莽山后棱蛇Opisthotropis cheni Zhao,1999的再描述(Serpentes:Colubridae)(英文)

A Re-description of Opisthotropis cheni Zhao, 1999(Serpentes: Colubridae)

作者于1999年根据湖南宜章莽山标本发表新种莽山后棱蛇Opisthotropis cheni的鉴别特征,现对该蛇加以详细描述.莽山后棱蛇是小形水栖蛇,全长500～600 mm,尾长占全长的五分之一左右,身体圆柱形,头较小,与颈区分不明显.鼻间鳞前端窄,鼻孔背侧位;眼小,背侧位;前额鳞单枚,甚宽,其两外侧扩展至头侧; 颊鳞长,后端入眶;无眶前鳞,眶后鳞2;颞鳞1+2(1);上唇鳞8 (3-2-3)为主;下唇鳞10,前4或5枚接前颔片;颔片2对,前对约为后对长的2倍.背鳞通身17行,除最外行其余微棱,腹鳞159～167,肛鳞二分,尾下鳞55～59对.背面暗橄榄褐色,体侧具多数淡黄色横斑,左右横斑彼此交错或在背中线相连;腹面色白或偶有灰点斑.雄性头腹前端鳞片(如颏鳞、颔片和前4～5对下唇鳞)上有多数疣粒,雌性则无.此蛇见于山溪或小河流水中,白昼隐藏于岩洞、石下、沙砾或杂草间,晚上或黄昏外出活动觅食,共采到5号标本,其中4号均采于晚上20～22点之间,1号采于18点左右;被捕捉的蛇离水后两三天就死掉.此蛇也曾见于农耕地灌溉渠旁的杂草中.

Colubrid species Opisthotropis cheni Zhao, 1999 was named by the author five years ago （see inside front cover of number 3, volume 18 of Sichuan Journal of Zoology）, but a diagnosis was given only. In this paper a re-description for the newly known species is contributed, and CIB series-number of three of the types preserved in Chengdu Institute of Biology is also given here.