Late Eocene snakes from the Headon Hill Formation, southern England

A number of Late Eocene, non-marine, microfaunal sites from the Headon Hill Formation in southern England have produced an unexpectedly diverse snake fauna. Well documented taxa include: Paraplatyspondylia batesi, Totlandophis thomasae, Hordleophis balconae, Palaeopython cadurcensis, Paleryx rhombifer, Caduceryx pearchi sp. nov., cf. Calamagras sp., cf. Dunnophis sp., Headonophis harrisoni, Vectophis wardi and Russellophis tenuis. Other snake taxa, reported in a preliminary way by previous authors are very doubtful elements in the fauna. These include: Eoanilius cf. E. europae, Cadurcoboa sp., cf. Bransateryx, Platyspondylia sp. and acrochordid sp. The welldocumented snake taxa reinforce the concept that southern England, in Late Eocene times, had a fauna that differed somewhat from that of southwestern France. This is based on the greater diversity of the English fauna as well as other factors; including the presence of three distinct genera of caenophidian (advanced) snakes approaching the colubrid level (modem level) of snake evolution in the Late Eocene of southern England and only one such genus in the Late Eocene of southwestern France, and the several autochthonous Late Eocene English snake taxa that are absent in the Late Eocene of southwestern France.