Support for a 'Center of Origin' in the Coral Triangle: Cryptic diversity, recent speciation, and local endemism in a diverse lineage of reef fishes (Gobiidae: Eviota)
Support for a 'Center of Origin' in the Coral Triangle: Cryptic diversity, recent speciation, and local endemism in a diverse lineage of reef fishes (Gobiidae: Eviota)
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DOI：
10.1016/j.ympev.2014.09.012
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发表时间：
2015-01-01
影响因子：
4.1
通讯作者：
Pezold, Frank
中科院分区：
文献类型：
--
作者：
Tornabene, Luke;Valdez, Samantha;Pezold, Frank
珊瑚三角被广泛认为是世界上海洋生物多样性最丰富的热点地区。有人提出解释珊瑚三角区物种丰富度上升的一个因素是该地区本身的高原位物种形成率。小虾虎鱼（虾虎鱼科：小虾虎鱼）是一种多样化的小型隐底栖珊瑚礁鱼类，其扩散能力有限，生活史和生态环境增加了物种形成的可能性。我们使用来自两个进化支的分子系统发育和生物地理数据来研究珊瑚三角区物种起源的模式、过程和时间。利用线粒体和核DNA序列数据，研究了Eviota属的分子系统发育和中间连接的单倍型网络，重点研究了E. nigriventris和E. bifasciata复合体——两个分布在珊瑚三角中心的物种群。E. nigriventris和E. bifasciata复合体都包含多种遗传上不同的、地理上受限制的颜色形态，表明最近分化的物种起源于珊瑚三角。宽松的分子钟年代估计表明，大多数物种形成事件发生在更新世，物种之间遗传断裂的地理格局与其他海洋鱼类和无根无脊椎动物的类似断裂非常吻合。海平面波动造成的区域隔离可能解释了这些物种群中的一些物种形成事件，但其他物种的形成没有物理隔离的证据。多样化事件发生的时间和珊瑚三角内依维塔属物种的现今分布表明，异域物种形成（由基因流动的短暂和/或“软”物理障碍驱动）和同域物种形成（由生态位划分和分类交配驱动）可能在珊瑚三角内的局部尺度上推动多样化。在珊瑚三角区内存在着多种年轻的、高度地方性的隐种Eviota，这表明：(1)珊瑚三角区确实是珊瑚鱼生物多样性的“摇篮”；(2)我们目前对该地区珊瑚鱼多样性的估计可能被严重低估了。(C) 2014爱思唯尔公司版权所有。
The Coral Triangle is widely regarded as the richest marine biodiversity hot-spot in the world. One factor that has been proposed to explain elevated species-richness within the Coral Triangle is a high rate of in situ speciation within the region itself. Dwarfgobies (Gobiidae: Eviota) are a diverse genus of diminutive cryptobenthic reef fishes with limited dispersal ability, and life histories and ecologies that increase potential for speciation. We use molecular phylogenetic and biogeographic data from two clades of Eviota species to examine patterns, processes and timing associated with species origination within the Coral Triangle. Sequence data from mitochondrial and nuclear DNA were used to generate molecular phylogenies and median-joining haplotype networks for the genus Eviota, with emphasis on the E. nigriventris and E. bifasciata complexes - two species groups with distributions centered in the Coral Triangle. The E. nigriventris and E. bifasciata complexes both contain multiple genetically distinct, geographically restricted color morphs indicative of recently-diverged species originating within the Coral Triangle. Relaxed molecular-clock dating estimates indicate that most speciation events occurred within the Pleistocene, and the geographic pattern of genetic breaks between species corresponds well with similar breaks in other marine fishes and sessile invertebrates. Regional isolation due to sea-level fluctuations may explain some speciation events in these species groups, yet other species formed with no evidence of physical isolation. The timing of diversification events and present day distributions of Eviota species within the Coral Triangle suggest that both allopatric speciation (driven by ephemeral and/or 'soft' physical barriers to gene flow) and sympatric speciation (driven by niche partitioning and assortative mating) may be driving diversification at local scales within the Coral Triangle. The presence of multiple young, highly-endemic cryptic species of Eviota within the Coral Triangle suggests that (i) the Coral Triangle is indeed a "cradle" of reef fish biodiversity and that (ii) our current approximations of reef fish diversity in the region may be significantly underestimated. (C) 2014 Elsevier Inc. All rights reserved.