Using morphological and molecular tools to identify megalopae larvae collected in the field: the case of sympatric Cancer crabs
Using morphological and molecular tools to identify megalopae larvae collected in the field: the case of sympatric Cancer crabs
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使用形态学和分子工具识别现场收集的大眼幼虫：同域癌症蟹的案例
DOI：
10.1017/s0025315409003233
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发表时间：
2009
影响因子：
1.2
通讯作者：
D. Véliz
中科院分区：
文献类型：
--
作者：
L. Pardo;D. Ampuero;D. Véliz
浮游生物补充动力学的研究依赖于对每个物种的每个个体发生阶段的正确识别。这在研究幼虫阶段时尤其困难，因为幼虫阶段与同种成虫缺乏相似性，而与同一发育阶段的同种植物高度相似，因此不容易识别。东南太平洋沿岸的巨蟹属甲壳类就是这种情况。这一事实严重限制了对这些物种种群的生态学研究，这些物种构成了严重开发的当地资源。在这项研究中，我们详细地描述了现场采集的三种共域蟹类(华东方蟹、华东方蟹和冠状方蟹)的大眼幼虫。这一分析的结果是，我们能够识别出容易看到的诊断特征，从而将物种彼此区分开来。通过龟类的形状和上面有刺的存在，可以很容易地区分巨型恐龙。华氏巨蟹座有一个细长的球状贝壳，而冠状巨蟹座则有一个次方的。两种都有突出的坐骨刺，这在C.setosus中是没有的。我们通过将形态鉴定的幼虫线粒体DNA的COI基因序列与该地区发现的所有癌症种类的成虫样本的序列进行比较，证实了这些诊断特征的实用性。我们讨论了在整个地区(即相隔800公里以上的地点)发现的幼虫之间的形态差异，以及从田间获得的大眼幼虫与实验室培养的大眼目幼虫之间的形态差异。我们的结论是，同时使用形态和分子工具来鉴定十足类幼虫对于研究隐蔽物种是有用的。
Studies of recruitment dynamics in meroplanktonic organisms are dependent on the correct identification of each ontogenic stage of each species. This is particularly difficult when studying the larval stages, which are not easy to identify due to their lack of resemblance to conspecific adults and their high degree of similarity with congenerics at the same stage of development. This is the case with the crustacean megalopae of the genus Cancer along the coast of the south-eastern Pacific. This fact represents a serious limitation on ecological studies of populations of these species which constitute a heavily exploited local resource. In this study we describe in detail field collected megalopae larvae of three sympatric crab species of the genus Cancer(C. edwardsii, C. setosus and C. coronatus). As a result of this analysis we were able to identify easily visible diagnostic characters which allow the species to be distinguished from one another. The megalopae were easily distinguished by the form of the cheliped and the presence of spines on these. Cancer edwardsii has an elongated globulose cheliped, whereas C. coronatus has a subquadrate one. Both species possess a prominent ischial spine, which is absent in C. setosus. We corroborated the utility of these diagnostic characters by comparing the COI gene sequences of mitochondrial DNA of larvae identified by morphology with sequences taken from samples of the adults of all species of Cancer found in the region. We discuss the morphological variations between larvae found across the region (i.e. at sites separated by more than 800 km) and between megalopae obtained from the field versus those cultivated in the laboratory. We conclude that the simultaneous use of morphological and molecular tools for identification of decapod larvae appears useful for the study of cryptic species.