Suckermouth armoured catfish (Loricariidae) are a highly speciose and diverse freshwater fish family, which bear upper and lower lips forming an oral disc. Its hierarchical organisation allows the attachment to various natural surfaces. The discs can possess papillae of different shapes, which are supplemented, in many taxa, by small horny projections, i.e. unculi. Although these attachment structures and their working mechanisms, which include adhesion and interlocking, are rather well investigated in some selected species, the loricariid oral disc is unfortunately understudied in the majority of species, especially with regard to comparative aspects of the diverse oral structures and their relationship to the ecology of different species. In the present paper, we investigated the papilla and unculi morphologies in 67 loricariid species, which inhabit different currents and substrates. We determined four papilla types and eight unculi types differing by forms and sizes. Ancestral state reconstructions strongly suggest convergent evolution of traits. There is no obvious correlation between habitat shifts and the evolution of specific character states. From handling the structures and from drying artefacts we could infer some information about their material properties. This, together with their shape, enabled us to carefully propose hypotheses about mechanisms of interactions of oral disc structures with natural substrates typical for respective fish species.

中文翻译：

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抱在溪流中：鲶科（鲶形目）吸盘口结构的趋同进化


吸盘鲶鱼（Loricariidae）是一种高度特异且多样化的淡水鱼科，其上唇和下唇形成口盘。它的分层组织允许附着在各种自然表面上。椎间盘可以具有不同形状的乳头，在许多类群中，这些乳头由小的角质突起（即钩）补充。尽管这些附着结构及其工作机制（包括粘附和互锁）在某些选定的物种中得到了相当好的研究，但不幸的是，在大多数物种中，对 loricariid 口腔盘的研究还不够，特别是在不同口腔结构及其它们的比较方面。与不同物种生态的关系。在本文中，我们研究了 67 种生活在不同水流和底质中的金龟子的乳头和钩的形态。我们确定了四种不同形式和大小的乳头类型和八种钩状类型。祖先状态的重建强烈表明特征的趋同进化。栖息地变化与特定性状状态的进化之间没有明显的相关性。通过处理结构和干燥文物，我们可以推断出有关其材料特性的一些信息。这与它们的形状一起，使我们能够仔细提出关于口盘结构与各鱼类典型的自然基质相互作用的机制的假设。