南海介螅水母属二新种(刺胞动物门、花水母亚纲、介螅水母科)

Two New Species of Genus Hydractinia from the south China Sea( Cnidaria,Anthomedusae,Filifera,Hydractiniidae)

在分析南海浮游生物样品时,发现了花水母亚纲(Anthomedusae Haeckel,1879)丝螅水母目(Filifera Kühn,1913)介螅水母科(Hydractiniidae L.Agassiz,1862)介螅水母属(Hydractinia van Beneden,1841)2新种:缢介螅水母(H.constrictura sp.nov.)和叶状介螅水母(H.phyllosoma sp.nov.)。缢介螅水母的主要鉴别特征为伞近球形,无顶突;垂管长,其中部有一圈凹缢,把垂管分为2个部分,上端为泡状组织,下端为胃部,上有水母芽,口有4个口腕,口腕末端为刺胞球;生殖腺位于垂管间辐位;4条短的缘触手,触手基球球状,无眼点,触手上具环状刺胞,末端具刺胞球。叶状介螅水母的主要鉴别特征为伞钟形,胶质薄,无顶突;垂管短,无胃柄,口方形,有4个叶片状口唇,口唇上长满刺细胞;生殖腺分布在垂管上,间辐位,无水母芽;4条单生触手。模式标本保存于国家海洋局第三海洋研究所。

Samples of Hydractinia were collected from the South China Sea. Two newspecies of H. constrictura sp. nov. and H. phyllosoma sp. nov. are described in the present paper. The specific diagnosis of the two newspecies is as follows： Hydractinia constrictura sp. nov. Umbrella global-shaped,without apical projection; manubrium long,with a whorl slightly constriction in nearly middle part of manubrium,which is divided into two parts,with vacuolated endodermal cells scattered in upper part of manubrium and no vacuolated cells in lower part; with 4 perradial oral arms,unbranched,each termination with a single knobshaped cluster of cnidocysts; gonads interradial on manubrium,with medusa buds; with 4 marginal tentacles,bulb global,ending in a large cnidocyst knob. Hydractinia phyllosoma sp. nov. Umbrella bellshaped,without apical projection; without gastric peduncle,manubrium short; mouth quadrate,with 4 leaf-like lips with cnidocyst clusters; gonads interradial on manubrium,without medusa buds; 4 marginal tentacles.