First occurrence of Psammophis (Serpentes) from Europe witnesses another Messinian herpetofaunal dispersal from Africa - biogeographic implications and a discussion of the vertebral morphology of psammophiid snakes

We here describe abundant new snake material from the late Miocene (MN 13) of Salobrena, Spain. Vertebral morphology suggests a referral of the specimens to the extant psammophiid Psammophis, documenting the first occurrence of this genus in Europe. The diversity and disparity across the vertebral morphology of different psammophiid genera are discussed. We identify vertebral features that could diagnose Psammophis and therefore enable the recognition of the genus in the fossil record. A comparison of the new Spanish form with other taxa is conducted. We provide a detailed review of the psammophiid fossil record. Material previously described from the middle Miocene of Beni Mellal, Morocco is here tentatively referred to as ?Psammophis sp., an action that renders that occurrence as the oldest (probable) record of the genus and Psammophiidae as a whole, providing thus a potential calibration point. On the other hand, Eastern European Pliocene material that had been previously supposedly referred to Psammophis is here discarded as being rather fragmentary, not affording any more precise determination. The two psammophiid genera Psammophis and Malpolon appear almost simultaneously in the European fossil record (MN 13), with the former achieving only a short-lived and apparently geographically limited distribution in the continent, while the latter still exists in its modern herpetofauna. We assess biogeographic implications of the new find, suggesting a direct dispersal event from northwestern Africa to the Iberian Peninsula during the late Miocene, facilitated by the Messinian Salinity Crisis.

Automated summary

This article describes abundant snake fossils from the late Miocene of Salobrena, Spain. The fossils are identified as the extant psammophiid genus Psammophis, marking the first occurrence of this genus in Europe. The study discusses the diversity and differences in vertebral morphology among different psammophiid genera, and identifies vertebral features that can be used to diagnose Psammophis in the fossil record.