Print ISSN: 0031-0247
Online ISSN: 2274-0333
Eocene otoliths (Clinchfield Formation), Georgia
Hypoplasia: CT-scan or naked eye?
New elephant cranium from early Pliocene Ileret, Kenya
Early adaptive radiation of Theridomorpha
Evolution et extinction des reptiles marins au Mésozoïque
Relations phylétiques de Bachitherium filhol, ruminant de l'Oligocène d'Europe Occidentale.Artiodactyla; Bachitherium; Cladistic analysis; France; Mammalia; Oligocene; Ruminantia
A detailed comparative study of a complete skeleton of Bachitherium and a cladistic analysis of the sub-order Neoselenodontia lead us to propose a cladogram and a new classification of this group. The Tylopoda are the sister-group of the Ruminantia, which are chieﬂy defined by the fusion of the cuboid and navicular. Within this infra-order, Amphimeryx is the sister genus of a tetraselenodont group, in which the Hypertragulidae are well-separated group from a monophyletic group defined by the loss of trapezium, fusion of capitatum and trapezoid, and the isolation of the hypoconid on lower molars. The most primitive genera of this group, Lophiomeryx and Iberomeryx still have an open trigonid on the lower molars, but this is lingually closed in Archaeomeryx, sister-genus of the higher Ruminantia which have fused metatarsals and more evolved milk teeth. We divide them into two pan/orders : Tragulina (including the recent and miocene Tragulidae, and the North-American Leptomerycidae), and Pecora, with reduced lateral metacarpals and a new crest (telocristid) on the lower premolars. Within the Pecora, the upper molars of Gelocus are more primitive than those of Bachitherium (a genus with many autapomorphies in the dentition) itself more primitive than the group Prodremotherium + Eupecora, with fused metacarpals. We consider the Eupecora (including several genera without frontal appendages) to be monophyletic.
Published in Vol. 17, Fasc. 2 (1987)