The San Salvador Patlanoaya section (Puebla State, Mexico) is known for its richness of many fossil groups. Among them, the calcareous shells have been principally investigated. This paper deals with Missourian-Virgilian (Late Pennsylvanian) and Leonardian (late Early Permian) Mexican fish remains. A discussion about Helicoprion and related genera, is followed by the systematic description of the revised or discovered taxa: Cooperella typicalis, Moreyella cf. M. typicalis, M. (?) sp., "Sturgeonella" quinqueloba, Hybodontidae gen. sp. 1 and 2, scale indet. Palaeobiogeographic implications are suggested. ?? 2005 Elsevier SAS. All rights reserved.