Une nouvelle faune de vertébrés continentaux de l’Oligocène supérieur (MP26) à Saint-Privat-des-Vieux (Bassin d’Alès, Gard, Sud de France)

Abstract

This fauna results from the short-time excavation of a restricted fossiliferous level, following the opening of a trench for the installation of a gas conduit. Even if the amount of sediment is limited, the diversity of the fauna approaches that of other contemporaneous localities. Among the 40 vertebrate species, a few are amphibious, and most terrestrial. Among them, biochronological markers like Issiodoromys pauffiensis Vianey-Liaud, 1987 (Rodentia, Theridomyidae) are better defined. This species is compared with the type population of the MP 26 Mammalian Paleogene standardlevel (Mas-de-Pauffié, Lot; early Chattian). In addition, evolutionary grades hitherto unknown are described for several less well represented species: a sciurid rodent Comtia n. gen., a molossid bat (Cuvierimops sp.), a probable talpid, and the hyaenodontid Thereutherium thylacodes Filhol, 1876. The familial assignment of the snake Platyspondylia Rage, 1974 is discussed. The locality yielded the possible earliest shinisaurian lizard. The diversity of this new vertebrate fauna is compared to that of several localities from the same biochronological level (mainly Mas-de-Pauffié, Saint-Menoux, Saint- Henri/Saint-André, Mümliswil-Hardberg and Oensingen 11). The choice of Mas-de-pauffié as the reference-locality for MP 26 is therefore supported.