Abstract

SALGADO, Leonardo; PARRAS, Ana  and  GASPARINI, Zulma. A short-necked plesiosaur (Plesiosauroidea, Polycotylidae) from the Upper Cretaceous of north Patagonia. Ameghiniana [online]. 2007, vol.44, n.2, pp.349-358. ISSN 1851-8044.

Several plesiosaur vertebrae found in the Allen Formation (late Campanian-early Maastrichtian; Upper Cretaceous), at Loma Puntuda locality, Salitral de Santa Rosa, Río Negro Province, Argentina, are described. Some anatomical features, such as the amphicoelous vertebral centres higher rather than longer, a ring surrounding the posterior articular surface of the cervical vertebrae, a ventral keel in the cervical vertebrae, the cervical neural spines expanded distally and probably inclined posteriorly, and the lateral surfaces of the dorsal bodies strongly compressed, justify their assignation to the Polycotylidae, a short-necked plesiosauroid group relatively frequent in the Upper Cretaceous of North America. This is the first record of postcranial remains of a polycotylid in South America, where these plesiosaurs were known only by cranial and mandibular remains (assigned to Sulcusuchus erraini Gasparini and Spalletti) found in equivalent stratigraphic levels (Campanian-Maastrichtian), in the Chubut and Río Negro Provinces.

Keywords : Plesiosauria; Polycotylidae; Provincia de Río Negro; Campaniano-Maastrichtiano; Cretácico Superior; Plesiosauria; Polycotylidae; Río Negro Province; Campanian-Maastrichtian; Upper Cretaceous.