An Upper Triassic terrestrial vertebrate assemblage from the forgotten Kocury locality (Poland) with a new aetosaur taxon

ABSTRACT

Since 1990, several localities within the Keuper (upper Middle to Upper Triassic) strata in southern Poland have yielded remains of numerous terrestrial vertebrate species. Here we report a new Upper Triassic vertebrate assemblage from the rediscovered Kocury locality. An incomplete theropod dinosaur fibula named Velocipes guerichi described in 1932 was found there. The site was then forgotten and not explored until our excavations began in 2012, that yielded material of a lungfish, a proterochersid turtle, and a new typothoracin aetosaur Kocurypelta silvestris gen. et sp. nov. The new taxon is characterized by autapomorphies of the maxilla: an elongated edentulous posterior portion longer than 80% of the posterior maxillary process, a short medial shelf restricted to the posterior portion of the bone, an anteriorly unroofed maxillary accessory cavity, and lack of a distinct groove for choanal recess on the anteromedial surface of the bone. These new finds improve our knowledge on the vertebrate diversity of the Germanic Basin in the Late Triassic, evidencing the presence of yet unrecognized taxa. Additionally, the partial cranial aetosaur material emphasizes the issues with the aetosaurian taxonomy that is focused mostly on the osteoderm morphology.

ACKNOWLEDGMENTS

We thank D. Mazurek who was the first to draw our attention to the Velocipes guerichi material, and members of the popular science website Dinozaury.com who were engaged in the preliminary study of that historical material. We thank the mayor of Kocury, D. Maleska, the forest ranger, K. Wójcik, and the forestry management of Lubliniec for their help in performance of our fieldwork. We are grateful to participants of the excavations in Kocury in seasons 2012 to 2019, including G. Niedźwiedzki and R. Piechowski. We thank G. Racki for help in obtaining the archival literature, as well as A. and U. Gaedke for helping us to translate some of these publications. We thank V. Dutra Paes-Neto for discussion and comments on a new aetosaur. We are grateful to Editor M. Young and reviewers S. Dias-da-Silva and R. T. Müller for important suggestions that improved our manuscript.

The study was financially supported by the Ministry of Science and Higher Education through the Faculty of Biology, University of Warsaw intramural grant DSM #501-D114-86-0117600-10 to Ł.C. and by the National Science Centre, Poland grants 2016/23/N/NZ8/01823 (awarded to T.Sz. —comparative studies of Triassic turtles) and 2017/27/B/NZ8/01543 (awarded to T.Su. —performing the excavation work in Kocury).