New Information On The Captorhinid Reptile Captorhinikos Chozaensis From The Lower Permian Of Texas

Event Center BC

The reptilian family Captorhinidae is the most basal member of the Eureptilia and is important to understanding the radiation and relationships of the entire clade. ‘Captorhinkos’ chozaensis is a poorly known captorhinid reptile with multiple tooth rows. The species holotype is from Foard County, North-central Texas in what was originally characterized as the Lower Permian Choza Formation of the Clear Fork Group, but is now considered the upper part of the Clear Fork Group undivided. The species holotype, specimen FMNH UR 97, is a partial lower and upper jaw with associated fragmentary tooth plates. The maxilla is fragmented, and no teeth from the anterior, single rowed region are present. However the maxilla clearly carries five rows of teeth in the multiple tooth row region, with the labial-most row extending posteriorly only about half the length of the remaining tooth rows. Contrary to the original illustration, the lower jaw exhibits clear suture lines between the dentary, coronoid, angular, surangular, and the prearticular elements. The dentary carries large but broken teeth anteriorly, and posteriorly four distinct rows of smaller teeth, the lingual-most of which extends posteriorly only about half the length of the remaining tooth rows. Preliminary reassessment of the dentition of FMNH UR 97 suggests it conforms neither to the original generic diagnosis, which specifies the lingual-most and labial-most rows of teeth on the dentary never overlap, nor more recent redefinitions of the genus Captorhinikos.