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| Bastetodon syrtos (Holroyd, 1999) Bastetodon gen. nov. Al-Ashqar, Borths, El-Desouky, Heritage, Abed, Seiffert, El-Sayed & Sallam, 2025 artwork by Ahmed Morsi |
ABSTRACT
During the Paleogene in Afro-Arabia, most terrestrial mammalian carnivores belonged to Hyaenodonta, an extinct lineage bearing a pair of carnassials between each set of molars. The Fayum Depression of Egypt preserves multiple lineages of hyaenodonts across the Eocene–Oligocene boundary. Here, we describe one of the most complete hyaenodont crania ever recovered from the lower Oligocene of the Fayum (Jebel Qatrani Formation, Quarry I, ∼30 Ma). The cranium is about the size of a hyena’s and preserves the complete upper tooth row. The long, shearing metastyle and reduced and mesially shifted protocones indicate a hypercarnivorous diet, and robust zygomatic arches suggest strong chewing muscles. Based on dental comparisons, we refer the cranium to Bastetodon syrtos (previously “Pterodon” syrtos). Bastetodon syrtos has three premolars and two molars—a reduced dental formula compared with other Fayum hyainailourines such as Akhnatenavus and European hyainailourines such as Pterodon. The cranium preserves the clover-shaped lambdoidal crest and long pharyngeal tube that unites Hyainailouroidea (Apterodontinae, Teratodontinae, and Hyainailourinae). The new Fayum cranium allows us to reevaluate the genus Pterodon and explore characters that distinguish Afro-Arabian and Eurasian species placed in this genus. Our phylogenetic analysis recovers a paraphyletic Pterodon, with B. syrtos as the sister taxon of Falcatodon schlosseri. We erect Sekhmetops to describe the large Fayum hyainailourine species S. phiomensis and S. africanus. This effort clarifies the biogeographic history of the clade that includes Pterodon, revealing multiple Tethys Seaway dispersals during the Paleogene followed by endemic radiations in Eurasia and Afro-Arabia.
Genus Bastetodon gen. nov.
Pterodon syrtos Holroyd, 1999:8, fig. 4 (original description).
Etymology—Bastetodon, from “Bastet,” one transliteration of the name of the ancient Egyptian, cat-headed goddess of protection, pleasure, and bringer of good health. She was also associated with the lion-headed goddess Sekhmet. And ancient Greek “odon” meaning tooth. Literally, “Teeth like the cat-headed goddess.”
Genus SEKHMETOPS gen. nov.
Type Species—Sekhmetops africanus (Andrews, 1904)
Included Species—Sekhmetops phiomensis (Osborn, 1909)
Etymology—From Sekhmet, the wrathful lion-headed goddess of Ancient Egypt associated with war and pestilence. And “ops” meaning “face” in ancient Greek. Literally, “Having the face of the lion-headed goddess.”
Shorouq F. Al-Ashqar, Matthew Borths, Heba El-Desouky, Steven Heritage, Mohamed Abed, Erik R. Seiffert, Sanaa El-Sayed and Hesham M. Sallam. 2025. Cranial Anatomy of the hypercarnivore Bastetodon syrtos gen. nov. (Hyaenodonta, Hyainailourinae) and A Reevaluation of Pterodon in Africa. Journal of Vertebrate Paleontology. e2442472. DOI: doi.org/10.1080/02724634.2024.2442472
Notably, this study refutes the monophyly of “Pterodon.” Based on the morphological features and the phylogenetic analyses conducted within this study, we suggest that Pterodon has never been found in Afro-Arabia. “Pterodon” syrtos is now placed in Bastetodon syrtos and “Pterodon” africanus and “Pterodon” phiomensis are placed in the new genus Sekhmetops. Under this taxonomic scheme, Pterodon is now restricted to the Eocene of Europe.
