Nonionoides n. gen. demens (Bık, 1964), eine bisher verkannte Foraminiferenart aus dem Aquitan des Mainzer Beckens

Abstract

Investigations on the systematic position of the foraminifer generally refered to as Hastigerina demens known from the Aquitanian of the Mayence basin have shown, that a new classification has to be made. Based on the shown protoforamina the species has to be considered as belonging to the family Polystomellidae EIMER & FICKERT, 1899. The aberrant test of the species which above all appears in the evolute arrangement of the chambers, has induced the author to place the species in a new genus Nonionoides n. gen. For N. demens a benthonic way of life has to be assumed. Therefore no autochthon planctonic living foraminifers are known from the Hydrobia beds and Corbicula beds of the Mainz basin.