Approximately 250 million years ago, the Permian mass extinction killed off 90 percent of species on earth. Which vertebrates lived in the years following the Permian extinction, and what can that tell us about their recovery from this devastating event?
Researchers from the Universitat Autònoma de Barcelona and the Institut Català de Paleontologia Miquel Crusafont examined the fossilized footprints of vertebrates in the Pyrenees mountains in Catalonia from approximately 247 to 248 million years ago. They then created 3-D models and silicone molds of these delicate fossils, so that they could be preserved in scientific collections.
The researchers identified most tracks as those of archosauromorphs, the ancestors of crocodiles and dinosaurs. The majority were small, about half a meter in length, although a few specimens were longer than three meters.
The researchers also identified a new footprint, Prorotodactylus mesaxonichnus, and the new fossil evidence from the Pyrenean tracks suggests that the Pyrenean Prorotodactylus genus is related to archosauromorphs, rather than being a dinosauromorph as previously thought from other records.
The authors suggest that the abundance of archosauromorph fossils in the Pyrenees provides evidence that archosauromorphs may have played a large role in vertebrate recovery following the Permian mass extinction. Further research could explore how the archosauromorph lineage may have evolved and spread following this time period.
Image Credit: Óscar Sanisidro / Institut Català de Paleontologia Miquel Crusafont (ICP)
Reference: Mujal E, Fortuny J, Bolet A, Oms O, López JÁ (2017) An archosauromorph dominated ichnoassemblage in fluvial settings from the late Early Triassic of the Catalan Pyrenees (NE Iberian Peninsula). PLoS ONE 12(4): e0174693. doi:10.1371/journal.pone.0174693