which Othniel Charles Marsh named Claosaurus annectens in 1892. However, in 1942, paleontologists Richard Swann Lull and Nelda Wright recognized that this species was very different from the type species of Claosaurus and needed to have its own name. They created the new genus Anatosaurus ("duck lizard") and made Marsh's species the type species, calling it Anatosaurus annectens. Also, Lull and Wright recognized that the species Trachodon mirabilis was originally based on just a tooth and that the three skeletons referred to it in 1902 did not necessarily belong to the same species. A new species was created for them, which was called Anatosaurus copei, named after Edward Drinker Cope, who originally described the specimens.

Enlarge picture
Life restoration of Anatotitan copei.
Most modern paleontologists now include Anatosaurus annectens in the genus Edmontosaurus, as the species Edmontosaurus annectens. However, in 1990, paleontologists Ralph Chapman and Michael Brett-Surman argued that Anatosaurus copei was different enough from Edmontosaurus that it should be in a separate genus. Because the type species of Anatosaurus had already been synonymized with Edmontosaurus, a new generic name was needed. They created the name Anatotitan, from the Latin anas ("duck") and the Greek Titan, which was a race of mythological divine giants. This name refers both to the animal's size and to its wide "duckbill" snout.

The name Anatotitan was originally published in the Ph.D. thesis of Brett-Surman, but theses do not count as official publications according to ICZN regulations, so the official first publication of the name was in a separate 1990 paper authored by Chapman and Brett-Surman.

Today, debate continues as to whether Anatotitan copei should be in its own genus or whether it should be a species of Edmontosaurus. Some scientists believe that the Anatotitan specimens are in fact individuals of Edmontosaurus annectens whose skulls have been crushed during preservation and appear to be much longer and lower than they actually were (Horner et al., 2004).

Whether or not Anatotitan and Edmontosaurus are separate genera, they are very closely related and are both members of the subfamily Hadrosaurinae within the family Hadrosauridae. Shantungosaurus is another gigantic hadrosaur from China which may also be related to these North American dinosaurs.

Anatotitan in popular culture

Enlarge picture
Anatotitan as seen in Walking with Dinosaurs.


Although Anatotitan is not as well-known as many of its sister dinosaur taxa, the genus has appeared occasionally in popular media, and has become a representation of dinosaurs in popular culture. Anatotitan appeared in the final episode of the BBC documentary series Walking with Dinosaurs, "Death of a Dynasty".[2] Director and producer Jasper James depicted Anatotitan as the last duck-billed dinosaur genus and as prey for the carnivorous theropod Tyrannosaurus rex. Anatotitan also appeared in the American nature documentary When Dinosaurs Roamed America as a peaceful herbivorous dinosaur.

References

1. ^ Sues, Hans-Dieter (1997). "ornithopods", in James Orville Farlow and M. K. Brett-Surman (eds.): The Complete Dinosaur. Bloomington: Indiana University Press, p.338. ISBN 0-253-33349-0. 
2. ^ Walking with Dinosaurs: Celluloid (and Digital) Dinosaurs History of Dinosaur Movies (and Television Documentaries). 2000. Retrieved 2007-06-06.
  • Brett-Surman, M.K., 1989. A revision of the Hadrosauridae (Reptilia: Ornithischia) and their evolution during the Campanian and Maastrichtian. Ph.D. dissertation, George Washington University, Washington, D.C.. pp.1-272.
  • Chapman, R.E. & Brett-Surman, M.K. 1990. Morphometric observations on hadrosaurid ornithopods. In: Carpenter, K. & Currie, P.J. (Eds.). Dinosaur Systematics: Approaches and Perspectives. Cambridge: Cambridge University Press. Pp. 163-178.
  • Horner, J.R., Weishampel, D.B., & Forster, C.A. 2004. Hadrosauridae. In: Weishampel, D.B., Dodson, P., & Osmolska, H. (Eds.). The Dinosauria (2nd Edition). Berkeley: University of California Press. Pp. 438-463.

