Cathlorhynchus trismodipterus was named by Campbell et al. (2009) [Anterior of skull and mandible depressed; entrance into nasal chambers narrow and directed posterolaterally; single bone ‘‘D’’; labial cavity elongate and deep; no surface for palato-mandibular ligament; the lateral part of the prearticular forms a ridge overhanging the surangular; median septum separates the two sides of the Meckelan cavities, but fades anteriorly not meeting the dermal bones.]. Its type specimen is ANU 46495, a partial skull (Skull roof), and it is a 3D body fossil. Its type locality is Cathlorhynchus-type locality, which is in an Emsian reef, buildup or bioherm limestone in the Taemas Formation of Australia.