PeerJ Author 105 Points Contributions by role Preprint Author 105 Contributions by subject area Ecology Evolutionary Studies Paleontology Zoology Dawid Mazurek PeerJ Author Summary Paleontology Past or current institution affiliations University of Opole PeerJ Contributions Articles 1 Preprints 2 December 15, 2023 Late Cretaceous coprolite from the Opole area (southern Poland) as evidence for a variable diet in shell-crushing shark Ptychodus (Elasmobranchii: Ptychodontidae) Dawid Mazurek, Mateusz Antczak https://doi.org/10.7717/peerj.16598 PubMed 38111662 October 5, 2017 - Version: 2 Sails at the water: ecological convergence between sphenacodontids and spinosaurids? Dawid Mazurek https://doi.org/10.7287/peerj.preprints.2917v2 March 7, 2017 - Version: 1 Halkieriid-like animals in the Late Ordovician? Dawid Mazurek https://doi.org/10.7287/peerj.preprints.2854v1