Middle Triassic conodont assemblages from the Germanic Basin: implications for multi-element taxonomy and biogeography

Abstract

Conodonts have been a key tool for biostratigraphical, evolutionary and palaeobiogeographical studies, and the Germanic Basin has been one of the most important regions for these studies. However, few modern studies provide systematic data on the mainly endemic conodonts of the Middle Triassic Germanic Basin. Here we document conodonts from two sections in Germany, one Bithynian in age and the other late Anisian to early Ladinian in age. The two sections captured two episodes of marine fauna invasion in the Germanic epicontinental basin during the Middle Triassic. The conodont Neogondolella mombergensis, elsewhere reported as appearing globally, is reviewed and revised, confirming previous suggestions that this species only occurs in the Germanic Basin. Apparatuses of Neogondolella haslachensis and Nicoraella germanica from the Germanic Basin are proposed. It was generally expected that S and M elements within clades have a very high morphological stability compared to P elements. However, the apparatus of Nicoraella germanica differs significantly from that of south China, indicating that the morphology of S elements within a genus can be unstable, and thus promotes our understanding of conodont evolution. The rarely documented genus Gondolatus, which was suggested as representing pathological specimens, is confirmed as a valid genus in the Germanic Basin. Our data suggest that endemic conodonts evolved twice, not only in the Upper Muschelkalk Subgroup, but also in the Lower Muschelkalk Subgroup.

Keywords:

• conodonts
• multi-element apparatus
• Middle Triassic
• Germanic Basin
• palaeobiogeography

Acknowledgements

The present work was supported financially by the National Natural Science Foundation of China (NSFC 41702010, 41772002, 41425008, 41720104002 and 41621003), partly by the Program of Introducing Talents of Discipline to Universities (111 Project D17013), by the China Postdoctoral Science Foundation (2017T100766 to Y.-L. Chen), and by the Austrian National Committee (Austrian Academy of Sciences) for IGCP projects 572, 630 and NAAP0018. Frank Scholze was supported by the German Research Foundation (DFG grant number SCHN408/22-1). Siegfried Rein (Erfurt, Thuringia) is acknowledged for providing outcrop information and for his courtesy in providing Figure 1D. We thank Marissa J. Betts (University of New England, Australia) for earlier comments and suggestions. Carlos Martinez-Perez (University of Valencia) and Nicolas Goudemand (University of Lyon) are acknowledged for their reviews and constructive comments.

Additional information

Funding

The present work was supported financially by the National Natural Science Foundation of China (NSFC 41702010, 41772002, 41425008, 41720104002 and 41621003), partly by the Program of Introducing Talents of Discipline to Universities (111 Project D17013), by the China Postdoctoral Science Foundation (2017T100766 to Y.-L. Chen), and by the Austrian National Committee (Austrian Academy of Sciences) for IGCP projects 572, 630 and NAAP0018. Frank Scholze was supported by the German Research Foundation (DFG grant number SCHN408/22-1).