Re-evaluation of the enigmatic archosaur dyoplax arenaceus o. fraas, 1867 from the schilfsandstein (stuttgart formation, lower carnian, upper triassic) of stuttgart, Germany

摘要

The holotype and only specimen of the small suchian archosaur Dyoplax arenaceus O. FRaas, 1867 from the Stuttgart-Formation (Schilfsandstein) of southwestern Germany is partially redescribed and re-evaluated. The type locality can be identified as Stuttgart, not Stuttgart-Feuerbach as erroneously suggested by previous authors. A re-description of the skull and the dorsal armour provides several new characters and a restoration of the skull is attempted for the first time. The phylogenetic placement of Dyoplax is discussed. Although it is agreed with previous authors that the taxon is not an aetosaur, its placement in Crocodylomorpha is questioned. Instead we demonstrate that Dyoplax has several important cranial and postcranial features in common with Erpetosuchus from the Late Triassic of Scotland and North America, and it is tentatively re-assigned to ?Erpetosuchidae.