Meeting Abstract
The Permo-Triassic mass extinction massively reorganized terrestrial tetrapod communities from the synapsid-dominated ecosystems of the late Permian to communities with more reptile diversity in the Early-Middle Triassic. The Ruhuhu Basin of Tanzania documents the latter part of this transition; however, only large pareiasaur parareptiles and a single specimen of the ?archosauromorph Aenigmastropheus parringtoni are the known reptiles from the upper Permian Usili Formation, despite decades of collecting. We report a new, unique reptile from the Usili Formation that may represent the oldest diapsid from Tanzania. CT data reveal densely packed and well-ossified, and apparently unduplicated bones, indicating that the specimen represents the remains of an individual likely preserved within a coprolite. This small specimen (estimated humeral length = 21 mm) includes articulated forelimbs and hindlimbs with a humerus with both ent- and ectepicondylar foramina and a distinct capitellum, elongated metapodials and phalanges, and curved and tapered unguals, suggesting an arboreal lifestyle. The combination of elongated caudal vertebrae, and morphology of the pes and the manus suggest that this amniote is likely a diapsid reptile; however, a diagnostic skull was not found in this specimen. Additionally, the articulated caudal vertebrae have elongated centra distinct from those of anomodont synapsids, such as the possibly arboreal Suminia from the late Permian of Russia, indicating an arboreal ecology for some small reptiles in the late Permian.
