Phylogenetic relationships of endemic Antarctic species of Staurotheca Allman, 1888 (Cnidaria, Hydrozoa)

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• 作者：Álvaro L. Peña Cantero ; Vicente Sentandreu
• 关键词：Staurotheca ; Hydrozoa ; Southern Ocean ; Benthos ; Phylogeny ; Character evolution
• 刊名：Polar Biology
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：40
• 期：2
• 页码：301-312
• 全文大小：
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Ecology; Oceanography; Microbiology; Plant Sciences; Zoology;
• 出版者：Springer Berlin Heidelberg
• ISSN：1432-2056
• 卷排序：40

文摘

Staurotheca is a well-characterized genus of benthic hydrozoans mostly restricted to the Antarctic ecosystem. Nineteen out of the 23 valid known species are endemic to the continental Antarctic region (High Antarctica and Scotia Ridge). The genus has proved to be monophyletic, but phylogenetic relationships among its species are practically unknown. In order to improve our understanding of the phylogenetic relationships among species of Staurotheca, and evaluate the evolution of some of their most important morphological characters, partial sequences of the mitochondrial 16S rRNA gene, mitochondrial cytochrome c oxidase subunit 3 (CO3) and nuclear calmodulin (CaM) were obtained for ten species of Staurotheca and one species of Antarctoscyphus. The most remarkable result is the discovery of two well-supported, monophyletic groups, clearly distinguishable on morphological grounds as well, that may eventually reveal as separate genera. The Staurotheca compressa clade is characterized by having female gonothecae strongly ornamented with digitiform projections and resting on a special supporting structure and by having larger microbasic mastigophores smaller than 19 µm. The second main clade has unclear relationships among its members, although there are two well-supported clades, one formed by Staurotheca pachyclada and Staurotheca polarsterni, morphologically characterized by the presence of distinct stem and the absence of both anastomoses and mushroom-shaped diaphragm, and the other consisting of Staurotheca vanhoeffeni, Staurotheca densa, Staurotheca nonscripta and Staurotheca glomulosa (the last two likely conspecific), morphologically characterized by having colonies with a closely-knit mesh appearance because of frequent branching, anastomoses and absence of main stem.