Mesadactylus

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Mesadactylus
Temporal range: Late Jurassic
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Pterosauria
Family: Anurognathidae
Genus: Mesadactylus
Jensen & Padian, 1989
Species: M. ornithosphyos
Binomial name
Mesadactylus ornithosphyos
Jensen & Padian, 1989

Mesadactylus ('mesa finger') is an extinct genus of pterosaur from the Kimmeridgian-Tithonian-age Upper Jurassic Morrison Formation of Colorado, United States. The genus was named in 1989 by James Jensen and Kevin Padian. The type species is Mesadactylus ornithosphyos.

Classification[edit]

The holotype is BYU 2024, a synsacrum of seven sacral vertebrae, featuring a unique—for a pterosaur—complete fusion of the spinae into a supraneural blade, a character, as the specific name indicates more typical for birds, at first leading Jensen to assign the fossil to a bird, Palaeopteryx.

Further referred associated remains include arms bones, pectoral girdle bones, vertebrae (including cervix and sacral), and femorae.[1] Additional material was described in 2004 (including a partial braincase)[2] and 2006; in the latter publication, the authors suggested that its larger contemporary Kepodactylus could be the same animal, although there are minor differences.[3][4]

Jensen and Padian classified Mesadactylus as a pterodactyloid. In 2007 S. Christopher Bennett claimed that the holotype and the referred material came from different forms and that, while the last was indeed of a pterodactyloid nature, the synsacrum belonged to a member of the Anurognathidae.[5]

See also[edit]

References[edit]

  1. ^ Jensen, J. A., and Padian, K. (1989) Small pterosaurs and dinosaurs from the Uncompahgre fauna (Brushy Basin Member, Morrison Formation: ?Tithonian), late Jurassic, western Colorado. Journal of Paleontology 63:363–374.
  2. ^ Smith, D.K., Sanders, R.K., and Stadtman, K.L. (2004). New material of Mesadactylus ornithosphyos, a primitive pterodactyloid pterosaur from the Upper Jurassic of Colorado. Journal of Vertebrate Paleontology 24(4):850-856.
  3. ^ King, L.R., Foster, J.R., and Scheetz, R.D. (2006). New pterosaur specimens from the Morrison Formation and a summary of the Late Jurassic pterosaur record of the Rocky Mountain region. In: Foster, J.R., and Lucas, S.G. (eds.). Paleontology and Geology of the Upper Morrison Formation. New Mexico Museum of Natural History and Science Bulletin 36:109-113. ISSN 1524-4156.
  4. ^ Harris, J.D., and Carpenter, K. (1996). A large pterodactyloid from the Morrison Formation (Late Jurassic) of Garden Park, Colorado. Neues Jahrbuch für Geologie und Paläontologie Monatshefte 1996(8):473-484.
  5. ^ Bennett, S. C. (2007). "Reassessment of Utahdactylus from the Jurassic Morrison Formation of Utah". Journal of Vertebrate Paleontology 27(1): 257–260