Utahdactylus

Taxobox
name = "Utahdactylus"
fossil_range = Late Jurassic
regnum = Animalia
phylum = Chordata
classis = Sauropsida
subclassis = Diapsida
genus = "Utahdactylus"
genus_authority = Czerkas and Mickelson, 2002
binomial = "Utahdactylus kateae"
binomial_authority = Czerkas and Mickelson, 2002

"Utahdactylus" (meaning "Utah finger") was a genus of extinct reptile from the Kimmeridgian-Tithonian-age Upper Jurassic Morrison Formation of Utah, USA. Based on DM 002/CEUM 32588 (an incomplete skeleton described as including a fragment of the skull, cervical, back, and caudal vertebrae, ribs, a scapulacoracoid, and limb bones), Czerkas and Mickelson (2002) identified as a rhamphorhynchoid pterosaur. Bennett (2007) concluded that it has no diagnostic features of the pterosauria, and cannot be positively identified beyond being an indeterminate diapsid.

History

The specimen was first described by Stephen Czerkas and Debra Mickelson as a pterosaur, with a long tail and an estimated wingspan of 1.20 meters (3.94 feet). The authors considered it to be a rhamphorhynchoid, due to its long tail and large but not elongate cervical vertebrae, but without the typical groove in its forelimb bones.cite book |last=Czerkas |first=Stephen A. |coauthors=and Mickelson, Debra L. |year=2002 |chapter=The first occurrence of skeletal pterosaur remains in Utah |editor=Czerkas, Sylvia J. (ed.) |title=Feathered Dinosaurs and the Origin of Flight |publisher=The Dinosaur Museum |location=Blanding, Utah |pages=3-13 |isbn= 1-93207-501-1] It was regarded as a rhamphorhynchoid based on an unprepared specimen in the most recent review of Morrison pterosaurs.cite book |last=King |first=Lorin R. |coauthors=Foster, John R.; and Scheetz, Rodney D. |chapter=New pterosaur specimens from the Morrison Formation and a summary of the Late Jurassic pterosaur record of the Rocky Mountain region|editor=Foster, John R.; and Lucas, Spencer G. (eds.) |title=Paleontology and Geology of the Upper Morrison Formation |year=2006 |series=New Mexico Museum of Natural History and Science Bulletin, 36 |publisher=New Mexico Museum of Natural History and Science |location=Albuquerque, New Mexico |pages=149-161 ]

In 2007, pterosaur specialist Chris Bennett published a redescription wherein he disagreed with Czerkas' and Mickelson's conclusions. He found several of the bone identifications and interpretations to be mistaken, such as the skull bone (interpreted here as just a bone fragment of unknown origin), elongate tail vertebra (rib), humerus (unknown), and the orientation of the bone described as a scapulacoracoid. He could not locate other bones seen as impressions, and found no evidence to suggest that the identifiable bones came from a pterosaur. In fact, he found the quality of the bones to differ from pterosaur bones. He concluded by identifying it as Diapsida "incertae sedis", and a dubious name.cite journal |last=Bennett |first=S. Christopher |year=2007 |title=Reassessment of "Utahdactylus" from the Jurassic Morrison Formation of Utah |journal=Journal of Vertebrate Paleontology |volume=27 |issue=1 |pages=257–260 |doi=10.1671/0272-4634(2007)27 [257:ROUFTJ] 2.0.CO;2 |doilabel=10.1671/0272-4634(2007)27[257:ROUFTJ]2.0.CO;2 ]

References

External links

* [http://www.pterosaur.co.uk/species/UJP/unclass/Utadactylus.htm "Utahdactylus"] in The Pterosaur Database
* [http://archosauria.org/pterosauria/taxonomy/genera/utahdactylus.html "Utahdactylus"] in The Pterosauria