Vertebrate tracks from the Permian of Gonfaron (Provence, Southern France) and their implications for the late Capitanian terrestrial extinction event
Résumé
The Guadalupian was a key epoch for the evolution of tetrapod faunas. It includes the earliest unambiguous occurrences of therapsids and stereospondyls (groups that later became dominant in terrestrial and freshwater environments, respectively) and the late Capitanian mass extinction event. The low-latitude faunas from this time interval, where sufficiently dated, comprise rare tetrapod body fossils whereas the most complete records are provided by ichnoassociations, especially coming from the Provence basins of France. In this paper, we revise the tetrapod ichnoassociation from the Pélitique Formation of the Le Luc Basin of Provence, identifying the following tetrapod ichnotaxa: Batrachichnus salamandroides (temnospondyls/lepospondyls), Capitosauroides talus comb. nov. (therocephalian therapsids), Dicynodontipus isp. (cynodont therapsids), Varanopus isp. (bolosaurian parareptiles), Hyloidichnus bifurcatus (captorhinomorph eureptiles) and Rhynchosauroides isp. (neodiapsid eureptiles). According to our revised ichnotaxonomy and stratigraphic correlations, we date the Pélitique Formation as late Capitanian and assign its tetrapod ichnoassociation to the newly defined Association V (Dicynodontipus sub-biochron of the Erpetopus biochron). The Pélitique Formation ichnoassociation shows a typical composition for a post-dinocephalian extinction ichnofauna, as shown by preliminary multivariate statistics on Guadalupian–Lopingian tetrapod ichnoassociations. It is similar to the contemporaneous skeletal faunas described from the mid- to high-latitude sites of Russia and South Africa and is arguably the earliest evidence of post-dinocephalian extinction recovery at low-latitudes. Our results confirm the global and abrupt impact of the late Capitanian terrestrial mass extinction and the subsequent recovery in the low-latitude realm. This extinction was probably time-equivalent with a global benthic marine mass extinction, and both events may have been linked to climatic perturbation caused by the Emeishian volcanic activity in China, which reached its peak around 260 Ma.