THE AMMONITE ACROCHORDICERAS IN THE TRIASSIC OF SILESIA

A new specimen of Acrochordtcems from the Pelsonian of Strzelce Opolskie, Poland, and the holotype of Stlesiucrochordtceras damest (Noetltng, 1880) are described. Ontogenetic changes in shell morphology, based on studies of museum specimens from the Gulf of Ismid, Turkey, are also presented. The pattern of temporal changes in the morphologic variability oi acrochordiceratids suggests that they many represent a single lineage, with posslble eexual dimorphism ex-pressed in a degree of involuteness of adult specimens. It is proposed to subdivide the lineage into five succesive chronospecies of a single genus. Attribution of the specimen from Strzelce Opolskie to A. tppent Arthaber, 1911 is proposed