A large Eomys antiquus (Aymard, 1853) (Mammalia, Rodentia) from the early Oligocene sedimentary deposits at Bouldnor Cliff (Isle of Wight, England, UK)

Abstract

A collection of approx. 150 isolated cheek teeth of the eomyid rodent Eomys antiquus which was obtained from a very thin layer in the Hamstead Member of the Bouldnor Formation at Bouldnor Cliff (Isle of Wight, England, UK) is described. The material is post-Grande Coupure, and earliest Oligocene in age. Comparison is made with and new data are given on teeth of Eomys from localities of a similar age situated elsewhere in Europe: Eomys antiquus from Hoogbutsel (Belgium), and Möhren 13, 19, and 20 (Germany), and Eomys aff. antiquus from Montalbán 1D (Spain), and Kocayarma (Turkish Thrace, Turkey). Teeth from Bouldnor Cliff and Hoogbutsel (Mammal Paleogene zone 21) are morphologically close to those from Möhren 13 (Mammal Paleogene zone 22), but tend to be larger. Size decrease in the course of time is also suggested by the smaller size of the teeth from Montalbán 1D (Mammal Paleogene zone 23). The morphological differences observed between the English, Belgian, and German material at the one side, and the Spanish and Turkish material at the other, confirm that the species from Montalbán 1D and Kocayarma is a different, although closely related form. The taxonomic history of Eomys antiquus is reviewed. The species is the commoner of the two oldest European Eomyidae known. General knowledge on the ecology of the eomyids suggests that at the time of deposition of the Eomys-containing layer in the Hampshire Basin forest was close by.