Variation of Sicilian pond turtles, Emys trinacris - What makes a species cryptic?
Variation of Sicilian pond turtles, Emys trinacris - What makes a species cryptic?
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西西里池塘龟的变种，Emys trinacris - 是什么让一个物种变得神秘？
DOI：
10.1163/156853806778877095
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发表时间：
2006
影响因子：
1.6
通讯作者：
U. Fritz
中科院分区：
文献类型：
--
作者：
S. D’angelo;M. Pennisi;M. Valvo;U. Fritz
根据200余只西西里塘龟的形态资料和31个已知新标本的mtDNA序列，描述了西西里塘龟（Emys trinacris）的变异。艾米的三位一体在形态上比以前想象的更加多变。不同人群之间存在着明显的差异。成虫几乎无法与圆颈菊区分开来。然而，E. trinacris的孵化物有明显不同的模式，可以立即确定物种。此外，三角棘球绦虫的幼体似乎比圆形棘球绦虫的幼体更小、更轻。这可能与不同的繁殖策略有关。成年西西里塘龟的颜色多态性占已知环斑鳖变异的相当一部分。因此，成虫可能保留了与轮缘猿最后共同祖先的全部变异序列。我们推测，南方某些轮轮棘球蜂亚种与三爪棘球蜂的相似性，以及北方轮轮棘球蜂亚种在大小、颜色和图案上的显著差异，是北方稳定选择的结果。在北方，深色和大体型似乎是有利的，而在南方，浅色和小体型可能并不不利，这就允许了E. trinacris和南方E. orbicularis亚种的颜色多态性。此外，讨论了术语“隐种”及其在物种概念和条形码方面的含义。结论是基于mtDNA条形码的物种描述需要应用系统发育物种概念。在生物物种概念下，动物mtDNA并不总是描绘物种边界的理想工具，因为具有单系线粒体基因树的分类群既不一定是遗传上分离的，也不一定代表相同的生物物种。隐藏物种在自然界中并没有什么特别之处，因为识别它们的困难是由于人类认知能力的缺陷。“隐种”的不同生活阶段可能与类似物种有不同程度的差异，例如E. trinacris和E. o. galloitalica的幼体和成体就是这种情况。
Variation of the Sicilian pond turtle, Emys trinacris, is described, based on morphological data of more than 200 adult and immature turtles and mtDNA sequences of 31 new known-locality specimens. Emys trinacris is morphologically more variable than thought before. There exist pronounced population-specific differences. Adults are barely distinguishable from Emys orbicularis galloitalica. Hatchlings of E. trinacris are, however, significantly different patterned, allowing immediate species determination. Moreover, hatchlings of E. trinacris seem to be on average smaller and lighter than in E. orbicularis. This could be related with different reproductive strategies. Coloration polymorphism of adult Sicilian pond turtles comprises fair part of variation known in E. orbicularis. Thus, adult E. trinacris might have preserved the whole array of variation of the last common ancestor with E. orbicularis. We hypothesize that similarity of certain southern E. orbicularis subspecies and E. trinacris on one hand and pronounced differences in size, coloration and pattern of northern E. orbicularis subspecies on the other result from stabilising selection in the north. While dark coloration and large body-size seem to be beneficial in the north, light coloration and small size could be simply not disadvantageous in the south, allowing coloration polymorphisms in E. trinacris and southern E. orbicularis subspecies. Further, the term 'cryptic species' and its meaning in regard to species concepts and bar-coding is discussed. It is concluded that species delineation based on mtDNA bar- coding requires application of a Phylogenetic Species Concept. Under the Biological Species Concept, animal mtDNA is not always an ideal tool for delineating species boundaries because taxa with monophyletic mitochondrial gene trees are neither necessarily genetically isolated nor must represent the same Biological Species. Cryptic species are nothing special in nature because difficulties with their identification are due to deficits in cognitive abilities of man. This is illustrated by the fact that distinct live stages of 'cryptic species' may differ to various degrees from similar species, as is the case in hatchlings and adults of E. trinacris and E. o. galloitalica.