Nozaki Hisayoshi, Mahakham Wuttipong, Athibai Sujeephon, Yamamoto Kayoko, Takusagawa Mari, Misumi Osami, Herron Matthew D, Rosenzweig Frank, Kawachi Masanobu
Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.
Applied Taxonomic Research Center, Department of Biology, Faculty of Science, Khon Kaen University, Nai-Muang, Muang District, Khon Kaen 40002, Thailand.
Phycologia. 2017;56(4):469-475. doi: 10.2216/17-3.1. Epub 2017 Apr 27.
Iyengar was considered to be a phylogenetic link between and the type species Shaw because it has small somatic cells distributed from the anterior to posterior poles in 64- or 128-celled vegetative colonies. However, cultural studies and molecular and ultrastructural data are lacking in , and this species has not been recorded since 1951. Here, we performed light and electron microscopy and molecular phylogeny of based on newly established culture strains originating from Thailand. Morphological features of the present Thai species agreed well with those of the previous studies of the Indian material of and with those of the current concept of the advanced members of the Volvocaceae. The present strains exhibited homothallic sexuality; male and facultative female colonies developed within a single clonal culture. Chloroplast multigene phylogeny demonstrated that was sister to two other species of ( and Nozaki) without posterior somatic cells, and these three species of formed a robust clade, which was positioned distally in the large monophyletic group including nine taxa of sect. and (sect. ) Ehrenberg. Based on the present phylogenetic results, evolutionary losses of posterior somatic cells might have occurred in the ancestor of and . Thus, might represent an ancestral morphology of , rather than of .
因格藻被认为是[物种名称未明确]与模式种肖氏藻之间的系统发育联系，因为在64或128细胞的营养群体中，其小体细胞从前极到后极分布。然而，关于[物种名称未明确]缺乏培养研究以及分子和超微结构数据，且自1951年以来该物种就未被记录。在此，我们基于源自泰国的新建立培养菌株，对[物种名称未明确]进行了光学和电子显微镜观察以及分子系统发育分析。当前泰国物种的形态特征与之前对印度[物种名称未明确]材料的研究结果以及当前对团藻科高级成员的概念相符。当前的[物种名称未明确]菌株表现出同宗配合的有性生殖；雄性和兼性雌性群体在单一克隆培养物中发育。叶绿体多基因系统发育分析表明，[物种名称未明确]是另外两个没有后体细胞的[物种名称未明确]物种（[物种名称未明确]和野崎[物种名称未明确]）的姐妹种，这三个[物种名称未明确]物种形成了一个稳健的分支，该分支位于包括团藻属sect. [未明确分类单元名称]和[未明确分类单元名称]（sect. [未明确分类单元名称]）埃伦贝格九个分类单元的大型单系类群的远端。基于当前的系统发育结果，后体细胞的进化丧失可能发生在[物种名称未明确]和[物种名称未明确]的祖先中。因此，可以代表[物种名称未明确]而非[物种名称未明确]的祖先形态。
