Re-investigation of enigmatic fish bones known as colobodontid/perleidid toothplates from the Upper Triassic Chinle Group (southwestern U.S.A.)

ASU Author/Contributor (non-ASU co-authors, if there are any, appear on document)
Andrew B. Heckert Ph.D., Assistant Professor of Geology (Creator)
Institution
Appalachian State University (ASU )
Web Site: http://www.library.appstate.edu/

Abstract: A representative selection of enigmatic denticulate/dentigerous plates from the Chinle Group previously assigned to Colobodontidae or Perleididae (“Perleidiformes”: Actinopterygii) were reinvestigated and compared to purportedly similar remains of diverse provenance and known identity. The histology of these isolated elements and fragments was also investigated to re-evaluate the former identifications and the tooth-like remains are compared to other Permo-Triassic fish groups. None of the fossils studied can be positively identified as a (crushing) toothplate of a colobodontid or a perleidid. Instead, our preliminary morpho-histologic investigation suggests that the majority of remains do not represent toothplates – despite the denticles’ striking similarity with crushing teeth. Most fragments represent denticulate dermal bone with a unique histology belonging to as-yet unidentified osteichthyans. Most purported “molariform teeth” from the Upper Triassic of the American Southwest are therefore interpreted as multiple series of dermal denticles and there is no evidence in these strata of “colobodontids” or “perleidids,” groups that were widely distributed during the Early-Middle Triassic.

Additional Information

Publication
Mutter, R.J., and Heckert, A.B., (2006) Re-investigation of enigmatic fish bones known as colobodontid/perleidid toothplates from the Upper Triassic Chinle Group (southwestern U.S.A.). New Mexico Museum of Natural History and Science Bulletin, v. 37, p. 530-542. (ISSN 1524-4156) Archived in NC DOCKS with permission of the editor. The version of record is available at: http://econtent.unm.edu/
Language: English
Date: 2006