Taxonomic review, ontogeny and phylogeny of the aeduellids from the upper Carboniferous Decazeville Basin (Aveyron, France)

The Aeduellidae (Actinopterygii) are well represented in the Permo–Carboniferous basins of the French Massif Central, in particular the Decazeville Basin (Aveyron, France), with two known species: <i>Decazella vetteri</i> and <i>Aeduella blainvillei</i>. While the presence of the endemic <i>D. vetteri</i> had already been documented, we confirm the unambiguous presence of <i>A. blainvillei</i> which was previously doubtful. As no revision of these species has been proposed since their original description in the 1960s, we provide their complete redescription. This allows us to discuss the ontogeny of the aeduellids including the allometric growth of certain skull bones and the developmental pattern of scales. In addition, a cladistic analysis based on a new character matrix of several Permo–Carboniferous actinopterygians is proposed to discuss the relationships between aeduellids. This analysis recovers the Aeduellidae as a monophyletic family and as the sister group to Igornichthyidae. <i>Decazella</i> is found in an intermediate position within aeduellids, whereas <i>Aeduella</i> is found as a derived taxon close to <i>Amelangia</i> and <i>Platysella</i>. Our analysis places the North American taxa in a basal position among Aeduellidae, suggesting a possible North American origin for aeduellids, or more likely a convergence of characters that challenges their attribution to Aeduellidae. Furthermore, based on this analysis, we discuss the phylogenetic status of several characters used in previous phylogenetic analyses and redefine their evolutionary history within aeduellids.