黄海砂间小型多毛类微目虫属一新种(多毛类:海女虫科)

A NEW SPECIES OF MEIOFAUNA POLYCHAETE MICROPH THALMUS FROM YELLOW SEA (POLYCHAETA: HESIONIDAE)

作者在黄海采集小型底栖动物时,发现多毛类海女虫科微目虫属一新种,命名为双须微目虫。本新种与迄今报导过的微目虫属25个种中,与具钩微目虫和瑞氏微目虫相近,但有明显区别。

All species of Microphthalmus belong to meiofauna, usually several milimeters in length. Microphthalmus species were not reported previously in China. In a study of meiofauna polychaetes from Yellow Sea, a previously undescribed species belonging to the genus Microphthalmus was found from Toudao and Nuerdao near Qingdao. Both holotype and paratype are deposited in the First Institute of Oceanography, State Oceanic Administration, Qingdao, China. The new species is described herein:Microphthalmus biantennatus sp. nov. (figs. 1—2)Holotype complete, length 2.25mm, with 23 chaetigers; width 0.13 mm without parapodia and 0.34mm with parapodia. Paratype uncomplete, length 1.5mm with 14 chaetigers; width 0.5mm with parapodia. Body with dark-brown pigments. Prostomium somewhat semispherical. No pigmented eyes, but one pair of transparent eye spots laterally in posterior part of prostomium. Two cirriform antennae situated dorsally on the anterior margin of prostomium. Median antenna lacking. Palps small, directed anterio-laterally. Six pairs of tentacular cirri on the following segments. Pharynx large with thick muscular wall, located from segments two to five. Chaetigerous segments almost identical throughout. Parapodia biramous. Notopodia reduced strongly, only with one pectinate chaeta possessing six to seven teeth and one notopodial acicula. Dorsal cirri longer than ventral cirri. Dorsal cirri not extending to parapodial lobe. Ventral cirri conical, located at middle part of neuropodial lobe. Four to five compound heterogomph chaetae; blades of which smooth, unidentate and of different length. One stout neuropodial acicula. Pygidium rectangular with anal plate and a pair of slender anal cirri. Margin of plate irregular, without papillae.Twenty-five species of Microphthalmus were reported previously. The lack of midian antenna is a character only for two other species M. riojai Reish, 1962 and M. hamosus Westheide, 1982, which clearly differ from the present one in the shape of parapodia and chaeration.