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Information about Caenagnathid

Caenagnathids
Fossil range: Late Cretaceous
Conservation status
Extinct (fossil)
Scientific classification
Kingdom:Animalia
Phylum:Chordata
Class:Sauropsida
Superorder:Dinosauria
Order:Saurischia
Infraorder:Oviraptorosauria
Superfamily:Caenagnathoidea
Family:Caenagnathidae
Sternberg, 1940
Genera
Synonyms
  • Elmisauridae Osmólska, 1981
Caenagnathidae ("recent jaws") is a family of bird-like theropod dinosaurs within the clade Oviraptorosauria, first coined as an order of advanced flightless birds by Charles Hazelius Sternberg in 1940.[1] While more advanced than earlier oviraptorosaurs like Caudipteryx, caenagnathids were fairly primitive compared with their close relatives the oviraptorids. Whereas oviraptorids had highly shortened snouts, caenagnathid jaws were long and unspecialized (though they still possessed the distinctive beaks of other oviraptorosaurs). Additionally, caenagnathids had typical theropod arms, with a relatively short third finger--all traits that were modified in the oviraptorids, which had longer arms and fingers, as well as comparatively short legs.

The family Caenagnathidae, together with its sister group the Oviraptoridae, comprises the superfamily Caenagnathoidea. In phylogenetic taxonomy, the clade Caenagnathidae is defined as the most inclusive group containing Chirostenotes but not Oviraptor. Though only six species of caenagnathids are currently recognized by paleontologists, the family has a notably confused taxonomic history. Much of this centers on the first caenagnathid to be described, Chirostenotes. Due to the poor preservation of most caenagnathid remains and resulting misidentifications, different bones and different specimens of Chirostenotes have historically been assigned to a number of different species. One of these was the family's namesake, Caenagnathus. While Caenagnathus is today considered a junior synonym of Chirostenotes, it was the first for which a family was named, so while the genus name Caenagnathus is no longer in use, the family name Caenagnathidae remains valid.

The name Caenagnathus (and hence Caenagnathidae) means "recent jaws"--when first discovered, it was thought that caenagnathids were close relatives of paleognath birds (such as the ostrich) based on features of the lower jaw. Since it would be unusual to find a recent group of birds in the Cretaceous, the name "recent jaws" was applied. Most paleontologists, however, now think that the birdlike features of the jaw were acquired convergently with modern birds.[2][3]

Species

Today, Caenagnathidae usually contains six species in three genera. However, a few paleontologists consider Elmisaurus elegans to be a junior synonym of Chirostenotes, as they both occur in the same North American locality, far from the Asian species Elmisaurus rarus (Sues, 1997). The genus Caenagnathasia was originally placed in this family, but it is probably more primitive, lying outside both Caenagnathidae and Oviraptoridae within the superfamily Caenagnathoidea.[4] Additionally, Maryańska, Osmólska, and Wołsan considered the oviraptorosaur with a pygostyle, Nomingia, a member of this family.[5]

Caenagnathidae includes -
  • Chirostenotes pergracilis, the first known caenagnathid, described initially from two hands and a partial lower arm. Many subsequently named species have been referred to this species, adding to the known fossil material.[6]
  • Chirostenotes sternbergi, a more gracile caenagnathid. Some consider Elmisaurus elegans to be the same animal, as both are smaller and more slender than C. pergracilis. It is also possible that this species represents a different gender of the larger C. pergracilis specimens.
  • Chirostenotes sp., a possible new species, has been identified from part of a lower jaw found in Montana, but not named.[4]
  • Elmisaurus rarus, the only known Asian caenagnathid (excluding Caenagnathasia), is known only from elements of the foot.
  • Elmisaurus elegans, a smaller Canadian species originally described as a species of Ornithomimus. It may be the same species as Chirostenotes.
  • The "Triebold caenagnathid", an infamous possible new species or genus collected by Triebold Paleontology of South Dakota. Known from two excellently preserved specimens, this species, having been obtained by private collectors, was put up for sale, making its scientific future unknown until it was acquired by the Carnegie Museums of Pittsburgh. An apparently giant species with a well preserved skull and evidence of an oviraptorid-like crest, it is currently awaiting a published description.

