Lycaenops

Abstract: The gorgonopsian genus Arctops from the late Permian of South Africa is revised and redescribed. The nominal species Arctops kitchingi and Arctops watsoni are found to be junior synonyms of the type species Arctops willistoni. A well-prepared specimen previously referred to Lycaenops angusticeps and additional, previously undescribed specimens are also referred to A. willistoni. The vomerine morphology of Arctops is highly distinctive, supporting previous work highlighting the taxonomic importance of this element. Arctops is restricted to the Cistecephalus Assemblage Zone of the South African Beaufort Group. Inclusion of Arctops in a phylogenetic analysis of gorgonopsian relationships recovers it as the sister-taxon of Smilesaurus ferox, with the clade composed of Arctops + Smilesaurus positioned outside the Rubidgeinae.

Abstract: Gorgonopsia is one of the major clades of non-mammalian synapsids, and includes an array of large-bodied carnivores that were the top terrestrial predators of the late Permian. Most research on the clade has focused on these largest members; small-bodied gorgonopsians are relatively little-studied. Here, we redescribe a small gorgonopsian skull (MB.R.999) from the late Permian (Tropidostoma Assemblage Zone) of South Africa on the basis of neutron and synchrotron CT reconstructions, which yield new data on internal cranial morphology in Gorgonopsia. Because of the largely undistorted nature of MB.R.999, we were also able to reconstruct unossified areas such as the brain endocast and the otic labyrinth. MB.R.999 can be referred to the taxon Cynariops robustus based on its general skull proportions, postcanine tooth count, preparietal morphology, and vomerine morphology. We refer additional small gorgonopsian specimens from the Victoria West area to Cynariops robustus, and consider Cynarioides grimbeeki and Cynarioides laticeps to be synonymous with C. robustus. Inclusion of Cynariops in a phylogenetic analysis of Gorgonopsia recovers it within a large clade of African taxa, more closely related to Lycaenops and rubidgeines than Eriphostoma or Gorgonops.