Data from: Phylogenetic footprints of an Antarctic radiation: the Trematominae (Notothenioidei, Teleostei)

The teleost suborder Notothenioidei is restricted to the Southern Ocean and has been described as a species flock spanning the whole of it. Within the suborder, the subfamily Trematominae is important for coastal Antarctic ecosystems. The eleven Trematomus species occupy a large range of ecological niches. The genus is monophyletic if the genus Pagothenia (two additional species) and Cryothenia amphitreta, also nested within it, are included. Although the Trematominae have received much interest, the relationships among these fourteen species are still unclear. Several recent studies have tried to resolve these interrelationships; however no complete and clear picture has emerged, probably because of the use of a low number of insufficiently variable markers. The only common results places T. scotti as the sister-group of the rest of the subfamily and T. loennbergi close to T. lepidorhinus. We use here more variable markers. Four nuclear markers, two of which are new, and a mitochondrial marker for the biggest trematomine sampling ever gathered (14 species, 78 specimens). We found that several nuclear haplotypes are shared by several species (mostly in very closely related species). The haplotype patterns coupled with the cytogenetics of the subfamily suggest that a phenomenon of incomplete lineage sorting is likely to be at play. Using a calibration linked to fossil evidence, we evaluate the relative ages of each clade within the Trematominae to assess the proximity of the speciation events to one another. The main trematomine diversification was recent and sudden.

硬骨鱼纲南极鱼亚目（Notothenioidei）仅分布于南大洋，被认为是覆盖整个南大洋的适应辐射类物种群。在该亚目中，南极鱼亚科（Trematominae）对南极沿岸生态系统具有重要意义。该亚科下的11种拟南极鱼属（Trematomus）物种占据了广泛的生态位空间；若将博氏南极鱼属（Pagothenia，含2个额外物种）以及嵌套于该类群的双凹冰鱼（Cryothenia amphitreta）纳入考量，则拟南极鱼属（Trematomus）为单系群。尽管南极鱼亚科已受到广泛关注，但该亚科内14个物种的系统发育关系仍不明确。近年来多项研究试图厘清这些类群间的亲缘关系，但始终未能得到完整清晰的系统发育框架，这可能是由于所用标记数量较少且变异度不足所致。目前仅有的一致性结果显示，斯科蒂拟南极鱼（Trematomus scotti，简称T. scotti）是该亚科其余物种的姊妹群，而勒恩贝格拟南极鱼（Trematomus loennbergi，简称T. loennbergi）与鳞吻拟南极鱼（Trematomus lepidorhinus，简称T. lepidorhinus）亲缘关系较近。本研究采用了变异度更高的分子标记：4个核基因标记（其中2个为首次开发）以及1个线粒体基因标记，用于开展迄今规模最大的南极鱼亚科类群取样分析（涵盖14个物种，共78份标本）。研究发现，多个物种（多为近缘关系极强的类群）共享了部分核基因单倍型；结合该亚科的细胞遗传学特征分析单倍型分布模式，结果提示不完全谱系分选现象极有可能在该类群的演化过程中发挥了作用。本研究借助与化石证据校准的分子钟模型，估算了南极鱼亚科各演化支的相对分化时间，以探讨物种形成事件之间的时间关联性。结果显示，南极鱼亚科的主要类群分化发生时间较近且呈现快速辐射的特征。