广西沿海真唇水母属一新种

Abstract

记述来自广西沿海真唇水母属(EuCHEIlOTAMCCrAdy,1859)一新种——双手真唇水母(EuCHEIlOTA bITEnTACulATAHuAng,lI ET zHOng SP.nOV.).其鉴别特征如下:伞钟罩形,胶质薄;垂管短,口方形;生殖腺在辐管中部,肾形,当中充满卵细胞;4条辐管,1条环管;缘触手2条,相对排列,另2个相对的主辐缘疣,触手和主辐缘疣均有3对侧丝,4个间辐位缘疣无侧丝,触手和缘疣均无黑色素;8个平衡囊.还讨论真唇水母有效种及本新种与近似种的区别,同时提供中国海域真唇水母属已知有效种的检索表.模式种保存于厦门大学海洋与环境学院.

Samples of Eucheilota collected from Beilun Estuary(108.017°--108.233°E,21.514°--21.645°N) and Qinzhou Bay(108.485°--108.858°E,21.563°--21.867°N) in Guangxi in August 2009.One new species of Eucheilota bitentaculata Huang,Li et Zhong sp.nov.is described.The specific diagnosis of the new species is as follow:umbrella dome shaped,jelly thin;manubrium short,mouth quadrangular with four simple lips;gonads on media of radial canals with very egg cells;four radial canals and one cycle canal;two opposite marginal perradial tentacles and two opposite marginal perradial warts,all with three pairs of lateral cirri;four interradial warts without lateral cirri,all tentacles and warts without black pigment;8 marginal vesicles,each with a concretion.The new species belongs to Genus Eucheilota McCrady,1859.20 species of Eucheilota in the world were reported by Bouillon et al.including two undefined species of Eucheilota.Eucheilota intermedia Kubota,1984 were corrected to Eutima japonica Uchida,1925.Guo et al.Considered that Eucheilota diademata Kramp,1959 was larva of Eutima krampi Guo,Xu et Huang,2008.Bouillon et al.Regarded Eucheilota taiwanensis Xu et Huang,1990 is a doubtful species,but more probably corresponds to the E.paradoxica Mayer,1900.In fact,the two species differed in the morphological characteristics.E.taiwanensis,medusa-buds near stomach;with four perradial marginal tentacles,each with two pairs of lateral cirri;interradial marginal wart with black pigmentation.E.paradoxica,medusa-buds on the middle part of radial canals;with four perradial marginal tentacles,each with only one pair of lateral cirri;interradial marginal wart without black pigmentation.So E.taiwanensis is a valid species.In short,valid species of Eucheilota in the world are 16 species,but only one species of Eucheilota with two marginal tentacles i.e.Eucheilota backeri(Toney,1959).E.backeri with two perradial marginal tentacles and two perradial marginal warts,without interradial marginal warts;tentacles with one pair of lateral cirri;wart without lateral cirri;only two gonads and four marginal vesicles.But the new species,two marginal perradial tentacles and two marginal perradial warts,all with 3 pairs of lateral cirri;with 4 interradial warts without lateral cirri;with 4 gonads and 8 marginal vesicles.So the new species differs from E.backeri.