New Mexico Geological Society Annual Spring Meeting — Abstracts

Abstract-Here we add to the sparce record of Dimetrodon from New Mexico documenting three specimens collected from two known Lower Permian Abo Formation vertebrate fossil localities which had not previously yielded the taxon. These are diagnostic (figure-eight cross-section) neural spine fragments from the Gallina Well locality in the Joyita Hills, Socorro County and the Abo Mine locality (Scholle Copper Mine) near Abo Pass, Torrence County. The Gallina Well locality was 140 km north of the nearest Early Permian shoreline (near Las Cruces), and the Abo Mine locality was approximately 170 km north of the shoreline. These records are all of relatively small Dimetrodon, which may be better suited to fully inland and "upland" environments. Low stratigraphic positions (Virgillian-Wolfcanpian) of Dimetrodon from New Mexico indicate that diminutive size and a fully terrestrial habitat are primitive characteristics of the genus, with larger size arising as a secondary adaptation to deltaic environments.