A new archosaur from the Upper Triassic Pardonet Formation of British Columbia

Abstract

Sikannisuchus huskyi, a new genus and species of archosaur, is described from the Upper Triassic (Norian) Pardonet Formation of northeastern British Columbia. It has a broad, flat skull, and may have reached 4 m in length. It is referred to the Archosauria on the basis of a lateral mandibular fenestra, laterally compressed serrated teeth, elongate transverse processes, neural spine table, osteoderms, and thecodont dentition. It is autapomorphic in that the postfrontal enters the border of both the orbit and the supratemporal fenestra, and it has a large prefrontal that contacts both the nasal and the postfrontal, excluding the frontal from the margin of the orbit. The presence of osteoderms and a well-developed clavicle exclude Sikannisuchus from the Ornithodira; however, in the absence of any preserved limb material, we cannot assign it to the Crurotarsi. Sikannisuchus is not currently referable to any known taxon of archosaur and is left as Archosauria incertae sedis.