New palaeontological remains from the early Permian Réalmont Basin (Tarn, France): implications for late-Variscan palaeobiogeography and Progyrolepis taxonomy (Actinopterygii)

The Réalmont Basin (Tarn, France) is a Variscan intra-mountainous basin from the Carboniferous – Permian boundary, located in the southern part of the Massif Central. The palaeofauna of this basin had been mentioned in reports but had never been described until now. This important basin provides precious insights into the southern Variscan belt faunas, which have been less studied than those of other regions of the belt.

Recent excavations at the early Permian of the Cantemerle locality have yielded vertebrate remains in the Cantemerle Formation. We describe these remains here, which include a hybodontiform fin spine of the “ Lissodus ” morphotype, several postcranial skeletons, a fragment of a maxilla, isolated teeth and numerous scales from the actinopterygian Progyrolepis cf. heyleri, and cranial remains, scapulocoracoids, fin spines, scales and postcranial body of an undetermined acanthodid.

We also describe a series of coprolites containing inclusions of Progyrolepis cf. heyleri scales. The new Progyrolepis material sheds light on the affinities of this genus, which we place apart from the acrolepids and bring closer to other Variscan macrodont actinopterygians, particularly the elonichthyids. A critical revision of the genus Progyrolepis clarifies its distribution, invalidates certain attributions, and highlights its palaeobiogeographic significance.

The ichthyofauna of the Réalmont Basin reveals a strong connection with the Bourbon-l’Archambault Basin, but also with the Bohemian basins. We also show that while the majority of Variscan aquatic taxa exhibit a high degree of endemism, this does not appear to be the case for Progyrolepis, which has a wide geographic and temporal distribution.