A new look at members of the superfamily Brachyopoidea (Amphibia, Temnospondyli) from the Early Triassic of Queensland and a preliminary analysis of brachyopoid relationships

Abstract

Two further finds of Keratobrachyops australis Warren (Amphibia, Temnospondyli, Chigutisauridae) from the Early Triassic Arcadia Formation of Queensland provide new information concerning skull characters not noted in the holotype. The holotype of Xenobrachyops allos Howie (Amphibia, Temnospondyli, Brachyopidae) from the same locality is redescribed following the discovery of several features not previously noted. In addition, new but fragmentary brachyopoid material from the Arcadia and overlying Glenidal Formations provides information on derived character states within the superfamily. Controversy surrounds the correct familial composition of the superfamily Brachyopoidea, with the family Brachyopidae being allied by various authors with a diversity of other Triassic and Permian families. A cladistic analysis of a number of these families has been performed in an attempt to determine interfamilial relationships. Our results support a brachyopid-chigutisaurid dichotomy within the Brachyopoidea, but also suggest the families Tupilakosauridae, Dvinosauridae and Saurerpetontidae are plesiomorphous members of the clade. Further analysis of genera within the superfamily shows that several brachyopid genera cannot be distinguished by cladistic means, indicating a need for revision of its members. Future analysis may support the erection of a new brachyopoid family for species of Sinobrachyops and Xenobrachyops.

Keywords:

• Early Triassic
• Chigutisauridae
• Brachyopidae
• Brachyopoidea
• Keratobrachyops
• apomorphy
• cladogram