Permian tetrapod footprints from the Spanish Pyrenees

Paleozoic tetrapod footprints are a common and well-known phenomenon in almost all large European countries except for Spain. Here we report on hitherto unpublished vertebrate tracks from Permian red-beds of the south-central Pyrenees that with regard to their relative abundance, diversity and quality of preservation are suitable to fill this gap of knowledge. The described tracks come from two localities in muddy to fine-grained, sandy, alluvial plain deposits in the lower third of the Peranera Formation of the Erill-Castell Basin near Les Iglésies, northern Catalonia. The tracks can be assigned to five ichnogenera, i.e., Batrachichnus Woodworth, 1900, Limnopus Marsh, 1894, Varanopus Moodie, 1929, Hyloidichnus Gilmore, 1927, and Dromopus Marsh, 1894, that we interpret as footprints of temnospondyls, captorhinomorphs, and araeoscelids or similarly sized sauropsids with a lacertoid foot pattern. This ichnofossil assemblage is most similar to ichnofaunas from the Hermit Formation of the Grand Canyon, Arizona, the upper Abo and Robledo Mountains formations of New Mexico, and the main trace fossil site of the Tiddas Basin, Morocco, suggesting a late Early Permian (Artinskian) age for this stratigraphic level of the Peranera Formation. Considering the relative abundance and diversity of captorhinomorph footprints, the new Spanish tracefossil localities may cover the onset of the Early Permian radiation of non-diapsid eureptiles. The thick Late Paleozoic red-bed successions of the south-central Pyrenees have the potential to also bear footprints of otherwise unknown early therapsids, so systematic fossil prospecting of this area is strongly recommended.