Crandall Eric D, Frey Melissa A, Grosberg Richard K, Barber Paul H
Boston University Marine Program, Department of Biology, 5 Cummington Street, Boston, MA 02215, USA.
Mol Ecol. 2008 Jan;17(2):611-26. doi: 10.1111/j.1365-294X.2007.03600.x. Epub 2007 Dec 20.
Marine species with ranges that span the Indo-Australian Archipelago (IAA) exhibit a range of phylogeographical patterns, most of which are interpreted in the context of vicariance between Indian and Pacific Ocean populations during Pliocene and Pleistocene low sea-level stands. However, patterns often vary among ecologically similar taxa, sometimes even within genera. This study compares phylogeographical patterns in two species of highly dispersive neritid gastropod, Nerita albicilla and Nerita plicata, with nearly sympatric ranges that span the Indo-Pacific. Mitochondrial COI sequences from >1000 individuals from 97 sites reveal similar phylogenies in both species (two divergent clades differing by 3.2% and 2.3%, for N. albicilla and N. plicata, respectively). However, despite ecological similarity and congeneric status, the two species exhibit phylogeographical discordance. N. albicilla has maintained reciprocal monophyly of Indian and Pacific Ocean populations, while N. plicata is panmictic between oceans, but displays a genetic cline in the Central Pacific. Although this difference might be explained by qualitatively different demographic histories, parameter estimates from three coalescent models indicate that both species have high levels of gene flow between demes (2Nem>75), and share a common history of population expansion that is likely associated with cyclical flooding of continental shelves and island lagoons following low sea-level stands. Results indicate that ecologically similar, codistributed species may respond very differently to shared environmental processes, suggesting that relatively minor differences in traits such as pelagic larval duration or microhabitat association may profoundly impact phylogeographical structure.
分布范围跨越印度 - 澳大利亚群岛（IAA）的海洋物种呈现出一系列系统地理学模式，其中大部分是根据上新世和更新世海平面较低时期印度洋和太平洋种群之间的隔离来解释的。然而，这些模式在生态相似的分类群中往往有所不同，有时甚至在属内也存在差异。本研究比较了两种具有高度扩散性的蜒螺科腹足纲动物——白纹蜒螺（Nerita albicilla）和褶蜒螺（Nerita plicata）的系统地理学模式，它们的分布范围几乎同域，横跨印度 - 太平洋地区。来自97个地点的1000多个个体的线粒体细胞色素氧化酶亚基I（COI）序列显示，这两个物种具有相似的系统发育关系（白纹蜒螺和褶蜒螺分别有两个不同的分支，差异分别为3.2%和2.3%）。然而，尽管这两个物种在生态上相似且同属，但它们表现出系统地理学上的不一致。白纹蜒螺保持了印度洋和太平洋种群的相互单系性，而褶蜒螺在两个大洋之间是随机交配的，但在中太平洋呈现出遗传渐变群。虽然这种差异可能可以用定性不同的种群历史来解释，但来自三个溯祖模型的参数估计表明，这两个物种在种群间都有高水平的基因流（2Nem>75），并且共享一个可能与海平面较低时期后大陆架和岛屿泻湖的周期性洪水相关的种群扩张共同历史。结果表明，生态相似、分布范围重叠的物种对共同的环境过程可能有非常不同的反应，这表明诸如浮游幼虫持续时间或微生境关联等特征上相对较小的差异可能会深刻影响系统地理学结构。
