Morphology, life history, and molecular phylogeny of Stschapovia flagellaris (Tilopteridales, Phaeophyceae) and the erection of the Stschapoviaceae fam. nov.
Morphology, life history, and molecular phylogeny of Stschapovia flagellaris (Tilopteridales, Phaeophyceae) and the erection of the Stschapoviaceae fam. nov.
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DOI：
10.1111/j.1529-8817.2004.03153.x
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发表时间：
2004-12-01
影响因子：
2.9
通讯作者：
Sasaki, H
中科院分区：
文献类型：
--
作者：
Kawai, H;Sasaki, H
利用rbcL和rDNA（5.8S、internal transscribed spacer 2和部分26S）基因序列，对西北太平洋特有的鞭毛虫Stschapovia flagellaris的物候、生活史、生殖结构的超微结构和分子遗传学进行了研究。本种最初被分类为Delamareales与Delamarea，Coelocladia和Cladothele一起。然而，这三个属后来被转移到Dictyosiphonales，而Stschapovia的系统位置仍然不清楚。在日本北海道网走，该种通过从多年生甲壳固着物形成新的直立叶状体或通过从直立叶状体释放的卵的孤雌生殖发育而再生。没有世代交替。在冬季，雌雄同株的直立叶状体在其加厚部分形成生殖结构（即多室精子器和卵原细胞）。精子有一个带有眼斑的叶绿体和一个长的前鞭毛和短的后鞭毛。卵含有许多盘状的叶绿体、囊泡和液泡。既没有观察到卵子对假定精子的性吸引，也没有观察到它们的性融合。分子系统发育分析表明，该属与盐管藻科亲缘关系最近，与叶下蕨科和毛蕨科（Tilopteridales s.）s.）。Stschapovia和Tilopteridaceae有几个重要的形态相似性：叶绿体缺乏蛋白核，缺乏有性生殖，尽管释放明显的精子，雌雄同株配子体的发生，和直立叶状体的早期发育模式的相似性。总之，我们建议建立一个新的家庭Stschapoviaceae容纳Stschapovia和放置在该家庭的顺序Tilopteridales与Tilopteridaceae，Halosiphonaceae，Phyllariaceae。
The phenology, life history, ultrastructure of reproductive structures, and molecular phylogeny using rbcL and rDNA (5.8S, internal transcribed spacer 2, and partial 26S) gene sequences of Stschapovia flagellaris, endemic to the northwestern Pacific Ocean, were studied. This species was first classified in the order Delamareales together with Delamarea, Coelocladia, and Cladothele. Those three genera, however, were later transferred to Dictyosiphonales, whereas the systematic position of Stschapovia remained unclear. At Abashiri, Hokkaido, Japan, the species regenerated by forming a new erect thallus from a perennial crustose holdfast or by presumably parthenogenetic development of eggs released from the erect thallus. There was no alternation of generations. In winter, the monoecious erect thallus formed reproductive structures (i.e. plurilocular antheridia and oogonia) in the thickened part of the thallus. Sperm had a chloroplast with an eyespot and a long anterior and short posterior flagellum. Eggs contained numerous disc-shaped chloroplasts, physodes, and vacuoles. Neither sexual attraction of the presumptive sperm by eggs nor their sexual fusion was observed. Molecular phylogenetic analyses revealed the closest phylogenetic relationship between Stschapovia and Halosiphonaceae, and they grouped with Phyllariaceae and Tilopteridaceae (Tilopteridales s. s.). Stschapovia and Tilopteridaceae have several important morphological similarities: chloroplasts lacking pyrenoids, lack of sexual reproduction despite the release of obvious sperm, occurrence of monoecious gametophytes, and similarity in the early developmental pattern of the erect thallus. In conclusion, we propose the establishment of the new family Stschapoviaceae to accommodate Stschapovia and the placement of the family in the order Tilopteridales together with Tilopteridaceae, Halosiphonaceae, and Phyllariaceae.