Original paper

First record of the lytoceratid Protetragonites Hyatt, 1900 (Cephalopoda: Ammonoidea) from the Upper Jurassic of southwestern Germany

Maisch, Michael W.; Salfinger-Maisch, Angélique

Abstract

Lytoceratid ammonites are extremely rare in the Upper Jurassic of southwestern Germany and only two records have been published so far, both referred to the genus Lytoceras Suess, 1865. Here we describe a third specimen from the uppermost Impressamergel Formation (Bimammatum Zone, Late Oxfordian) of Deilingen (Baden-Württemberg). The whorl section, ornamentation and suture line indicate that it represents the first record of the genus Protetragonites Hyatt, 1900 from southwestern Germany and one of the stratigraphically oldest records of the genus. As it cannot be referred to any known species of the genus, a new species, Protetragonites zuegeli, is erected, which is characterised by its large size, slightly compressed whorls that are only in minimal contact, a rather subevolute coiling and the presence of more than ten equally spaced, straight constrictions on the phragmocone.

Keywords

stratigraphyoxfordiantaxonomylytoceratinaelytoceratidapalaeobiogeography