Un nouveau genre de ?Palaeotheriidae (Perissodactyla, Mammalia) décelé dans les phosphorites du Quercy (Eocène supérieur ou Oligocène) d'après un arrière crâne sans dents.

Jean-Albert Remy

Cite this article: Remy J.-A., 1999. Un nouveau genre de ?Palaeotheriidae (Perissodactyla, Mammalia) décelé dans les phosphorites du Quercy (Eocène supérieur ou Oligocène) d'après un arrière crâne sans dents. Palaeovertebrata 28 (1): 75-87.

Abstract

A rear skull from the Quercy Phosphorites is described. It documents a new perissodactyl genus, likely assignable to the family Palaeotheriidae and probably paleogene of age. Owing to the lack of any tooth, this family assignment remains however somewhat hypothetical. The specimen is firstly characterised by the presence of a wide epitympanic sinus swelling and hollowing the squamosal shell and the post-glenoid process. This cavity might make up a peculiar pattern of improvement for the hearing apparatus by carrying out a kind of drum near the middle ear, whereas the bony tympanic remains barely bulged and forms but a few developed auditory bulla. This pattern appears an outcome of a trend observed with many palaeotheriids, such as Plagiolophus. Furthermore, the endocranial cast shows a rather high degree of gyrencephaly for a paleogene mammal. The prominent lambdoidal crest points out a powerful nape musculature and a lowered head bearing. Consequently, it is assumed that such an animal was probably living in somewhat open places, at the expense of rather tough vegetables. It might have been accordingly provided with a semi-hypsodont, cement covered, "plagiolophoid" dentition.