The Triassic ammonite Aristoptychites kolymensis (Kiparisova) from Botneheia, Spitsbergen

Abstract

Arisroplychifes kolymensis (Kiparisova) is investigated and described in detail from collections made at Botneheia, Spitsbergen, where it occurs at the top of the Botneheia Formation (Daonella Shale). It is a rather small species and the stratigraphically highest representative of the genus in Spitsbergen. Its suture line is remarkable by its possession of the additional U,-lobes between the internal lobe and the first umbilical lobe. A lobe of this kind has so far been described only once, with Arcesfes (Proarcesres) bicarinatuc by Schindewolf (1968), which suggests affinities between Ptychitidae and Arcestidae.