Footprints of the earliest reptiles: Notalacerta missouriensis – Ichnotaxonomy, potential trackmakers, biostratigraphy, palaeobiogeography and palaeoecology

A comprehensive revision of the earliest supposed reptile ichnotaxon, Notalacerta missouriensis, reveals that eureptiles, specifically protorothyridids like Paleothyris, are the most probable trackmakers. This study also identifies the middle Bashkirian (early Langsettian) as the earliest unequivocal occurrence of Notalacerta at the UNESCO World Heritage Site Joggins Fossil Cliffs in Nova Scotia, Canada, coinciding with the earliest known reptile body fossils (Hylonomus lyelli). The research employs a synapomorphy-based track-trackmaker attribution and revises the entire Pennsylvanian-Cisuralian record of this ichnotaxon, uncovering its unexpected abundance and wide palaeogeographical distribution. Notalacerta is predominantly found in tidal palaeoenvironments during the Bashkirian, with lesser occurrences in the Moscovian and Kasimovian, and a reappearance in fully continental environments during the Artinskian.

Marchetti, L., Voigt, S., Lucas, S., Stimson, M., King, O., & Calder, J. (2020). Footprints of the earliest reptiles: Notalacerta missouriensis – Ichnotaxonomy, potential trackmakers, biostratigraphy, palaeobiogeography and palaeoecology. Annales Societatis Geologorum Poloniae. https://doi.org/10.14241/asgp.2020.13