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.

Automated summary

Pareiasauromorpha is a significant tetrapod group in the Permian period, with its footprints dating back to the late Kungurian in North America. Through a revision of early Permian footprints in Europe and North America, the origin of the ichnogenus Pachypes and its correlation with nycteroleter pareiasauromorphs like Macroleter have been confirmed. This discovery pushes the earliest occurrences of pareiasauromorph footprints back by at least 10 million years before their skeletal records.