Complete skeleton of Eurohippus messelensis (Mammalia, Perissodactyla, Equoidea) from the early middle Eocene of Grube Messel (Germany)

Abstract

We describe the skeleton of a pregnant mare of the European equoid Eurohippus messelensis from the early middle Eocene of Grube Messel, Germany, 47.4–47.9 my of age (mammalian chronologic unit MP 11). This is the first detailed description of an individual skeleton of this species since Haupt (Abhandlungen der Hessischen Geologischen Landesanstalt, 6;1–159 Haupt 1925). Measurements prove that the skeleton of a pregnant mare fits exactly into the known variation of Eurohippus messelensis. Differences from the North American Eocene equid Arenahippus grangeri are only marginal. The size is similar, but the limb proportions indicate that cursoriality in A. grangeri had already achieved a higher level than in E. messelensis, which is 6-6.5 million years younger. We confirm the presence of rudimentary mc-I and mt-V in E. messelensis. The preservation of soft tissue is remarkable. We identified the distal end of the colon. SEM analyses display that it still contains plant material.