Caenagnathidae

Head reconstruction of Chirostenotes

• North America
• Asia

The Caenagnathidae are a systematic group of dinosaurs within the Oviraptorosauria. As with all Oviraptorosauria there were small to medium-sized, very bird-like feathered theropods and probably with a much shorter tail and a toothless beak. While the other group of Oviraptorosauria that Oviraptoridae, showed very short skull and deep pine, had the Caenagnathidae long and thin jaws and long legs. The Caenagnathidae is occupied from the Late Cretaceous of North America and Asia.

Fossil record and Features

In contrast to Oviraptoridae, which is known by numerous well-preserved and complete skeletons, have been described by the Caenagnathidae only few and fragmentary remains. Thus, by this group only a fragmentary skull, some of the lower jaw and some isolated bones found the skull to the subsequent residual skeleton ( Postkranium ) known. Finds that any of the Caenagnathidae can also be attributed to close Nomingia with one, who among other things a spine in the natural anatomical composite is obtained. Additional material waiting meanwhile on a scientific description, including a tentatively called " Trie Bold Caenagnathide " designated species whose skeleton is known for the most part.

Due to the incomplete fossil material, a single feature is only known that undoubtedly is characteristic of the group ( synapomorphy ) and sets them apart from other groups: the paired lower jaw is fused at the symphysis. Other synapomorphies could include the lack of an additional Mandibularfensters and arctometatarsale position of the foot: So the third metatarsal bone of the front was regarded as visible only in the lower part of the midfoot, while he was concealed by the contacting second and fourth metatarsal bones in the upper part. A Arctometatarsus found in Caenagnathiden, Avimimus and various other groups outside the Oviraptorosauria, but absent in the Oviraptoridae.

History of Research

The Caenagnathidae was first described by Sternberg in 1940. The name is derived from the Caenagnathidae now invalid genus Caenagnathus and means something like "modern pine " The jawbone of Caenagnathus were very similar to those in the present Urkiefervögel ( Paleognathae ). However, since it is unusual to discover the jaw of a modern bird group in the Cretaceous period, called the dinosaur Caenagnathus - " modern pine ". Today Caenagnathus regarded as identical with Chirostenotes; because Chirostenotes but was described before Caenagnathus, Chirostenotes is the only valid today Name ( priority rule).

Species

• Chirostenotes pergracilis
• Chirostenotes Sternbergi
• Chirostenotes sp., A possible new, yet unnamed species from Montana ( USA), which is known fragment of a lower jaw.
• Caenagnathasia martin soni
• Elmisaurus elegans
• The " Trie Bold Caenagnathide ", a yet unnamed new, very well-preserved type that is based on two partial skeletons, which were discovered in South Dakota (USA).
• Hagryphus giganteus
• ? Nomingia gobiensis, another possible Caenagnathide.
• ? Elmisaurus rarus, the classification of this species as Caenagnathide is controversial.

Swell

• Halszka Osmólska, Philip J. Currie, Rinchen bars Bold: Oviraptorosauria. In: David B. Weishampel, Peter Dodson and Halszka Osmólska (eds.): The Dinosauria. 2nd edition. University of California Press, Berkeley, 2004, ISBN 0-520-24209-2, pp. 165-183.