Article: Extending the footprint record of Pareiasauromorpha to the Cisuralian: earlier appearance and wider palaeobiogeography of the group

Pareiasauromorpha is one of the most important tetrapod groups of the Permian. Skeletal evidence suggests a late Kungurian origin in North America, whereas the majority of occurrences come from the Guadalupian and Lopingian of South Africa and Russia. However, Pareiasauromorpha footprints include the ichnogenus Pachypes, which is unknown from strata older than late Guadalupian. A revision of several Pachypes-like footprints from the Cisuralian–Guadalupian of Europe and North America confirm the occurrence of this ichnogenus and of the ichnospecies Pachypes ollieri comb. nov. beginning in the Artinskian. This is the earliest known occurrence of Pachypes and it coincides with the Artinskian reptile radiation. Based on a synapomorphy-based track–trackmaker correlation, P. ollieri can be attributed to nycteroleter pareiasauromorphs such as Macroleter. Therefore, the earliest occurrences of pareiasauromorph footprints precede by at least 10 myr the earliest occurrence of this group in the skeletal record. Moreover, the palaeobiogeography of the group is extended to the Cisuralian and Guadalupian of western Europe.

For access to collections/sites and other assistance during the study we warmly thank: Bernard Mourgues of the Société de Protection de la Nature Languedoc Roussillon, Stéphane Fouché of the Musée Fleury, Laurent Marivaux, Pierre-Olivier Antoine, Maeva Orliac, Monique Vianey-Liaud and Suzanne Jiquel of the Institut des Sciences de l’Évolution de Montpellier, University of Montpellier, Nour-Eddine Jalil of the Muséum National d'Histoire Naturelle, Anne Joncheray of the Musée Archéologique de Saint-Raphaël, Emmanuel Fara and Jerome Thomas of the University of Dijon, Joanne Turner and Fiona Wilson from the Dumfries Museum and Camera Obscura, Maria Rita Palombo and Linda Riti of the Palaeontological Museum of the ‘La Sapienza’ University of Rome, Robert Reisz of the University of Toronto at Mississauga and Valeriy V. Bulanov, Valeriy K. Golubev, and Yuri M. Gubin of the Paleontological Institute of Moscow. We extend our thanks to Colleen Hyde, Kim Besom and Klara Widrig, Grand Canyon National Park, for their assistance obtaining photographs of the track specimen from the Hermit Shale in the park collection. We acknowledge Sergio Llàcer, Institut Català de Paleontologia (ICP), for his assistance in the creation of several 3D photogrammetric models. We would like to thank Lara Sciscio, Massimo Bernardi, Marc J. Van den Brandt and an anonymous reviewer for useful suggestions, as well as the editors of the journal. LM was supported by the Alexander von Humboldt Foundation for his postdoc at the Urweltmuseum Geoskop of Thallichtenberg. LM is funded by the Bundesministerium für Bildung und Forschung (BMBF) for the BROMACKER project 2020. EM received funding for collection visits from: the SYNTHESYS Project (FR-TAF-3621, FR-TAF-4808; http://www.synthesys.info) which is financed by European Community Research Infrastructure Action under the FP7 ‘Capacities’ Program, Secretaria d'Universitats i de Recerca (Departament d'Economia i Coneixement, Generalitat de Catalunya; exp. num. 2013 CTP 00013) and the Erasmus+ program (2016) of the Universitat Autònoma de Barcelona. JF is supported by the Spanish Agencia Estatal de Investigación and the European Regional Development Fund of the European Union (AEI/FEDER EU, project CGL2017-82654-P). JF is member of the consolidated research group 2017 SGR 86 GRC of the Generalitat de Catalunya. We acknowledge support from the CERCA programme (ICP) from the Generalitat de Catalunya, and the project ‘Evolució dels ecosistemes durant la transició Paleozoic–Mesozoic a Catalunya’ (ref. CLT009/18/00066), financially supported by the Departament de Cultura (Generalitat de Catalunya).