The anatomical study of new materials collected in the Oligocene paper shales of Chadrat (Saint-Saturnin, Puy-de-Dôme, France) allows a precise description of these cyprinodontiform fishes. The comparison with the original description of fossil fishes from the Chadrat sapropel published by Piton (1935) leads one to emphasize significant differences between this description and our own observations. Because of the lack of original figuration of the species Haplochilus piacentini, and of the loss of its holotype, the name Haplochilus piacentini should be considered as a nomen nudum. The present study has shown that the fossil fishes from Chadrat belong to a new species of the genus Francolebias Costa, 2012: F. arvernensis n. sp. Additionally, the occurrence in this locality of the skeleton of a primitive umbrid: Palaeoesox cf. weileri (Martini, 1965) is reported.
Cyprinodontiforms, Valenciidae, Umbridae, Oligocene, Central France, palaeoecology, new species.