Ischiodorylaimus istvani, A New Dorylaimid Species (Nematoda) from India with Revised Key to the Species Under Genus Ischiodorylaimus Andrássy, 1969

One new limnetic nematode species Ischiodorylaimus istvani sp. n. belonging to the genus Ischiodorylaimus Andrássy, 1969 described here was collected from the rhizospheric soil of pumpkin ( Cucurbita pepo L.) from the district North 24-Paganas, West Bengal, India. The present species is medium in size (♀: 4.7–4.8 mm; ♂: 4.2 mm). Cardia tongue-shaped. Vagina obliquely placed, enclosed in a thick muscular sheath. Tail short and filiform (260–267 μm in length) in females. Males with ventromedian supplements arranged in 19 + 5 + 19 manner along with one ad-anal papilla. Supplements provided with well developed copulatory pads. Large spicule with lateral guiding pieces. Tail in male rounded conoid (47.5 μm in length) with 10 caudal pores. A revised key to species is given.