Dicynodont postcrania from the Triassic of Namibia and their implication for the systematics of Kannemeyeriiforme dicynodonts

Recent years have seen a renewed interest in the postcranial anatomy of Triassic dicynodonts from Africa. This study investigates the previously undescribed dicynodont postcrania from the Omingonde Formation of Namibia. Two valid dicynodont species, based upon crania, are known from this formation: Dolichuranus primaevus and Kannemeyeria lophorhinus. Dolichuranus displays a primitive generalized cranial anatomy that has made it difficult to place in Triassic dicynodont phylogeny. Some of the postcranial specimens can be positively identified as D. primaevus on the basis that they were associated with skulls of this species. Two scapula morphologies can be distinguished among the postcranial specimens that are not positively associated with diagnostic cranial remains. One of these shares similarities with the scapula of Kannemeyeria simocephalus from South Africa and is provisionally referred to K. lophorhinus. The other displays unusual characters such as the absence of an acromion and a tubercle on the lateral surface of the scapula at the level where the acromion would be expected. Inclusion of the new postcranial data in a cladistic analysis of Triassic dicynodonts resolves the position of D. primaevus as a member of Sinokannemeyeriidae. It also causes an enigmatic unnamed postcranial taxon from equivalently aged beds in South Africa to fall within the Sinokannemeyeriidae. These results highlight the importance of including postcranial data in analyses of Triassic dicynodont relationships.