Priscacara

Priscacara, is a genus of extinct temperate bass^[1] described from Early to Middle Eocene fossils. It is characterized by a sunfish-like body and its stout dorsal and anal spines. The genus is best known from the Green River Formation of Wyoming, Utah and Colorado. Mass deaths of Priscacara suggest it formed schools.

Priscacara Temporal range: Eocene
Priscacara serrata
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Acanthuriformes
Family:	Moronidae
Genus:	†Priscacara Cope, 1877
Species
P. aquilonia Wilson, 1977 P. campi Hesse, 1936 P. serrata Cope, 1877

Cockerellites liops

History and classification

The type species of Priscacara is P. serrata, described from the holotype specimen, AMNH 2442.^[2] Two species are described from northwestern North America. Hesse (1936) described Priscacara campi from a single complete fossil found in the Middle Eocene Roslyn Formation of central Washington.^[3] A third species, Priscacara aquilonia was described by Wilson (1977) from the Early Eocene "Horsefly shale" of British Columbia.^[4]

A phylogenetic review of Priscacara by Whitock (2010) recognized only two species, P. serrata and P. liops.^[1]

Cockerellites liops, holotype USNM 4044^[5] had been placed in Priscacara as P. liops but is now considered a separate genus.^[6] C. liops is the most common species of Priscacara within the Green River lacustrine deposits and at certain locations it outnumbers P. serrata by over 3:1. The two species differ in the number of dorsal and anal fin rays, as well as possibly a coarser serrated rear edge of the preopercle in P. serrata. C. liops also has small conical teeth on the pharyngeal jaw, whereas P. serrata has large grinding toothplates, suggesting a diet of snails and crustaceans.^[7]

Distribution

Priscacara fossils are commonly preserved in the Fossil Lake deposits of Eocene age in westernmost Wyoming, but are rare in the coeval Lake Gossiute sediments of Wyoming and the Lake Uinta deposits of Utah and Colorado. The genus also occurs in the middle Eocene lake deposits of Washington and British Columbia.

References

1. Whitlock, J. A. (2010). "Phylogenetic relationships of the Eocene percomorph fishes Priscacara and Mioplosus". Journal of Vertebrate Paleontology. 30: 1037–1048. doi:10.1080/02724634.2010.483534. S2CID 86061795.
2. Cope, E. D. (1877). "A contribution to the knowledge of the ichthyological fauna of the Green River shales". Bulletin of the United States Geological and Geographical Survey. 3 (4): 807–819.
3. Hesse, C. (1936). "A New Species of the Genus Priscacara from the Eocene of Washington". The Journal of Geology. 44 (6): 745–750. Bibcode:1936JG.....44..745H. doi:10.1086/624475. S2CID 128981698.
4. Wilson, M. V. (1977). "Middle Eocene freshwater fishes from British Columbia". Life Sciences Contributions, Royal Ontario Museum. 113: 1–66.
5. Cope, E. D. (1884). "The vertebrata of the Tertiary formations of the West". Report of the United States Geological Survey of the Territories. 3: 1–1009.
6. Grande, L. (14 June 2013). The Lost World of Fossil Lake: Snapshots from Deep Time. University of Chicago Press; Illustrated edition. p. 169. ISBN 9780226922966.
7. Grande, L. (1984). "Paleontology of the Green River Formation, with a review of the fish fauna". Geological Survey of Wyoming Bulletin. 63: 1–333.