“Parrishia”的意思、由来-开放百科全书

Parrishia is an extinct genus of sphenosuchian crocodylomorph known from the Late Triassic Chinle, Dockum, and Santa Rosa Formations in Arizona and New Mexico.

Discovery and naming

The genus was named in 1995 from fossils found from the Placerias quarry of the Chinle Group in Apache County, Arizona.^[1] It was named after the paleontologist J. Michael Parrish, with the type species being P. mccreai. Parrishia was distinguished from the closely related genus Hesperosuchus on the basis of more robust vertebral centra and the lack of dorsoventrally offset articular faces of the cervical centra, thus causing the neck to be straight rather than anterodorsally curved as in Hesperosuchus.^[1]

In their description of a new crocodylomorph skeleton from the famous Whitaker quarry in Ghost Ranch, Clark et al. (2000) treated Parrishia as a nomen dubium because they considered the holotype and referred specimens undiagnostic.^[2] More complete postcranial skeletons such as PEFO 26681 have been found that clearly show that the cervical centra of Parrishia possess articular faces that are dorsoventrally offset as in Hesperosuchus.^[3] Additionally, in the holotype specimen (UCMP A269/139623) the anterior surfaces of the centa are positioned more dorsally than the posterior surfaces, giving the neck an anterodorsal curve like Hesperosuchus.^[2]^[4] Therefore, the only distinguishing character that distinguishes Parrishia from Hesperosuchus is the robustness of the vertebrae.^[3] Material from Parrishia cannot be assigned to any other known sphenosuchian genus because of the lack of postcranial apomorphies; as a result, it is considered an indeterminate genus.^[5]

In an SVP 2018 conference abstract, William Parker and colleagues reported the discovery of new specimens indicating that Parrishia represents a phytosaur and not a crocodylomorph.^[6]

References

1. ^¹{{cite journal |last=Long |first=R. A. |author2=Murry, P. A. |year=1995 |title=Late Triassic (Carnian and Norian) tetrapods from the southwestern United States |journal=New Mexico Museum of Natural History and Science Bulletin |volume=4 |pages=1–254}}
2. ^¹{{cite journal |last=Clark |first=J. M. |author2=Sues, H.-D. |author3= Berman, D. S. |year=2000 |title=A new specimen of Hesperosuchus agilis from the Upper Triassic of New Mexico and the interrelationships of basal crocodylomorph archosaurs |journal=Journal of Vertebrate Paleontology |volume=20 |issue=4 |pages=683–704 |doi=10.1671/0272-4634(2000)020[0683:ANSOHA]2.0.CO;2}}
3. ^¹{{cite book |last=Parker |first=W. G. |author2=Irmis, R. B.|year=2005 |chapter=Advances in Late Triassic vertebrate paleontology based on new material from Petrified Forest National Park, Arizona |title=Vertebrate Paleontology in Arizona |editors=Heckert, A. B. and Lucas, S. G. (eds.) |series=New Mexico Museum of Natural History and Science Bulletin |volume=29 |publisher=New Mexico Museum of Natural History and Science |location=Albuquerque, New Mexico |pages=45–58}}
4. ^{{cite journal |last=Colbert |first=E. H. |year=1952 |title=A pseudosuchian reptile from Arizona |journal=Bulletin of the American Museum of Natural History |volume=99 |pages=561–592}}
5. ^{{cite book |last=Irmis |first=R. B. |year=2005 |chapter=The vertebrate fauna of the Upper Triassic Chinle Formation in Northern Arizona |title=Guidebook to the Triassic Formations of the Colorado Plateau in Northern Arizona: Geology, Paleontology, and History |editors=Sterling J. Nesbitt, William G. Parker, and Randall B. Irmis (eds.) |publisher=Bulletin of the Mesa Southwest Museum |volume=9}}
6. ^http://vertpaleo.org/Annual-Meeting/Annual-Meeting-Home/SVP-2018-program-book-V4-FINAL-with-covers.aspx