Acta Palaeontologica Polonica

Middle Triassic ammonoids from Silesia, Poland

Andrzej Kaim and Robert Niedźwiedzki

Acta Palaeontologica Polonica 44 (1), 1999: 93-115

A description of new ammonoid specimens (Acrochordiceras aff. damesi, cf. Acrochordiceras sp. indet., Discoptychites cf. dux, ?Paraceratites sp., cf. Balatonites sp. indet., Beneckeia buchi) from the Lower Muschelkalk (Anisian, Middle Triassic) of Silesia (southern Poland) is presented. The detailed stratigraphic position of the new finds is given. The description is supplemented with a list of all species of ammonoids found hitherto in Silesia, which was a southern part of the Germanic Basin during the Anisian. Beneckeia and Noetlingites were typical of epicontinental seas and usually appeared in the early part of transgressions. Other ammonoids entered from the Tethys into the epicontinental sea of the Germanic Basin during the maxima of transgressions. Some of them (balatonitids, paraceratitids, bulogitids, Discoptychites and probably Acrochordiceras) were successful colonizers which established their own populations in the Germanic Basin and evolved towards morphologies typical of epicontinental seas. Other (Beyrichites sp., Paraceratites binodosus, and `Trachyceras' sp.) are regarded as unsuccessful immigrants or empty shells drifted post-mortem from the Tethys.

Key words: Ammonoids, Triassic, Anisian, Muschelkalk, Silesia, Poland, Acrochordiceras, Discoptychites, Balatonites, Beneckeia, Paraceratites.

Andrzej Kaim [], Instytut Paleobiologii PAN, ul. Twarda 51/55, PL-00-818 Warszawa, Poland. Robert Niedźwiedzki [], Instytut Nauk Geologicznych, Uniwersytet Wrocławski, ul. Cybulskiego 30, PL-50-205 Wrocław, Poland.

This is an open-access article distributed under the terms of the Creative Commons Attribution License (for details please see, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.