New Mexico Geological Society Annual Spring Meeting — Abstracts

The New Mexico Museum of Natural History and Science (NMMNH) is unique in that for a quarter of a century it has considered vertebrate coprolites (and other trace fossils) worthy of collection during any field collecting program. Thus, coprolites ranging in age from Pennsylvanian to Pleistocene were collected in association with osteological paleofaunas and also from discrete localities rich in this type of trace fossil. As a result of this work, NMMNH has more than 600 cataloged specimens/lots of coprolites. NMMNH ‘s collection includes specimens from outside the state, but the majority are from NM. As a result, NMMNH has arguably the best sample of coprolites from any discrete area (state of NM). Other museum collections that include coprolites from NM include the American Museum of Natural History (New York), University of Michigan Museum of Paleontology (Ann Arbor) and Yale Peabody Museum of Natural History (New Haven), but their NM coprolite holdings are few in number.

The Pennsylvanian of NM includes three significant coprofaunas; (1) Kinney Brick Quarry yields non-spiralled, compressed coprolites from laminated shale; (2) Tinajas locality produces dominantly compressed, spiral coprolites from a laminated shale; and (3) Beeman coprolites from the Sacramento Mountains are not compressed and are principally spiral in morphology. Permo-Pennsylvanian and Early Permian coprolites occur in redbeds in north-central New Mexico, many of which are spiral (e.g., Hyronocopros). Upper Triassic strata (Chinle Group) across the northern half of NM yield locally abundant coprolites, particularly in Quay County, with notably large samples from Ciniza, Revuelto Creek and Apache Canyon. The Permo-Triassic ichnofaunas from NM have been significant in constructing a biostratigraphy of coprolites for this time interval. The San Juan Basin has yielded Jurassic coprolites from the Todilto Formation and a series of Late Cretaceous and Paleogene coprolites, which is currently the only stratigraphic sample that straddles the K/T boundary. Quaternary cave deposits in New Mexico yield discrete vertebrate coprolites and specimens from pack rat middens. The most significant specimens were found in association with the partially mummified carcass of the Shasta Ground Sloth (Nothrotheriops shastensis) in Doña Ana County.