Madzia, D., Ekrt, B. & Sachs, S. (2026) A gem that was forgotten—Rediscovery of a rare Central European plesiosaur documented on the eve of World War II. Abstracts of the 25th Czech –Slovak–Polish Paleontological Conference: 68.
—The Early–Late Cretaceous transition marked an interval of significant restructuring in marine faunas, affecting various clades of tetrapods. The once-dominant thalattosuchians, ichthyosaurs, and pliosaurids became extinct. In turn, mosasauroids, elasmosaurids, and polycotylids diversified and flourished (Madzia and Cau, 2020). Polycotylids, in particular, experienced a burst of disparity early in the Late Cretaceous, colonizing new niches and increasing their ecological diversity. They are known from marine deposits across both the Northern and Southern Hemispheres. However, despite their growing representation in Upper Cretaceous strata, the geographic distribution and preservation of polycotylid fossils remain uneven. For example, while the polycotylid record from the West-ern Interior Basin of North America comprises rich and diverse assemblages of well-preserved specimens, remains recovered in Europe are typically scarce, often represented by isolated elements, and usually too fragmentary to be interpreted in sufficient detail, although some notable exceptions exist. Here, we report the rediscovery of a partial plesiosaur postcranial skeleton from the upper Turonian of Třebovice, Pardubice Region, Czechia. Discovered in 1932 and briefly described in January 1939 (Augusta and Soukup, 1939), it comprises parts of the cervical and dorsal series, a partial left ischium and several other girdle fragments, along with incomplete metapodials and phalanges, dorsal rib fragments, and some indeterminate elements. Although lacking most of the skeleton, the specimen clearly represents a polycotylid, likely a polycotyline. It is by far the best-preserved plesiosaur specimen from the Czech Republic and one of the best-preserved polycotylids from Europe outside Russia.
Acknowledgements: The study was funded by National Science Centre, Poland, grant no. 2023/51/B/NZ8/00899.
References Augusta, J. & Soukup, J. 1939. Kritické poznámky k Plesiosauridům z české křídy a nový nález jejich zbytků u Třebovic. Věstník královské české společnosti nauk, Třídamatematicko-přírodovědecká 6, 1–27.
Madzia, D. & Cau, A. 2020. Estimating the evolutionary rates in mosasauroids and plesiosaurs: discussion of niche occupation in Late Cretaceous seas. PeerJ 8, e8941.
