Tseajaia

Tseajaia; Temporal range: Early Permian PreꞒ Ꞓ O S D C P T J K Pg N
	Life restoration of Tseajaia campi
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Order:	†Diadectomorpha
Family:	†Tseajaiidae; Vaughn, 1964
Genus:	†Tseajaia; Vaughn, 1964
Species:	†T. campi
Binomial name
	†Tseajaia campi; Vaughn, 1964

Tseajaia is an extinct genus of diadectomorph tetrapod from the Early Permian of western North America.^[1] The skeleton is that of a medium-sized, rather advanced reptile-like animal. In life it was about 1 metre (3 ft) long and may have looked vaguely like an iguana. The dentition was somewhat blunt, indicating herbivory or possibly omnivory. It contains a single known species, Tseajaia campi.

Discovery

The holotype of Tseajaia is a nearly complete skeleton, specimen UCMP V4225 / 59012, which is from the lowermost Organ Rock Shale or uppermost Cedar Mesa Sandstone. It was discovered by a field party led by Charles L. Camp working in San Juan County, Utah in June, 1942.^[2] The field work and the resulting discovery of Tseajaia was recorded in a 1942 article in Desert Magazine.^[3] A second specimen, UCMP V4216 / 63841, is a sequence of vertebrae from the same locality, also discovered by Camp's team.^[2] Two additional nearly complete skeletons, CM 38033 and CM 38042, were later discovered in the Cutler Formation of Rio Arriba County, New Mexico.^[4]^[5]^[6] The specimens from New Mexico were first reported in 1980,^[7] though they have yet to be fully described.^[5]

Tseajaia was named and described by Peter Paul Vaughn in 1964. The genus name comes from "Tse Ajai" ("Rock Heart"), a nearby igneous plug used as a landmark by the Navajo. The species name honors Charles L. Camp.^[2] It was subsequently redescribed by John Moss in 1972. Though the slab of rock containing the tail was lost between 1964 and 1972,^[8] though it was rediscovered by 1990.^[4]

Classification

Tseajaia was described from a single, fairly complete specimen and was given its own family, Tseajaiidae, by Vaughn (1964). It was originally thought to be a seymouriamorph.^[8] Additional finds allowing for a better taxonomic analysis indicate they belong in the Diadectomorpha, as the sister group to the large and more derived Diadectidae. Tseajaia itself being a fairly generalized form, gives a reasonable indication of the build and looks of the closest relatives of the amniotes.^[9]^[5]

References

^ Time Traveler: In Search of Dinosaurs and Other Fossils from Montana to Mongolia by Michael Novacek
^ ^a ^b ^c Vaughn, Peter Paul (1964). "Vertebrates from the Organ Rock Shale of the Cutler Group, Permian of Monument Valley and Vicinity, Utah and Arizona". Journal of Paleontology. 38 (3): 567–583. JSTOR 1301529.
^ Hilton, John (October 1942). "Thumbmark in the Book of Time" (PDF). The Desert Magazine. Vol. 5, no. 12. pp. 18–21.
^ ^a ^b Sumida, S.S. (1990). "Vertebral morphology, alternation of neural spine height, and structure in Permo-Carboniferous tetrapods, and a reappraisal of primitive modes of terrestrial locomotion". University of California Publications in Zoology. 122: 1–133.
^ ^a ^b ^c Berman, David S.; Sumida, Stuart S.; Lombard, R. Eric (1992). "Reinterpretation of the temporal and occipital regions in Diadectes and the relationships of diadectomorphs" (PDF). Journal of Paleontology. 66 (3): 481–499. doi:10.1017/S0022336000034028. ISSN 0022-3360.
^ Sumida, Stuart S.; Lombard, R. Eric; Berman, David S. (1992-05-29). "Morphology of the atlas-axis complex of the late Palaeozoic tetrapod suborders Diadectomorpha and Seymouriamorpha" (PDF). Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences. 336 (1277): 259–273. doi:10.1098/rstb.1992.0060. ISSN 0962-8436.
^ Berman, David S.; Reisz, Robert R. (24 December 1980). "A new species of Trimerorhachis (Amphibia, Temnospondyli) from the Lower Permian Abo Formation of New Mexico, with discussion of Permian faunal distributions in that state". Annals of the Carnegie Museum. 49 (24): 455–485.
^ ^a ^b Moss, John Lawrence (1972). "The morphology and phylogenetic relationships of the Lower Permian tetrapod Tseajaia campi Vaughn (Amphibia: Seymouriamorpha)". University of California Publications in Geological Science. 98: 1–72.
^ Kissel, Richard (2010). Morphology, Phylogeny, and Evolution of Diadectidae (Cotylosauria: Diadectomorpha) (PDF) (Thesis). Toronto: University of Toronto. p. 185. hdl:1807/24357.