Regional differentiation and extensive hybridization between mitochondrial clades of the Southern Ocean giant sea spider Colossendeis megalonyx
Regional differentiation and extensive hybridization between mitochondrial clades of the Southern Ocean giant sea spider Colossendeis megalonyx
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DOI：
10.1098/rsos.140424
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发表时间：
2015-07-01
影响因子：
3.5
通讯作者：
Leese, Florian
中科院分区：
文献类型：
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作者：
Dietz, Lars;Arango, Claudia P.;Leese, Florian
评估南大洋底栖物种的巨大多样性及其演变历史是全球气候变化时代的一项中心任务。基于线粒体标记，最近有人提出，环极巨型海蜘蛛巨爪巨蛛包括一个复杂的至少6个神秘的物种，大多是小的和不重叠的分布范围。在这里，我们扩大了采样范围，包括来自南极周围的500多个线粒体COI序列标本。使用多物种划界方法，不同线粒体OTU的数量从6个增加到15-20个。与早期的研究相反，这些分支中的许多分支几乎呈环极分布。此外，对这些标本的一个子集的核内转录间隔区的分析表明，核和线粒体结果之间的不一致。这些线粒体核的不一致性表明，几个不同的线粒体谱系可以杂交，不应该被解释为神秘的物种。我们的结果表明，C。megalonyx在更新世冰期在多个避难所，其中一些可能位于南极大陆架，并强调多基因数据集的重要性，以检测神秘物种的存在，而不是他们的推理仅基于线粒体数据。
Assessing the enormous diversity of Southern Ocean benthic species and their evolutionary histories is a central task in the era of global climate change. Based on mitochondrial markers, it was recently suggested that the circumpolar giant sea spider Colossendeis megalonyx comprises a complex of at least six cryptic species with mostly small and non-overlapping distribution ranges. Here, we expand the sampling to include over 500 mitochondrial COI sequences of specimens from around the Antarctic. Using multiple species delimitation approaches, the number of distinct mitochondrial OTUs increased from six to 15-20 with our larger dataset. In contrast to earlier studies, many of these clades show almost circumpolar distributions. Additionally, analysis of the nuclear internal transcribed spacer region for a subset of these specimens showed incongruence between nuclear and mitochondrial results. These mito-nuclear discordances suggest that several of the divergent mitochondrial lineages can hybridize and should not be interpreted as cryptic species. Our results suggest survival of C. megalonyx during Pleistocene glaciations in multiple refugia, some of them probably located on the Antarctic shelf, and emphasize the importance of multi-gene datasets to detect the presence of cryptic species, rather than their inference based on mitochondrial data alone.