Brachyopomorpha

Brachyopomorpha is a clade of stereospondyl temnospondyls within the infraorder Trematosauria. It was constructed in 2000 to include Bothriceps australis and the superfamily Brachyopoidea.^[1] It is phylogenetically defined as a stem-based taxon including Pelorocephalus and all taxa closer to it than to Rhytidosteus. In contrast, Brachyopoidea is defined as a node-based taxon including Brachyops and Pelorocephalus and all descendants of their most recent common ancestor. Because Bothriceps is not thought to be a descendant of that recent common ancestor and would be more basal than it, the genus is placed just outside Brachyopoidea and is considered to be a sister taxon to the clade.^[1][2]

Bothriceps was once considered to be a brachyopid within Brachyopoidea, but is now placed on the brachyopoid stem closer to Brachyopoidea than to Rhytidosteidae due to the presence of several plesiomorphies (ancestral characters). The probable presence of a tabular horn in Bothriceps also suggests that it is a basal brachyopomorph rather than a brachyopid.^[1]

Keratobrachyops, once assigned to Chigutisauridae, is now thought to be a basal brachyopomorph closely related to Bothriceps.^[3]

References

1. ^ Warren, A. & Marsicano, C. (2000). "A phylogeny of the Brachyopoidea". Journal of Vertebrate Paleontology. 20 (3): 462–483. doi:10.1671/0272-4634(2000)020[0462:APOTBT2.0.CO;2]. hdl:11336/93649
2. ^ Yates, A. M. & Warren, A. A. (2000). "The phylogeny of the "higher temnospondyls" (Vertebrata, Choanata)". Zoological Journal of the Linnean Society. 128: 77–121. doi:10.1111/j.1096-3642.2000.tb00650.x
3. ^ Damiani, R. J. & Kitching, J. W. (2003). "A new brachyopid temnospondyl from the Cynognathus Assemblage Zone, Upper Beaufort Group, South Africa". Journal of Vertebrate Paleontology. 23 (1): 67–78. doi:10.1671/0272-4634(2003)23[67:ANBTFT2.0.CO;2]