First occurrence of the rare middle Jurassic ammonite genus Erymnocerites Jeannet from southern Poland

ABSTRACT

The genus Erymnocerites Jeannet is recorded for the first time from Poland. A single specimen, assigned to Erymnocerites argoviensis Jeannet is recorded from the Callovian Lamberti Zone from the Ogrodzieniec quarry (southern Poland). It is associated with upper Callovian forms of Peltoceras schroederi, Kosmoceras duncani and Quenstedtoceras lamberti. However, this condensed bed also yielded lowermost Oxfordian species of Peltoceratoides (Peltoceratoides) williamsoni, Peltoceratoides (Parawedekindia) arduennensis, Euaspidoceras subbabeanum, E. babeanum, Bukowskites minax, Cardioceras spp. and Hecticoceras (Putealiceras) punctatum, suggesting a condensation spanning the uppermost Callovian to lowermost Oxfordian for the lower beds at the Ogrodzieniec quarry. The recorded specimen differs from the middle Callovian Coronatum Zone E. argoviensis, which is a much larger (still septate at 188 mm), more depressed, less evolute, and has a rounded whorl section. However, based on the similarities in septal suture line and ribbing pattern, and considering the morphological variations in pachyceratids, the Polish specimen is referred to E. argoviensis. Based on the size difference between the Herznach (Switzerland) holotype of E. argoviensis (phragmocone~188 mm; maximum shell diameter~320 mm) and the Polish specimen (phragmocone 76 mm; maximum shell diameter 133 mm), it is speculated and the latter be the corresponding microconch.

KEYWORDS:

• Erymnocerites
• Callovian
• Ogrodzieniec
• Poland
• Herznach
• Switzerland

Acknowledgments

The authors thank the two reviewers, Dr Horacio Parent (Argentina) and an anonymous reviewer for their constructive comments and suggestions that greatly improved the manuscript. The authors gratefully acknowledge Mr Damian Kuźma (Katowice, Poland) for his help during field work and for photographing the Polish specimens. SJ gratefully acknowledges help from Drs. Horacio Parent (Argentina), Mikhail Rogov (Russia) and Gareth Dyke (Editor-in-Chief of Historical Biology) for their continued support. This research was supported financially by the “Fast Track Grants 2.0 Back2Mobility” (University of Silesia in Katowice, Faculty of Natural Sciences) to SJ.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work was supported by the University of Silesia in Katowice, Faculty of Natural Sciences [Fast Track Grants 2.0 Back2Mobility].