Evolutionary radiation of large‐bodied gorgonopsians from the lower Abrahamskraal formation of South Africa

Macungo, Zanildo; Araújo, Ricardo; Rubidge, Bruce S.; Day, Michael O.; Dollman, Kathleen N.; Benoit, Julien

Key information

Authors:

Macungo, Zanildo; Araújo, Ricardo (Ricardo Miguel Nóbrega Araújo); Rubidge, Bruce S.; Day, Michael O.; Dollman, Kathleen N.; Benoit, Julien

Published in

March 12, 2026

Abstract

<jats:title>Abstract</jats:title> <jats:p> The middle Permian represents a critical interval in therapsid evolution, when gorgonopsians emerged as some of the first specialized apex predators within terrestrial ecosystems. Despite their significance, the early diversification of Gorgonopsia in Gondwana remains poorly understood due to scarcity and fragmentary material. Here, we describe a nearly complete skull (BP/1/8260) with an occluded lower jaw from the lower Abrahamskraal Formation ( <jats:italic>Tapinocephalus</jats:italic> Assemblage Zone). The specimen exhibits a distinctive combination of cranial features, including a transversely narrow snout, small orbital and temporal openings, V‐shaped palatine bosses, and a vertically oriented occiput that distinguish it from all known gorgonopsians. Based on its unique morphology, a new taxon, <jats:italic>Jirahgorgon ceto</jats:italic> sp. nov., is established for this specimen. In our phylogenetic analysis, the new taxon forms a clade with <jats:italic>Phorcys dubei</jats:italic> , which is here named Phorcyidae fam. nov. Members of Phorcyidae are unique among basal African gorgonopsians in combining a vertical occiput and rubidgeine‐like cranial proportions, indicating that large‐bodied gorgonopsians were present in the Wordian and overturning notions that they were exclusively small carnivores until the Wuchiapingian. Basal skull length analyses indicate that body size evolution in Gorgonopsia, while largely random through time (Brownian motion evolutionary model), is nonetheless structured by shared ancestry. The discovery of <jats:italic>Jirahgorgon</jats:italic> illustrates the complexity of gorgonopsian evolution, showing an early appearance of large‐bodied, robust morphotypes and highlighting the lower Abrahamskraal Formation as a key resource for understanding the initial radiation of theriodonts. </jats:p>