A new Middle Triassic vertebrate assemblage from Miedary (southern Poland)

ABSTRACT

The Middle Triassic remains a poorly understood time in the evolution of land vertebrates. Here, we report a new Ladinian-age vertebrate assemblage from Miedary (southern Poland). It consists of more than 20 taxa including fish (four species of Hybodontiformes, cf. Gyrolepis, Redfieldiiformes, ‘Thelodus’, Saurichthys, Serrolepis, Prohalecites, Ptychoceratodus), amphibians (Mastodonsaurus, Gerrothorax, Plagiosternum, chroniosuchian Bystrowiella), and reptiles (Owenettidae, Blezingeria, Nothosaurus, Tanystropheus, an additional, yet unidentified tanystropheid, the doswelliid Jaxtasuchus, and another archosauromorph, as well as eight archosauriform tooth morphotypes). Preliminary comparisons suggest biogeographic and environmental similarities with roughly contemporaneous localities known from the southwestern part of the Germanic Basin. Among differences in these two areas are the presence of a new armored archosauromorph and a surprising abundance of Tanystropheus remains in the new Polish site. Miedary is currently the richest source of three-dimensionally preserved Tanystropheus material in the world, which will be crucial for a better understanding of the preferred environment and lifestyle of this highly specialized reptile.

ACKNOWLEDGMENTS

We thank M. Stachacz and G. Niedźwiedzki who were the first to examine the Miedary outcrop. We are grateful to E. Maxwell, E. Mujal, R. Schoch, and S. Spiekman (SMNS), C. Klug, T. Scheyer, and B. Scheffold (PIMUZ), H. Hagdorn (MHI), and I. Werneburg and A. Krahl (GPIT) for their hospitality and help during the visits and examination of their collections. We are grateful to editor H.-D. Sues, H. Hagdorn, two anonymous reviewers, and K. De Beats, and J. Dzik for discussion of the manuscript and for their helpful suggestions. We thank R. Motani, A. Wolniewicz, and A. Tintori for their help in identification of the vertebral centra assigned to Blezingeria. We thank K. Przestrzelska and P. Bajdek for their help in specimen preparation, and M. Dziewiński and J. Jabłoński for help in fossil transportation and photography. We express our gratitude to the authorities of the Zbrosławice municipality, as well as the mayors (W. Nawrocki, H. Kupka) and the community of the Miedary village for their long-standing hospitality. We thank K. Pielka, owner of the Miedary claypit area for support during the excavations, and S. Szczygiel for help with obtaining archival pictures of the Miedary claypit. We thank all students and volunteers taking part in the fieldwork in the Miedary site since 2015, particularly those who directly contributed to the discovery of the specimens described in the herein study: J. Armatys, M. Baranowska, M. Bieniaszewski, J. Chrostowski, M. Gierek, M. Granica, K. Grygorczyk, D. Hałubek, S. Kaczmarczyk, S. Kawecki, A. Kawińska, L. Kłosińska, A. Kowalewska, T. Kozyk, B. Kulus, A. Lewczuk, A. Lis, S. López-Torres, A. Minich, K. Nawrot, R. Nowakowski, R. Pelczar, K. Peszek, J. Rabińska, P. Rozwalak, M. Ruminowicz, M. Samborska, I. Skowron, K. Sładkiewicz, B. Surmacz, D. Szelągowski, P. Ulwański, A. Witkowski, A. Wójcicka, and S. Ziarko. The excavations and studies were supported by the National Science Centre, Poland (grants 2017/27/B/NZ8/01543, 2020/39/O/NZ8/02301 awarded to T. Su. and 2019/35/N/NZ8/03806 awarded to Ł. C.).

AUTHOR CONTRIBUTIONS

ŁC, AR, WP, MT, and TSu led excavations at the Miedary site, which resulted in the collection of the described material. WP and AR prepared the description of the geological section. ŁC and AR analyzed the numerical data. ŁC and WP prepared the figures. All authors collectively wrote and edited the manuscript.

DISCLOSURE STATEMENT

No potential conflict of interest was declared by the author(s).