Helicotylenchus spitsbergensis, A..L O O F, 1971

P. A. A. LOOF, 1971, FREELIVING AND PLANT PARASITIC NEMATODES FROM SPITZBERGEN, COLLECTED BY MR. H. VAN ROSSEN, Mededelingen Landbouwhogeschool Wageningen 71, pp. 1-86 : 43-45

Helicotylenchus spitsbergensis n.sp. ( Fig. 12 ).

Dimensions:

Females (n = 8): L = 0.79- 1. 08 mm; a = 28 -38; b = 6.5 -8.1; c = 36 -42; V = 21 '2956-68 18 - 24.

Female, holotype: L = 0.91 mm; a = 38; b = 7. 3; c = 42; V = 236224. Male not found.

Body usually coiled into more than one convolution. Transverse striation distinct, about 1.5 [x apart on middle of body. Lateral field one-third as wide as body, with four longitudinal lines. Lip region continuous, hemispheroid, composed of four to five rather indistinct annules. Spear length 27- 31 |x (holotype 28 (x), the two parts of almost equal length- Spear knobs indented anteriorly. The dorsal oesophageal gland orifice lies 8 -9 [x behind the base of the spear. The median bulb lies at 64-71 % of total oesophagus length from head end (measured till junction ol lumen with mid-intestine). The oesophageal glands overlap the mid-intestine on all sides over fair distance, the ventrosublateral glands generally sligthly farther than the dorsal one. The excretory pore lies about six annules anterior to the oesophago-intestinal junction; the hemizonid is two annules long and lies one to two annules anterior to the excretory pore.

Vulva transverse. Vagina one-half of body width deep, with conspicuously cuticularized walls. Gonads paired, opposed and outstretched, each with an empty spermatheca which lies within the gonad, not dorsally of it. No eggs. Tail trapezoid to conoid, 1.3-1.4 anal body widths long, the posterior margin usually truncate; there are about 13 annules between anus and ventral terminal angle. Posterior margin distinctly, sometimes irregularly, striated. Tail slightly curved to ventral side. The cuticle is composed of two well-demarcated layers. Phasmids distinct, located from two annules before to three behind the anus.

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Holotype: Female on slide WT 1126. Paratypes: Seven females on slides WT 1127-1131 and 1139.

Type habitat and locality: Sample 40. Paratypes also from samples 23, 25, 43 and 44. Juveniles found in sample 18.

This species is very close to H.platyurus Perry, 1959 , from which it is distinguished by the spermatheca not being offset. From H.cavenessi Sher, 1966 ( Nigeria) it differs by the same character and by being much longer and having a longer spear. From H. serenus Siddiqi, 1963 ( India) it differs by larger body size, relatively shorter oesophagus and truncate tail.

Figures

FIG. 12. Helicotylenchus spitsbergensis n.sp., female. A: neck region; B: part of reproductive system; C: tail