The Arestoceratinae van Hoepen, 1942: A resurrected subfamily of late Albian brancoceratid ammonites, with description of a new genus

The subfamily Arestoceratinae van Hoepen (1942), long relegated to the synonymy of Mortoniceratinae (Wright, 1957, 1981, 1996), is resurrected for a phyletically-distinct group of strongly-compressed, generally bituberculate, late Albian brancoceratid ammonites in which there is a strong tendency for the umbilical seam to egress and the narrow subtabulate keeled venter to become fastigiate in later growth. Upper Albian biostratigraphy is discussed and a new zonation proposed with the introduction of the Goodhallites goodhalli Zone (=binum + choffati subzones) to emphasize the importance of arestoceratines to upper Albian biostratigraphy. The group is highly provincialized, and the new genus Lobitoceras is introduced for a member from the upper Albian of Angola. Sexual dimorphism is addressed, and the problem of recognizing dimorphic pairs is discussed. In addition the new genus Moutaiceras is created for a mortoniceratine from the uppermost Albian of Angola incorrectly-assigned to Arestoceras.