A Kannemeyeriid Dicynodont from the Middle Triassic Yerrapalli Formation

Saswati Bandyopadhyay

Abstract

Wadiasaurus indicus is so far the only kannemeyeriid known for certain from India, from the early Middle Triassic Yerrapalli Formation of the Pranhita- Godavari valley. Recently, a large number of bones have been recovered from a single locality very close to the site from where the type skull of Wadiasaurus had been collected earlier. These new specimens indicate that modification of the skull characters given in previous descriptions is necessary, and also give information about the lower jaw and postcranial skeleton which confirms the familial status as earlier suggested. The parietal crest of the skull is quite specialized, forming a narrow median crest anteriorly but diverging posteriorly, half-way along its total length, to form two long rounded lobe-like bars separated by a bay. Maxillary flanges of the male members are triangular, thick and swollen, with stout cylindrical tusks; those of females are weak, laterally compressed and tuskless. A comparative study of Wadiasaurus and other kannemeyeriid genera indicates that it might have been most closely related to Kannemeyeria erithrea. A taphonomic study of the bone assemblage reveals that a herd of Wadiasaurus, including some juveniles and young animals, was trapped in the soft muds of a floodplain and buried in a small area. The herd was composed only of females, with some juvenile members. Taphonomic and osteological studies tend to indicate that the female individuals of Wadiasaurus lived in herds, whereas the solitary males joined the herds only during the mating seasons.