Heteromorph ammonites from the Tata Limestone Formation (Aptian–Lower Albian), Hungary

Abstract

An important new ammonite fauna was collected by Fülöp in 1953 and 1960 from basal lenses between a Tithonian hardground and the overlying Tata Limestone Formation containing many heteromorph ammonites. This assemblage of ammonites has been determined as being of Early Albian (tardefurcata Zone) age. Among the heteromorphs are species of Tonohamites and Ptychoceras, which are familiar components of Late Aptian or Early Albian ammonite faunas. The genera Ephamulina, Hamites and Protanisoceras are also recorded, the earliest species of which had previously come from sediments of late Early Albian (mammillatum Zone) age. While Hamites and Protanisoceras are common in Europe, Ephamulina had previously only been known from Madagascar. The discovery of Ephamulina, Hamites and Protanisoceras supports the view that these phylogenetically significant ammonites had radiated close to the Aptian/Albian boundary. Four new species of Hamites (H. czaszari, H. fazekasensis, H. fueloepi and H. kalvariensis) and one new species of Tonohamites (T. boldii) are described.