The Berriasian genus Groebericeras in Argentina and the problem of its age

Abstract

Groebericeras bifrons Leanza is described from the Chacao Formation of central Mendoza and the Lo Valdés Formation of central Chile. The species appears limited to the Argentiniceras noduliferum Zone, which is traditionally placed in the lower Berriasian. Spanish records of Groebericeras appear to be younger (Hoedemaeker, 1982), while Groebericeras from Iraq were placed in the late Berriasian by comparison with the Spanish records (Howarth, 1992).