Elmisaurus Explained

Elmisaurus (meaning "foot sole lizard") is an extinct genus of caenagnathid dinosaur from the Late Cretaceous Nemegt Formation of Mongolia. It was a theropod belonging to the Oviraptorosauria.

Discovery

In 1970, a paleontological Polish-Mongolian expedition discovered two fragmentary specimens of a small theropod in the Ömnögovĭ province of Mongolia. The type species, Elmisaurus rarus, was named and described by Halszka Osmólska in 1981. The generic name is derived from Mongol or , "foot sole", as the type specimen consisted of a metatarsus. The specific name means "rare" in Latin. The holotype, ZPAL MgD-I/172, consists of a left metatarsus fused with the tarsalia. There are two paratypes: ZPAL MgD-I/98, consisting of a right hand and foot, and ZPAL MgD-I/20, the upper part of the left metatarsus of a larger individual.^[1]

In a 2001 study conducted by Bruce Rothschild and other paleontologists, 23 foot bones referred to Elmisaurus were examined for signs of stress fracture, but none were found.^[2]

A second species, E. elegans, was named in 1989 by Philip J. Currie.^[3] This represented a North American form originally described as a species of Ornithomimus by William Arthur Parks in 1933, based on specimen ROM 781, a foot.^[4] Currie also referred the material of the American form Caenagnathus sternbergi, based on a jaw fragment, to Elmisaurus elegans. Due to their poor preservation and geographical distance from the type species, the classification of the American forms has been contentious. In 1997, Hans-Dieter Sues stated that this supposed second species of Elmisaurus should be referred to Chirostenotes, as C. elegans,^[5] though this position was not accepted by Currie.^[6] Other researchers, including Teresa Maryańska, Halszka Osmólska, and their colleagues, followed Sues in reassigning E. elegans to Chirostenotes.^[7] In 2020, Gregory Funston assigned the material to the new genus and species Citipes.^[8]

A 2021 article by Funston and colleagues suggested Nomingia is a synonym of Elmisaurus.^[9]

Classification

The cladogram below follows an analysis by Longrich et al. in 2013, which found Elmisaurus to be a caenagnathid.^[10]

See also

• Timeline of oviraptorosaur research

Notes and References

1. Osmólska, H. (1981). Coossified tarsometatarsi in theropod dinosaurs and their bearing on the problem of bird origins. Palaeontologica Polonica 42:79-95.
2. Rothschild, B., Tanke, D. H., and Ford, T. L., 2001, Theropod stress fractures and tendon avulsions as a clue to activity: In: Mesozoic Vertebrate Life, edited by Tanke, D. H., and Carpenter, K., Indiana University Press, p. 331-336.
3. Currie, P.J. (1989). "The first records of Elmisaurus (Saurischia, Theropoda) from North America." Canadian Journal of Earth Sciences 26(6):1319-1324
4. Parks, W.A. (1933). New species of dinosaurs and turtles from the Upper Cretaceous formations of Alberta. University of Toronto Studies, Geological Series 34:1-33.
5. Sues, H.-D. (1997). "On Chirostenotes, a Late Cretaceous oviraptorosaur (Dinosauria: Theropoda) from western North America." Journal of Vertebrate Paleontology 17(4):698-716.
6. Currie, P.J., 2005, "Theropods, including birds". In: Currie, P.J. and Koppelhus E.B. (eds). Dinosaur Provincial Park, a spectacular ecosystem revealed, Part Two, Flora and Fauna from the park. Indiana University Press. pp. 367-397
7. Maryanska, Osmolska and Wolsan, (2002). "Avialan status for Oviraptorosauria." Acta Palaeontologica Polonica, 47(1): 97-116.
8. Funston. Gregory. 2020-07-27. Caenagnathids of the Dinosaur Park Formation (Campanian) of Alberta, Canada: anatomy, osteohistology, taxonomy, and evolution. Vertebrate Anatomy Morphology Palaeontology. 8. 105–153. 10.18435/vamp29362. 221067979 . 2292-1389. free.
9. Funston . Gregory F. . Currie . Philip J. . Tsogtbaatar . Chinzorig . Khishigjav . Tsogtbaatar . A partial oviraptorosaur skeleton suggests low caenagnathid diversity in the Late Cretaceous Nemegt Formation of Mongolia . PLOS ONE . 2021 . 16 . 7 . e0254564 . 10.1371/journal.pone.0254564. 34252154 . 8274908 . free .
10. Longrich . N. R. . Barnes . K. . Clark . S. . Millar . L. . Caenagnathidae from the Upper Campanian Aguja Formation of West Texas, and a Revision of the Caenagnathinae . 10.3374/014.054.0102 . Bulletin of the Peabody Museum of Natural History . 54 . 23–49 . 2013 . 128444961 .