References

1. ^ Sternberg, R.M. (1940). "A toothless bird from the Cretaceous of Alberta." Journal of Paleontology, 14 (1): 81-85.
2. ^ Cracraft, J. (1971). "Caenagnathiformes: Cretaceous birds convergent in jaw mechanism to dicynodont reptiles." Journal of Paleontology, 45: 805-809.
3. ^ Barsbold, R., Maryańska, T., and Osmólska, H. (1990). "Oviraptorosauria." pg. 249-258 in Weishampel, Dodson, and Osmolska (eds.) The Dinosauria, University of California Press (Berkeley).
4. ^ Currie, P.J., Godfrey, S.J., and Nessov, L.A. (1994). "New caenagnathid (Dinosauria: Theropoda) specimens from the Upper Cretaceous of North America and Asia." Canadian Journal of Earth Sciences -- Revue de Canadienne des Sciences de la Terre, 30: 2255-2272.
5. ^ Maryańska, T., Osmólska, H., and Wołsan, M. (2002). "Avialan status for Oviraptorosauria." Acta Palaeontologica Polonica, 47 (1): 97-116.
6. ^ Sues, H.-D. (1997). "On Chirostenotes, a Late Cretaceous oviraptorosaur (Dinosauria: Theropoda) from western North America." Journal of Vertebrate Paleontology, 17 (4): 698-716.

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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conservation status of a species is an indicator of the likelihood of that species continuing to survive either in the present day or the future. Many factors are taken into account when assessing the conservation status of a species: not simply the number remaining, but the
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For other uses of the term, see Fossil (disambiguation)


FOSSIL is a standard for allowing serial communication for telecommunications programs under the DOS operating system.
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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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Saurischia
Seeley, 1887

Suborders
  • Theropoda
  • Sauropodomorpha


Saurischia (from the Greek sauros (σαυρος) meaning 'lizard' and ischion (
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Oviraptorosauria
Barsbold, 1976

Families
  • Avimimidae
  • Caudipteridae
  • Caenagnathidae
  • Oviraptoridae


Oviraptorosaurs
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Charles Hazelius Sternberg
Born 1850

Died 1943

Nationality USA
Field Paleontology Charles Hazelius Sternberg
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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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Caenagnathasia

Binomial name
Caenagnathasia martinsoni
Currie, Godfrey, & Nessov 1993

Caenagnathasia
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Caenagnathinae
Sternberg, 1940

Genus: Chirostenotes
Gilmore, 1924

Species
  • C. pergracilis (type)
  • C.

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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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Elmisaurus

Binomial name
Elmisaurus rarus
Osmólska, 1981

Elmisaurus is the name given to a genus of dinosaur from the Late Cretaceous. It was a theropod belonging to the Oviraptorosauria.
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Nomingia

Binomial name
Nomingia gobiensis
Barsbold et al., 2000

Nomingia was a genus of oviraptorosaurian dinosaur hailing from the Late Cretaceous Bugin Tsav Beds.
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In scientific nomenclature, synonyms are different scientific names used for a single taxon. Usage and terminology are different for zoology and botany.

Zoology

In zoological nomenclature, synonyms are different scientific names that pertain to the same taxon, for example
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Theropoda
Marsh, 1881

Infraorders
  • Carnosauria
  • Ceratosauria
  • Deinonychosauria
  • Ornithomimosauria
  • Oviraptorosauria


Theropods ('beast feet') are a group of bipedal saurischian dinosaurs.
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Dinosauria *
Owen, 1842

Orders & Suborders
  • Ornithischia
  • Cerapoda
  • Thyreophora
  • Saurischia

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Oviraptorosauria
Barsbold, 1976

Families
  • Avimimidae
  • Caudipteridae
  • Caenagnathidae
  • Oviraptoridae


Oviraptorosaurs
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Charles Hazelius Sternberg
Born 1850

Died 1943

Nationality USA
Field Paleontology Charles Hazelius Sternberg
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Caudipteridae
Zhou & Wang, 2000

Genus: Caudipteryx
Ji et al., 1998

Species
  • C. zoui (type)
  • C.

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Oviraptoridae
Barsbold, 1976

Genera

See text

Oviraptoridae is a group of bird-like maniraptoran dinosaurs. They are currently known from Mongolia and China, although there is an unpublished report from Montana.
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Phylogenetic nomenclature is an alternative to rank-based nomenclature. Its two defining features are the use of phylogenetic definitions of biological taxon names, and the lack of obligatory ranks.
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Caenagnathinae
Sternberg, 1940

Genus: Chirostenotes
Gilmore, 1924

Species
  • C. pergracilis (type)
  • C.

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Paleognathae
Pycraft, 1900

Orders

Primary Classification
  • Lithornithiformes
  • Dinornithiformes
  • Aepyornithiformes
  • Struthioniformes
  • Rheiformes
  • Casuariiformes
  • Apterygiformes
  • Tinamiformes

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Struthionidae
Vigors, 1825

Genus: Struthio
Linnaeus, 1758

Species: S.
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In evolutionary biology, convergent evolution is the process whereby organisms not closely related (not monophyletic), independently evolve similar traits as a result of having to adapt to similar environments or ecological niches[1].
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