We report a hitherto unknown radiation within the clingfishes (Gobiesocidae), discovered in one of the best-studied marine biomes, the Mediterranean Sea. The monotypic genus Gouania is a Mediterranean endemic inhabiting the interstices of gravel beaches. Using geometric morphometric analyses, we identified two distinct morphotypes (characterized by a slender and a stout body shape, respectively) among Gouania willdenowi sampled from the three major Mediterranean basins (Eastern, Western and Adriatic). Slender and stout G. willdenowi occurred sympatrically in the Adriatic and the Eastern Mediterranean basins. Only the stout morphotype was found in the Western Mediterranean. Morphotypes were further distinguished by relative eye size and number of vertebrae. Based on mitochondrial and nuclear gene sequences, five highly divergent clades (COI-based K2P distances of 8 to 15%) were identified. The clades represented, respectively, stout Adriatic, slender Adriatic, stout Eastern, slender Eastern and stout Western Mediterranean Gouania. This suggests that the genus Gouania comprises at least five different species. Phylogenetic relationships among clades furthermore imply repeated evolution of convergent morphotypes. The onset of the Gouania radiation was dated to 3.23 (95% HPD 2.08-5.90) mya, and may therefore have overlapped with or followed the Messinian salinity crisis.

中文翻译：

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砾石海滩的多样化：地中海中间隙性粘鱼（Gouania，Gobiesocidae）的辐射。

我们报道了在研究最深入的海洋生物区系之一地中海中发现的扣鱼（Gobiesocidae）内迄今未知的辐射。单型属Gouania是地中海特有种，栖息在砾石海滩的缝隙中。使用几何形态计量学分析，我们从三个主要的地中海盆地（东部，西部和亚得里亚海）采样到的瓜瓦尼亚willdenowi中，确定了两种不同的形态型（分别以细长和粗壮的体形为特征）。苗条而结实的G. willdenowi发生在亚得里亚海和东地中海盆地。在地中海西部仅发现了粗壮的形态型。通过相对眼睛大小和椎骨数量进一步区分形态型。根据线粒体和核基因序列，确定了五个高度分歧的进化枝（基于COI的K2P距离为8％至15％）。进化枝分别代表粗壮的亚得里亚海，细长的亚得里亚海，粗壮的东部，细长的东部和粗壮的西地中海果阿。这表明Gouania属包含至少五个不同的物种。进化枝之间的亲缘关系还暗示收敛形态型的反复进化。Gouania辐射的发作可追溯至3.23（95％HPD 2.08-5.90）肌电，因此可能与Messinian盐度危机重叠或紧随其后。进化枝之间的亲缘关系还暗示收敛形态型的反复进化。Gouania辐射的发作可追溯至3.23（95％HPD 2.08-5.90）肌电，因此可能与Messinian盐度危机重叠或紧随其后。进化枝之间的亲缘关系还暗示收敛形态型的反复进化。Gouania辐射的发作时间可追溯到3.23（95％HPD 2.08-5.90），因此可能与Messinian盐度危机重叠或紧随其后。