Williams S T, Knowlton N, Weigt L A, Jara J A
Smithsonian Tropical Research Institute, Naos Marine Laboratory, USA.
Mol Phylogenet Evol. 2001 Sep;20(3):375-89. doi: 10.1006/mpev.2001.0976.
The snapping shrimp genus Alpheus is among the most diverse of caridean shrimps, and analyses of taxa separated by the Isthmus of Panama have been used to estimate rates of molecular evolution. Although seven morphological groups have been informally suggested, no formal phylogenetic analysis of the genus has been previously attempted. Here we infer the phylogenetic relationships within Alpheus using sequence data from two nuclear genes, glucose-6-phosphate isomerase and elongation factor-1alpha, and from the mitochondrial gene cytochrome oxidase I. Three major clades corresponding to previously noted morphological features were identified. Discrepancies between earlier informal morphological groupings and molecular analyses largely consisted of species whose morphologies were not entirely typical of the group to which they had been assigned. The traditional placements of shrimp with highly sessile lifestyles and consequently simplified morphologies were also not supported by molecular analyses. Phylogenies for Alpheus suggest that specialized ecological requirements (e.g., symbiotic associations and estuarine habitats) and modified claw morphologies have evolved independently several times. These new analyses also support the sister species status of transisthmian pairs analyzed previously, although very similar pairs were not always resolved with the more slowly evolving nuclear loci. In addition, six new cryptic species were identified in the course of these studies plus a seventh whose status remains to be determined.
鼓虾属（Alpheus）是藻虾科中种类最多的属之一，对被巴拿马地峡分隔的分类群进行的分析已被用于估计分子进化速率。尽管有人非正式地提出了七个形态学类群，但此前尚未对该属进行过正式的系统发育分析。在这里，我们利用来自两个核基因（葡萄糖-6-磷酸异构酶和延伸因子-1α）以及线粒体基因细胞色素氧化酶I的序列数据，推断鼓虾属内的系统发育关系。确定了与先前指出的形态特征相对应的三个主要进化枝。早期非正式形态学分组与分子分析之间的差异主要在于，一些物种的形态并不完全符合它们所属类群的典型特征。分子分析也不支持那些具有高度固着性生活方式且形态因此简化的虾类的传统分类位置。鼓虾属的系统发育表明，特殊的生态需求（如共生关系和河口栖息地）以及经过改变的爪形态已经独立进化了好几次。这些新的分析也支持了先前分析的地峡两侧成对物种的姐妹物种地位，尽管一些非常相似的成对物种在进化较慢的核基因座分析中并不总是能得到明确的结果。此外，在这些研究过程中还鉴定出了六个新的隐存物种，另有一个物种的地位仍有待确定。
