Izumi Takato, Ise Yuji, Yanagi Kensuke, Shibata Daisuke, Ueshima Rei
1 Department of Biological Sciences, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
2 Sugashima Marine Biological Laboratory, Graduate School of Science, Nagoya University, Sugashima, Toba, Mie 517-0004, Japan.
Zoolog Sci. 2018 Apr;35(2):188-198. doi: 10.2108/zs170042.
A new species in a new genus of sea anemone, Tempuractis rinkai gen. et sp. nov., was discovered at several localities along the temperate rocky shores of Japan. The new species is approximately 4 mm in length and has been assigned to family Edwardsiidae, because it has eight macrocnemes, lacks sphincter and basal muscles, and possesses rounded aboral end. The sea anemone, however, also has a peculiar body shape unlike that of any other known taxa. This new species resembles some genera, especially Drillactis and Nematostella, in smooth column surface without nemathybomes or tenaculi, but is distinguishable from them by several morphological features: the presence of holotrichs and absence of nematosomes. Furthermore, this edwardsiid species exhibits a peculiar symbiotic ecology with sponges. Therefore, a new genus, Tempuractis, is proposed for this species. In the field, T. rinkai sp. nov. was always found living inside homosclerophorid sponge of the genus Oscarella, which suggests a possible obligate symbiosis between Porifera and Actiniaria. The benefit of this symbiosis is discussed on the basis of observations of live specimens, both in the aquarium and field. This is the first report of symbiosis between a sea anemone and a homoscleromorph sponge.
在日本温带岩岸的多个地点发现了海葵新属中的一个新物种——环海温盘海葵（Tempuractis rinkai gen. et sp. nov.）。该新物种体长约4毫米，被归入艾氏海葵科（Edwardsiidae），因为它有8条大型触手，没有括约肌和基部肌肉，口盘末端呈圆形。然而，这种海葵也具有独特的体型，与其他已知分类群不同。该新物种在光滑的柱体表面没有刺丝囊或小刺，这一点与一些属，特别是钻孔海葵属（Drillactis）和星状海葵属（Nematostella）相似，但在一些形态特征上又与它们有所区别：有全毛细胞且没有刺胞体。此外，这种艾氏海葵科物种与海绵呈现出独特的共生生态。因此，为这个物种建立了一个新属——温盘海葵属（Tempuractis）。在野外，新种环海温盘海葵总是被发现生活在奥斯卡雷拉属（Oscarella）的同骨海绵体内，这表明多孔动物门和海葵目之间可能存在专性共生关系。基于在水族箱和野外对活体标本的观察，讨论了这种共生关系的益处。这是关于海葵与同骨海绵共生关系的首次报道。