External links

Late Cretaceous (100mya - 65mya) refers to the second half of the Cretaceous Period, named after the famous white chalk cliffs of southern England, which date from this time. Rocks deposited during the Late Cretaceous Period are referred to as the Upper Cretaceous Series.
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American Museum of Natural History is a landmark on the Upper West Side, Manhattan, New York, USA. The museum has a scientific staff of more than 200, and sponsors over 100 special field expeditions each year.
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Scientific classification or biological classification is a method by which biologists group and categorize species of organisms. Scientific classification also can be called scientific taxonomy, but should be distinguished from folk taxonomy, which lacks scientific basis.
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Chordata
Bateson, 1885

Typical Classes

See below

Chordates (phylum Chordata) are a group of animals that includes the vertebrates, together with several closely related invertebrates.
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Sauropsida*
Goodrich, 1916

Subclasses
  • Anapsida
  • Diapsida
Synonyms
  • Reptilia Laurenti, 1768
Reptiles are tetrapods and amniotes, animals whose embryos are surrounded by an amniotic membrane, and members of the class
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Dinosauria *
Owen, 1842

Orders & Suborders
  • Ornithischia
  • Cerapoda
  • Thyreophora
  • Saurischia

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Ornithischia
Seeley, 1888

Suborders
  • Cerapoda
  • Thyreophora


Ornithischia or Predentata is an order of beaked, herbivorous dinosaurs.
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Hadrosauridae
Cope, 1869

Subfamilies
  • Hadrosaurinae Cope, 1869
  • Lambeosaurinae Parks, 1923
Synonyms
  • Trachodontidae Lydekker, 1888
  • Saurolophidae Brown, 1914
  • Lambeosauridae Parks, 1923 vide Horner, 1990

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Hadrosauridae
Cope, 1869

Subfamilies
  • Hadrosaurinae Cope, 1869
  • Lambeosaurinae Parks, 1923
Synonyms
  • Trachodontidae Lydekker, 1888
  • Saurolophidae Brown, 1914
  • Lambeosauridae Parks, 1923 vide Horner, 1990

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Hadrosauridae
Cope, 1869

Subfamilies
  • Hadrosaurinae Cope, 1869
  • Lambeosaurinae Parks, 1923
Synonyms
  • Trachodontidae Lydekker, 1888
  • Saurolophidae Brown, 1914
  • Lambeosauridae Parks, 1923 vide Horner, 1990

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species is one of the basic units of biological classification. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring.
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In biology, a type is that which fixes a name to a taxon. Depending on the nomenclature code which is applied to the organism in question, a type may be a specimen, culture, illustration, description or taxon.
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Othniel Charles Marsh (October 29, 1831 - March 18, 1899) was one of the pre-eminent paleontologists of the 19th century, who discovered and named many fossils found in the American West.

Marsh was born in Lockport, New York.
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genus (plural: genera) is part of the Latinized name for an organism. It is a name which reflects the classification of the organism by grouping it with other closely similar organisms.
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Hadrosauridae
Cope, 1869

Subfamilies
  • Hadrosaurinae Cope, 1869
  • Lambeosaurinae Parks, 1923
Synonyms
  • Trachodontidae Lydekker, 1888
  • Saurolophidae Brown, 1914
  • Lambeosauridae Parks, 1923 vide Horner, 1990

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Ornithopoda
Marsh, 1881

Families
  • Hypsilophodontidae*
  • Rhabdodontidae
  • Dryosauridae
  • Camptosauridae
  • Iguanodontidae
  • Hadrosauridae


Ornithopods
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Dinosauria *
Owen, 1842

Orders & Suborders
  • Ornithischia
  • Cerapoda
  • Thyreophora
  • Saurischia

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The Cretaceous Period is one of the major divisions of the geologic timescale, reaching from the end of the Jurassic Period (i.e. from 145.5 ± 4.0 million years ago (Ma)) to the beginning of the Paleocene epoch of the Tertiary Period (about 65.5 ± 0.3 Ma).
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A geologic period is a subdivision of geologic time that divides an era into smaller timeframes. The equivalent term used to demarcate rock layers and the fossil record is the system; thus the rocks of the Devonian System were laid down during the Devonian Period.
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North America is a continent [1] in the Earth's northern hemisphere and (chiefly) 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 south and west
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skull is a bony structure found in many animals which serves as the general framework for the head. The skull supports the structures of the face and protects the head against injury.

The skull can be subdivided into two parts: the cranium and the mandible.
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Nickname(s): Treasure State, Big Sky Country
Motto(s): Oro y plata (Gold and silver)

Official language(s) English

Capital Helena
Largest city
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The 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.
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The Lance Formation is a division of Late Cretaceous rocks in the western United States. Named after Lance Creek, Wyoming, the microvertebrate fossils and dinosaurs represent important components of the latest Mesozoic vertebrate faunas.
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The Maastrichtian is the last stage of the Cretaceous period, and therefore of the Mesozoic era. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma (million years ago).
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Late Cretaceous (100mya - 65mya) refers to the second half of the Cretaceous Period, named after the famous white chalk cliffs of southern England, which date from this time. Rocks deposited during the Late Cretaceous Period are referred to as the Upper Cretaceous Series.
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