The genus Ptychoceras d'Orbigny in the Aptian-Albian of Patagonia and Antarctica

Abstract

Aptian - Albian Ptychoceratidae of southern Patagonia and James Ross Island, Antarctica are described. They are represented by Ptychoceras adpressum (J. SOWERBY, 1814), P. forbesianum STOLICZKA, 1865 and P. hamaimense PERVINQUIÈRE 1907. P. hamaimense occurs in the Peltocrioceras deeckei Assemblage Zone (Upper Aptian) of Patagonia and the Pictetia Assemblage Zone (Lower Albian) of Antarctica. P. adpressum has been recorded from the Upper Albian Puzosia vegaensis Assemblage Zone of Patagonia and Tetragonites Assemblage Zone of Antarctica. P. forbesianum occurs in the Middle-Late Albian of Antarctica.