武陵山地区鱼类寄生杆咽属线虫两新种

STUDES ON TWO NEW SPECIES OF RHABDOCHONA(PAPASITIC NEMATODES)FROM WULINGMOUTAIN REGION

本文报道在武陵山地区的白甲鱼［（Ｖａｒｉｃｏｒｋｉｎｕｓ（Ｏｎｙｃｈｏｓｔｏｍａ）ｓｉｍｕｓ（ＳａｕｖａｇｅｅｔＤａｂｒｙ）］和沪溪直口峻（ＲｅｃｔｏｒｉｓｌｕｘｉｅｎｓｉｓＷｕｅｔＹａｏ）中发现的两种杆咽属（Ｒｈａｂｄｏｃｈｏｎａ）线虫新种，定名为白甲鱼杆咽线虫，新种（ＲｈａｂｄＯｃｈｏｎａｏｎｙｒｋｏｓｔｏｍｉｓｐ．ｎｏｖ．）和短咽杆咽线虫，新种（ＲｈａｂｄＯｃｈｏｎａｂｒｅｖｉｃｈｏｎａｓｐ．ｎｏｖ．），并对两新种进行了测量和详细的描述。

During April-June and October-December,1988, 929 fish belonging to 59 specieswere examined in Wuling Mountain Region,and 24 species of nematodes were collected andidentified.There are six species belonging to the genus Rhabdochona Railliet,1916,and twoof them are new to science. The new species are Rhabdochona onychostomi sp.nov;andR. brevichona sp.nov. Descriptions(measurements in millimeter)are given as follows:1.Rhabdochona onychostomi sp.nov.Host:Varicorhinus(Onychostoma)simus(Sauvage et Dabry)Location:Intestine.Locality:Yinjiang County,Guizhou Province; Qianjiang County,Sichuan Province.Specimens:Holotype(1♂),allatype(1♀)and paratype(4♂4♀)are deposited in theLaboratory of Fish Diseases,Institute of Hydrobiology, The Chinese Academy of Sciences.Description:Medium-sized nematode. Buccal capsule cup-shaped, with 4 basal teeth;the anterior margin anned with 6 teeth.Nerve ring located near the anterior extremitv ofmuscular oesophagus. Excretory pore located near or anterior to the middle of muscularoesophagus.Cervical papillae bifurcate, and located near the middle of pharynx. Male:(5 specimens) Length of body 5.883-9.368.Maximum width 0. 101-0.110.Buccal capsule 0.017-0.020 long and 0.011-0.012 wide. Pharynx 0.105-0.129 longand 0.004 wide. Length of muscular oesophagus 0.290-0.375, and that of glandularoesophagus 2.510-3.216. Nerve ring 0.147-0.185,excretory pore 0.247-0.297 and cervicalpapillae 0.070-0.082 from anterior extremity.Seven pairs of preanal papillae,the fifth later-al,and others subventral,distance between the sixth pair and the seventh pair shorter thanbetween others.Seven pairs of postanal papillae, the second pair lateral,and otherssubventral.Left spicule thin and elongate and 0.777-0.840 in length.Right spicule thickand short,and 0.079一0.080 in length.Length ratio of spicules 9.5:1.Tail curvedventrally,its length 0.241-0.295,with a saw-tooth-like or blunt tip.Felnale:(5 specimens) Length of body 16.541-23.295. Maximum width 0.161-0.241. Buccal capsule 0.021-0.024 long and 0.012-0.013 wide, Pharvnx 0.110-0.121 longand 0.004-0.005 wide. Length of muscular oesophagus 0.401-0.437,and that of glandularoesophagus 4.073-5.478. Nerve ring 0.174-0.182, excretory pore 0.287-0.308 and cervicalpapillae 0.077-0.08 3 from anterior extremity.Tail provided with processes,0.351-0.413long. Vulva postequatorial.Distance between the vulva and anterior extremity 8. 758-12.114, and that between the vulva and posterior extremity 7.783-11.181; the ratio of thetwo distanees 1.1:1.Size of mature eggs 0.035一0.038×0.021-0.025(n=20). Discussion: This species is different from other nematodes in that its nerve ring is relative-ly close to the anterior extremity of muscular oesophagus;the tail is long; tail of the female isprovided with processes,the length ratio of spicules in the male is rather high; and there are 7pairs of postanal papillae.R. onychostomi is very similar to R. fujianensis Wang,1986,but the former has longerleft spicule(0.777-0.840)than the latter(0.544-0.560),and bears 7 instead of 6 pairs ofpreanal papillae;the tail of the female in the fonner is provided with processes.2.Rhabdochona brevichona sp.nov. Host:Rectoris luxiensis Wu et Yao Location:Intestine. Locality:Qianjiang County,Sichuan Rrovince. Speimens: Holotype(1♂),allotype(1♀), andparatype(1♂3♀)are deposited in theLaboratory of Fish Diseases, Institute of Hydrobiology, The Chinese Academy of Scienees.Description: Medium-sized nematode, Buccal capsule funnel-shaped,with 2 poorly de-veloped basaI teeth; anterior margin anned with 8 teeth.Pharynx very short, about twice asbuccal capsule. Cervical papillae bifurcate,and located near the base of buccal capsule.Male:(2 specimens) Length of body 6.95 1-7.202.Maximum width 0.096-0.110.Buccal capsule 0.021-0.024 long and 0.011 wide. Pharynx 0.045-0.046 long and0.003 wide. Length of muscular oesophagus 0. 193-0.236, and that of glandular oesophagus1.528-1.554. Nerve ring 0.169-0.174, excretory pore 0.224-0.255 and cervical papillae0.024-0.029 from anterior extremity. 7 pairs of preanal papillae, the seven