On the genus Crossaster (Echinodermata: Asteroidea) and its distribution
On the genus Crossaster (Echinodermata: Asteroidea) and its distribution
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DOI：
10.1371/journal.pone.0227223
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发表时间：
2020-01-07
期刊：
影响因子：
3.7
通讯作者：
Moum, Truls
中科院分区：
文献类型：
--
作者：
Ringvold, Halldis;Moum, Truls
棘皮动物门（Echinodermata）、海星总科（Asteroidea）等海星是海洋生态系统的关键物种，但其中一些物种仅用形态学标准很难识别。普通的太阳星，Crossaster papposus（Linnaeus，1767），是一个引人注目的物种，具有广泛的环北方分布。1900年，一个非常相似的物种，C. squamatus（Doderlein，1900）被描述来自东北大西洋，但是随后的作者在他们的观点上有分歧这是否是一个有效的分类群或者更确切地说是一个与温度变化相关的生态型。我们评估了来自挪威和格陵兰沃茨的标本的区别形态特征，鉴定为C。papposus和C.鳞鱼和比较它们在东北大西洋的分布推断从研究巡航。野外数据表明，C. papposus主要分布于温带和浅水沃茨，而C.有鳞鱼栖息在冰架断裂处，生活在较冷的混合水团中。利用线粒体和核DNA序列探讨了这两个假定物种的种内多样性和种间遗传分化，以及它们与全球几个十字星属同源物的系统发育关系。分子证据表明C. papposus是更多样化和地理结构的分类群，符合其广泛的分布。C. papposus和C. squamatus密切相关，但明显不同的类群，而C. papposus和C.多刺Clark，1916，后者来自南太平洋，是密切相关的，可能是姐妹分类群。
Several starfish (Echinodermata, Asteroidea) are keystone species of marine ecosystems, but some of the species are difficult to identify using morphological criteria only. The common sunstar, Crossaster papposus (Linnaeus, 1767), is a conspicuous species with a wide circumboreal distribution. In 1900, a closely similar species, C. squamatus (Doderlein, 1900) was described from the NE Atlantic Ocean, but subsequent authors have differed in their views on whether this is a valid taxon or rather an ecotype associated with temperature variations. We assessed the differentiating morphological characters of specimens from Norwegian and Greenland waters identified as C. papposus and C. squamatus and compared their distributions in the NE Atlantic as inferred from research cruises. The field data show that C. papposus is found mainly in temperate and shallow waters, whereas C. squamatus resides on the shelf-break in colder, mixed water masses. Intraspecific diversity and interspecific genetic differentiation of the two putative species, and their phylogenetic relationships to several Crossaster congeners worldwide, were explored using mitochondrial and nuclear DNA sequences. The molecular evidence suggests that C. papposus is the more diverse and geographically structured taxon, in line with its wide distribution. C. papposus and C. squamatus are closely related, yet clearly distinct taxa, while C. papposus and C. multispinus H.L. Clark, 1916, the latter from the South Pacific Ocean, are closely related, possibly sister taxa.