A new moradisaurine captorhinid reptile (Amniota: Eureptilia) from the upper Permian of India

Abstract

Upper Permian rocks of the former supercontinent Gondwana record climax late Paleozoic terrestrial vertebrate faunas that were dominated numerically and ecologically by therapsid synapsids. Older faunal elements of earlier Paleozoic faunas, such as captorhinid reptiles, are rare and scattered components of the first amniote faunas to inhabit high-latitude regions. Here we describe a new genus and species of moradisaurine captorhinid that represents an archaic faunal element of the high-fibre herbivore fauna of the late Permian of what is now peninsular India. The presence of a relatively broad parietal and three rows of conical teeth on the maxilla and the dentary distinguishes Indosauriscus kuttyi gen. et sp. nov. from other moradisaurines. The hypodigm of I. kuttyi comprises skulls that range in length from 39 mm to 54 mm, and high ossification of the braincase elements and well developed skull-roof sutures, indicate that I. kuttyi adults were smaller than those of most moradisaurines. Results of our phylogenetic analyses suggest that moradisaurines, despite appearing first in the paleotropics, dispersed into temperate, high-latitude regions of Pangea early in their evolutionary history. Moradisaurines in dicynodont-dominated faunas, viz. Indosauriscus kuttyi and Gansurhinus naobaogouensis, were the smallest high-fibre herbivores in their respective faunas. This suggests that small body size may have evolved in these moradisaurines as they co-evolved with the more numerous and diverse dicynodont therapsids.