Caenagnathasia

Caenagnathasia ('recent jaw from Asia') is a small caenagnathid oviraptorosaurian theropod from the Late Cretaceous of Uzbekistan.

Caenagnathasia
Temporal range: Turonian, 90 Ma
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Illustration of the lower jaw
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Family: †Caenagnathidae
Subfamily: †Elmisaurinae
Genus: †Caenagnathasia
Currie et al., 1994
Species:
†C. martinsoni
Binomial name
†Caenagnathasia martinsoni
Currie et al., 1994

Discovery

The type species Caenagnathasia martinsoni was named and described in 1994 by Philip J. Currie, Stephen Godfrey and Lev Nesov. The generic name is a combination of a reference to the species' placement in the Caenagnathidae, with Asia, the continent of its provenance. The specific name honours Gerbert Genrikhovich Martinson. The genus is based on holotype N 401/12457, a pair of fused dentaries of the lower jaws. The specimen was found near Dzharakuduk in layers of the Bissekty Formation, dating to the Turonian-Coniacian, around 90 mya, making it the oldest known caenagnathoid. A second specimen was referred to the species, N 402/12457, a right dentary of a slightly smaller individual. Both individuals were adult.[1] In 2015, new material of Caenagnathasia was described. From the same site as the holotype, the material includes various vertebrae, a dentary, and a femur.[2]

Description

Caenagnathasia is the smallest known oviraptorosaur and one of the smallest non-avian dinosaurs. The jaw fragments are only a few centimetres long and total skull length has been estimated at 3 inches (7.6 cm). A 2010 estimate by Gregory S. Paul gave it a length of 2 feet (0.61 m) and a weight of 3 pounds (1.4 kg).[3] Caenagnathasia would presumably have resembled other oviraptorosaurs, which were feathered, bird-like dinosaurs with beaked skulls, long necks, and long limbs. Recent studies suggest it was one of the more primitive members of the Caenagnathidae.

Classification

Caenagnathasia was originally assigned to the Caenagnathidae. Using the definition by Hans-Dieter Sues of that clade it would even by definition be a member. It has been suggested however, that it might have a more basal position in the Oviraptorosauria, outside of the Caenagnathoidea.[4] In 2015 after the description of new material, it was found that Caenagnathasia could confidently be referred to Caenagnathidae.[2]

Life restoration

The below cladogram is based on that resolved in the description of Anzu.[5]

Caenagnathoidea
Caenagnathidae
 

Microvenator celer

 
 
 

Gigantoraptor erlianensis

 
 
 

Caenagnathasia martinsoni

 
 
 

Alberta dentary morph 3

 
 

Leptorhynchos gaddisi

 
 
 

"Caenagnathus" sternbergi

 
 
 

Anzu wyliei

 
 

Caenagnathus collinsi

 
 
 
 
 
 
 
 

Oviraptoridae

 
 

See also

References
  1. Currie, P.J.; Godfrey, S.J.; Nessov, L. (1994). "New caenagnathid (Dinosauria, Theropoda) specimens from the Upper Cretaceous of North America and Asia". Canadian Journal of Earth Sciences. 30 (10–11): 2255–2272. doi:10.1139/e93-196.
  2. Sues, H.-D.; Averianov, A. (2015). "New material of Caenagnathasia martinsoni (Dinosauria: Theropoda: Oviraptorosauria) from the Bissekty Formation (Upper Cretaceous: Turonian) of Uzbekistan". Cretaceous Research. 54: 50–59. doi:10.1016/j.cretres.2014.12.001.
  3. Paul, G.S., 2010, The Princeton Field Guide to Dinosaurs, Princeton University Press p. 152
  4. Holtz, Thomas R. Jr. (2010) Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages, Winter 2010 Appendix.
  5. Lamanna, M. C.; Sues, H. D.; Schachner, E. R.; Lyson, T. R. (2014). "A New Large-Bodied Oviraptorosaurian Theropod Dinosaur from the Latest Cretaceous of Western North America". PLoS ONE. 9 (3): e92022. doi:10.1371/journal.pone.0092022. PMC 3960162. PMID 24647078.
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