A new dicynodont genus from the Manda Formation of Tanzania (Tanganyika)

Abstract

Triassic dicynodonts hitherto described from the Manda Formation of East Africa have been ascribed to the genera Kannemeyeria and Dicynonodon. A full description of the skeleton of one species, previously called D. njalilus , is given for the first time and a new genus Tetragonias is proposed for it. This is based on the shape of the skull in dorsal view and the structure of the palate and intertemporal bar. Tetragonias is considered to be intermediate in character between the South African Lower Triassic genus Lystrosaurus and the well‐known Cynognathus‐zone genus Kannemeyeria. Two kinds of skull are known in this new genus and it is thought they are male and female. It is concluded, from a functional study of the skeleton, that Lystrosaurus could have supplied the ancestor to the later Triassic dicynodonts. The age and correlations of the Manda Formation is discussed and it is concluded that at least part of it is contemporaneous with the Cynognathus‐zone. The closest relative of Tetragonias njalilus is the Chinese dicynodont Shansiodon wangi , Yeh.