First potential occurrence of the large aquatic snake Pterosphenus (Serpentes, Palaeophiidae) from Nigeria, with further documentation of Pterosphenus schweinfurthi from Egypt

Abstract

Abstract Pterosphenus was a genus of giant aquatic snakes distributed across North and South America, Asia and Africa. In Africa, the known occurrences of the genus are scarce, comprising isolated vertebrae and ribs from Egypt, Libya, Morocco and Angola. Here, a trunk vertebra from the middle Eocene Ameki Formation of Ameki in Nigeria is tentatively referred to Pterosphenus. For comparative purposes, multiple previously undocumented trunk vertebrae from the upper Eocene of Fayum in Egypt are also illustrated—these pertain to Pterosphenus schweinfurthi, the only named species of Pterosphenus currently recognized from Africa. The Ameki Formation vertebra is significantly smaller and likely represents an osteologically immature individual. This new find hints at a higher diversity of palaeophiids from Nigeria, which otherwise include Palaeophis africanus from the age-equivalent middle Eocene Oshosun Formation. Georgios L. Georgalis [georgalis@isez.pan.krakow.pl], Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Sławkowska 17, 31‑016 Kraków, Poland.