Los Palaeotheriidae (Perissodactyla, Mammalia) del Eoceno de la Cuenca del Duero (Castilla y Leon, Espana)

Abstract

The systematic study of the Palaeotheriidae (Perissodactyla, Mammalia) of the Eocene of the Duero Bassin (Castilla y León, Spain) has permited to identify 3 new species: Palaeotherium giganteum nov. sp., Cantabrotherium casanovasae nov. sp. and Franzenium durense nov. sp., all of the Mazaterón bed (middle Eocene-upper Eocene, MP16-17, Almazán subbassin, Soria). Franzenium durense nov. sp. is present also in Caenes (middle Eocene, MP16, southoccidental area, Salamanca). The described forrns display a special combination of primitive characters, mainly in the premolars, with almost void molarization, and derived characters, detaching a strong hipsodonty; such combination is not known in the other species of the Family. In a biogeographical order this fauna shows a strong endemic character, with a almost complete independence of the occidental Europe and subpyrenean area, and only sorne peninsular beds, Llamaquique (Oviedo) and Huérmeces del Cerro (Guadalajara) have similar forms. In 3 other beds, situates in the southoccidental area, Casaseca de Campeán (middle Eocene, MP13-14, Zamora), Molino del Pico (upper Eocene-Oligocene, Zamora) and San Morales (Middle Eocene, MP16, Salamanca) the Palaeotheriidae are very rares and the limited material doesn't have to perrnit the identification at the generic level.