PROTOTAXOXYLON KRAUSEL Y DOLIANITI (TAXALES) FROM LA MATILDE FORMATION (MIDDLE JURASSIC), GRAN BAJO DE SAN JULIAN, SANTA CRUZ, ARGENTINA. Three species of Prototaxoxylon Krausel and Dolianiti are described for the first time for the Jurassic of Argentina. They are Prototaxoxylon intertrappeum Praksh and Srivastava, Prototaxoxylon uniseriale Prasad and the new species Prototaxoxylon acevedoae ... [Show full abstract] Gnaedinger and Herbst. Thus, a new group of conifers, Order Taxales, is added to the assemblage of the Jurassic "petrified woods" of Patagonia. Also, the biochron of Prototaxoxylon uniseriale is extended from the Permian to the Jurassic.