Kurabayashi Atsushi, Okuyama Makiko, Ogawa Mari, Takeuchi Akira, Jing Zhang, Naganuma Takeshi, Saito Yasunori
Department of Biology, Keio University, Hiyoshi, Yokohama, Kanagawa, Japan.
Zoolog Sci. 2003 Oct;20(10):1243-7. doi: 10.2108/zsj.20.1243.
Ascidians inhabit both shallow water and the deep sea. The phylogenetic position of deep-sea ascidians has not been sufficiently investigated because of their unusual habitats. The family Octacnemidae is one such enigmatic deep-sea ascidian. In this report, we determined the sequences of the 18SrDNA and a mitochondrial protein gene of Megalodicopia hians belonging to the family Octacnemidae, and we analyzed its phylogenetic relationship with other ascidians. A phylogenetic relationship of this family with the families Cionidae and/or Corellidae has been suspected based on a small number of morphological characteristics. However, our results suggested that M. hians has a close relationship to the family Corellidae and might originate from them. This is the first report of the molecular phylogenetic analysis of a deep-sea ascidian.
