Klastomycter conodentatus, gen et sp. nov., a small early Permian parareptile with conical teeth from Richards Spur, Oklahoma

A small, pristinely preserved specimen recently collected from the Dolese Brothers limestone quarry near Richards Spur, Oklahoma provides evidence for the presence of a new early Permian parareptile at this locality. The specimen includes an articulated, nearly complete skull roof, and with the right premaxilla, right quadratojugal, most of the right palate, as well as the right epipterygoid and the sphenethmoid preserved inside. Although similar in many respects to the other contemporary parareptiles Acleistorhinus, Delorhynchus and Colobomycter, it can be distinguished from other acleistorhinids by the presence of a number of autapomorphies related to its dentition. Phylogenetic analysis places it closer to Delorhynchus and Colobomycter within Acleistorhinidae than to Acleistorhinus pteroticus. Unique aspects of the present specimen include the pronounced anterior extension of the lacrimal bone, largely homodont dentition composed of simple conical crowns with slight recurvature in the premaxillary and anterior maxillary teeth, and simple conical crowns in posterior maxillary dentition. The discovery of this new parareptile along with the surprisingly large number of acleistorhinids at Richards Spur highlights the importance of the unique fissure and vertical cave system at this site. No other early Permian site has provided such a wide diversity of parareptilian taxa, part of a complex community of terrestrial vertebrates. The present specimen highlights the fine niche partitioning that appears to have been present among reptiles of this region.