Print ISSN: 0031-0247
Online ISSN: 2274-0333
Les traces de pas d'amphibiens, de dinosaures et autres reptiles du Mesozoïque Français
About the genus Propachynolophus Lemoine 1891
A pangolin from the French Quercy phosphorites
La palichnofaune de vertébrés tétrapodes du permien supérieur du Bassin de Lodève .
Révision des Rhombodontidae (Neoselachii Batomorphii) des bassins à phosphate du Maroc
The evolution of the molar pattern of the Erethizontidae (Rodentia,Hystricognathi) and the validity of Parasteiromys Ameghino, 1904.Argentina; Erethizontidae; Hystricognathi; Miocene; Molar evolution; Porcupines; Rodentia; systematics
The genus Parasteiromys AMEGHINO, 1904 is revalidated, and P. friantae sp. nov. (Hystricognathi, Erethizontidae) from Colhuehuapian (early Miocene) sediments of the southern cliff of Colhue-Huapi Lake (Province of Chubut, Argentina), is described. The molar morphology of these taxa and of living porcupines adds new elements to understand the dental evolution of the Erethizontidae, and to propose the hypothetical ancestral molar pattern for this family. This pattern does not correspond to any of the morphologies traditionally proposed as ancestral for South American hystricognathous rodents. The proposed pattern is characterized by a metaloph disconnected from the posteroloph and oriented towards the hypocone, and the third loph incompletely developed with the lingual portion homologous to the mesolophule of Baluchimyinae (Chapattimyidae) from the Miocene of Pakistan. The inferred steps of the molar evolution of erethizontids towards the pentalophodont condition, considered derived for the family, are illustrated. This study strengthens the hypothesis placing erethizontids in a basal position among rodents of the suborder Hystricognathi.
Published in Vol. 28, Fasc. 1 (1999)