A NEW CRICONEMATID NEMATODE,OGMA HECHUANENSIS N.SP.(TYLENCHIDA: CRICONEMATIDAE) IN CHINA

Ogma hechuanensis n.Sp.was Collected from soil around roots of Citrus sp.in Hechuan County,Sichuan Province,China.This species differs distinctly from all the other Ogma spp.described.Female body longer,751~967um,gently curved ventrad.Lip region rounded with four large submedian lobes.Head annuli two,smooth and set off from the body.The first annulus,divided into 4,5 or 8 sectors (usually 4),much larger than the second in diameter,but smaller than the third one (the first body annulus).On the third annulus 8-10 scales presrnt.The number of rows increases to 10-13 (regularly 11-12) in the middle of the body and decreases at the vulva region.Stylet stronger,117-138um long while cone is 85-105um.Distance from head end to excretory pore,to the end of esophagus and to vulva 225-286 (253),167-211 (192) and 678 -884 (777) um,respectively.Ovary extends forward and some even exceed stylet knob.R=64-74 (69).Rcxp=19-22 (21).Vulva and anus near tail end,Rv=5-7 (6),Ra=2-4 (3).Tail tip rounded with several scales.a=9.5-13.6 (11.7),b=3.9-4.8 (4.4),c=17.7-33.7 (23.3),v=88.9-92.6 (90.9).Male and juvenile forms unknown.Ogma hechuanensis n.sp.is related to O.querci,but differs in the diameter of two head annuli,rows of scales in middle body,stylet length,R,and other characteristics.Type habitat and location: soil around roots of Citrus sp.in Hechuan County,Sichuan Province,China.All slides are deposited in the Lab.of Forest Pathology,Inst.of Forest Res.,Chinese Academy of Forestry,Beijing,China.