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: Decazella vetteri and Aeduella blainvillei. While the presence of the endemic D. vetteri had already been documented, we confirm the unambiguous presence of A. blainvillei 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. Decazella is found in an intermediate position within aeduellids, whereas Aeduella is found as a derived taxon close to Amelangia and Platysella. 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.

阿杜尔鱼科（Aeduellidae，辐鳍鱼纲Actinopterygii）在法国中央地块的二叠-石炭纪盆地中化石记录丰富，尤以法国阿韦龙省的德卡泽维尔盆地为典型，目前已发现2个已知物种：韦特氏德卡泽拉（Decazella vetteri）与布氏阿杜尔鱼（Aeduella blainvillei）。尽管地方性物种韦特氏德卡泽拉的存在已有文献记载，但本研究确证了此前存疑的布氏阿杜尔鱼的明确存在。自20世纪60年代这两个物种被首次正式描述以来，尚未有针对它们的分类修订研究，因此本文对二者进行了完整的重新描述。本次重描述可用于探讨阿杜尔鱼科的个体发育模式，包括部分头骨骨骼的异速生长规律以及鳞片的发育方式。此外，本研究基于一套涵盖多种二叠-石炭纪辐鳍鱼类的全新性状矩阵，开展分支系统学分析以探讨阿杜尔鱼科的系统发育关系。该分析结果显示，阿杜尔鱼科为单系科，且与伊戈尔鱼科（Igornichthyidae）构成姊妹群。德卡泽拉属在阿杜尔鱼科内处于中间演化位置，而阿杜尔鱼属则为特化类群，与阿梅朗鱼属（Amelangia）和扁体鱼属（Platysella）亲缘关系相近。本分析将北美类群置于阿杜尔鱼科的基部演化位置，这提示阿杜尔鱼科可能起源于北美，抑或是存在性状趋同演化，从而对该类群归属于阿杜尔鱼科的分类界定提出了挑战。此外，基于本次分析结果，本文还探讨了既往系统发育分析中所使用的多个性状的系统发育地位，并重新明确了它们在阿杜尔鱼科内的演化历程。