FREELIVING AND PLANT PARASITIC NEMATODES FROM SPITZBERGEN, COLLECTED BY MR. H. VAN ROSSEN Author P. A. A. LOOF Department of Hematology, Agricultural University, Wageningen, The Netherlands text Mededelingen Landbouwhogeschool Wageningen 1971 1971-12-31 71 1 86 journal article 10.5281/zenodo.8152982 dc936e39-ea56-4501-b5ba-a24d055276c8 8152982 85C9CB49-EEA1-467B-ACC7-7C11B9EDEEAD Eudorylaimus vanrosseni n.sp. ( Fig. 27 ; Diagram 6). Dimensions: Females (n = 8): L = 1.03-1.25 mm ; a = 23- 29; b = 3.5-4.3; c = 35-40; V = 1 3 _ 1 854 - 5713 - 1 8. Female, holotype : L = 1.05 mm ; a = 27; b = 3.6; c = 38; V = 135615. Male unknown. Body rather stout, curved ventrad slightly in death. Cuticle 2.5- 3.0 [x thick, increasing to 6 u, on ventral side of tail; with thin, sharply demarcated outer layer which shows fine but distinct transverse striae. Lateral chord about 30 % of body width. Lip region offset by a shallow constriction; lips separate, angular. Amphid aperture about 60 % of corresponding body width. Length of odontostyle 16-17 (JL, i.e. slightly more than width of lip region, the aperture occupying about one-third of its length. Basal portion about 25 \i long. Guiding ring 'single'. The nerve ring surrounds the oesophagus at about 35 % of its length from head end. Cardia conspicuous, subglobular, variable in size (12-20 X 15- 27(1). Oesophageal characters ( two females ): The oesophagus begins to widen at 51- 53 % and attains its full width at 57- 60 % of its length from head end. DO lies at, or just anterior to the latter level, the distance DO- DN is 13 -14 \i. The SiN lie a small distance apart, behind the middle of the distance DN - S2N; the anterior one is small and indistinct, the posterior one large and conspicuous. The S2N are well developed and lie rather close to the base of the oesophagus. Locations: DO 57 -59 %; SjN^ 77-78 %; S2N 90-93 %; K = 85 - 93; D N 62 -63 %; SjN2 79- 80 %; S20 92- 93 %; K ' = 94. DO- DN 4.6 %; dist. 1.6-2.7 %; Vulva of the transverse type , vagina wide, half body width deep. Gonads two, opposed, reflexed, without sperm; with constriction between uterus and oviduct. Tail shaped as in E.monohystera : convex-conoid, indented dorsally, tip round­ ed; its length 1.0-1.3 anal body widths. Rectum 1.2 - 1.3 anal body widths long, prerectum one to two times as long as rectum. Tail with a row of (usually 6) small ventral saccate bodies. Holotype : Female on slide WT 1134 . Paratypes : Seven females on slides WT 1221-1224 . Type habitat and locality: Sample 55. Paratypes also from sample 53. Diagnosis: This species resembles E.pratensis (de Man, 1880) in tail shape, but this species has a much longer and thinner odontostyle. From E. nitidus (Thorne & Swanger, 1936) it differs by the well-developed, separate lips; from E.obesus (Thorne & Swanger, 1936) by the distal part of the tail ventrally not being offset, and by the shorter odontostyle (against 22 \x) with shorter aperture; from E.albionensis (van der Linde, 1938) by the non-sinuate ventral tail contour, lower lip region, post-equatorial vulva and lower ratio odontostyle/lip region ( 1.5 in albionensis ).