头刃线虫属一新种（线虫门：垫刃科）

A NEWSPECIES OF THE GENUS Cephalenchus GOODEY,1962(NEMATA:TYLENCHIDAE)

本文描述了在广东省深圳市光明农场的梨树（Ｐｙｒｕｓｓｐ．）根际土中采集到的头刃线虫属（Ｃｅｐｈａｌｅｎｃｈｕｓ）一新种，凹头刃线虫（Ｃｅｐｈａｌｅｎｃｈｕｓｃｏｎｃａｖｕｓｎ．ｓｐ．）。该新种以阴门向体内凹陷，具有较大的外唇和较小的内唇区别于头刃线虫属中的其他种。此外，该新种是这个属中第二个具有４条侧线的种群。该新种在侧线数、体长和口针长等特征上与印度头刃线虫（Ｃｅｐｈａｌｅｎｃｈｕｓｉｎｄｉｃｕｓ（Ｄｈａｎａｃｈａｎｄ＆Ｊａｉｒａｊｐｕｒｅ，１９８０）Ｒａｓｋｉ＆Ｇｅｒａｅｒｔ，１９８６）相似。它们的区别除了阴门特征外，在头部、阴门侧膜、卵巢、后阴子宫囊以及尾长等特征上也存在着明显差异。

Cep halenchus concavus n. sp. collected from soil around roots of pear(Pyrussp.)in Guangdong province is described in this paper.This species is distinguished from theknown species of this genus by vulva sinking in body,with longer outer and smaller innerlips. It is the second species in the genus with four Iateral Iines. Besides vulva characteristic,it differs from the closely related C. indicus(Dhanachand & Jairajpure, 1980)Raski&Ger-aert, 1986 in body thicker(maximum width 19.4(17.4～20. 8)μm vs.15～18μm),headoffset and low(head high 2.6μm vs.3～5μm), conical part ofstylet longer(13.0～14.3um vs.10～12μm),excretory pore place posterior(78.0～80. 6μm from anterior end vs.68～71μm),vulva lateral membranses small(6.2～7.8μm vs.10/～12μm),gonad longer,with curved anterior end,post vulval uterine sac Ionger(20.8～23.4μm vs. 15～17 μm),tail shorter(161. 9(133.9～189. 8)μm vs.184～202μm),ratio of vulva anus distanceand tail about one second(Vs.one third).