New Mexico Geological Society Annual Spring Meeting — Abstracts

Recently, we described vertebrate fossils from conglomerates interbedded with marine Virgilian strata of the uppermost Wild Cow Formation at Placitas. We add to this vertebrate record the temnospondyl amphibian family Dissorophide. The best specimen is the appex of a laterally compressed neural spine, covered with sculptured dermal bone and bearing anterior and posterior articulations for dorsal dermal plates of an external series, This suite of characters is unique to certain problematic and bizarre dissorophids from the Lower Permian of Texas often reffered to the genus Aspidosaurus. The Placitas fossils represent the only New Mexican and the first Pennsylvanian evidence of a form identifiable with, or similar to, that genus.

Higher in the section, a variety of fossils occur in the upper part of the Abo Fonnation at NMMNH locality L-3922. This locality has produced bones of a pelycosaur, several plants, abundant conchostracans and isolated wings of a blattoid insect. The best blattoid specimen is the proximal two-thirds of a left tegmen. The proximal series of subcostal vein branches of the radial veins. However, the proximal branches of the radial, medial and cubital veins and the veins of the anal lobe are clear, and, though the medial seems relatively widely separated from the radial and cubital veins, the specimen indicates the family Phyloblattinidae. This cosmopolitan family occurs in North America from Desmoinesian to Wolfcampian time, and its species are useful as biostratigraphic indicators, but more and better specimens are needed from Placitas for that purpose. The conchostracans are similar to the German taxa Lioestheria monticula Martens from the Tambach Formation to L. pseudotenella Martens from the Oberhof Fonnation, both strata of Early Pennian (Wolfcampian equivalent) age.