گزارش گونه های Rhyssocolpus iuventutis Andrassy 1971 و Crassolabium kaszabi (Andrassy 1959) Peña-Santiago & Ciobanu 2008 از ایران

Soil samples collected from the rhizosphere of different plants in natural habitats in Zanjan province during 2021 and studied two species, namely, Crassolabium kaszabi and Rhyssocolpus iuventutis, were identified as new record for Iran's nematode fauna. Members of the genus Rhyssocolpus belonging to the Nordiidae family with distinguished from Heterodorus species by having small odontostyle (up to 13 μm long, often only up to 10 μm long) and always shorter than the lip region diam., bipartite uterus and no refractive granules in the narrow part adjacent to the sphincter and hyaline cells surrounding it, and presence of very strong cuticular irregularities in the vulval area. Iranian population of the species R. iuventutis is distinguished from closely related species by its rather longer body, 1/2-1/5 mm long, lip region nearly continuous and 12- 13 μm broad, odontostyle 8/5-9/1 μm long with very small aperture, guiding ring double, tail conical and curved ventrad with 33-46 μm long (c = 27-35, c'= 0/9-1/2), female genital system amphidelphic, V=49-52., spicules 49-57 μm long and 7-9 spaced ventromedian supplements. The genus Crassolabium belongs to the Dorylaimidae family is separated from other genera in the family by having a body length ranges from 0/6-2/1 mm, Lip region slightly offset from body contour; lips somewhat separate, guiding ring simple, odontostyle often little robust and 1/5 times the labial width long, Tail in both sexes short, rounded or convex-conoid, vulva transverse and rarely longitudinal, dorylamoid spicules and 3-18 ventromedian supplements. Iranian population of the species C. kaszabi is separated from closely related species by its medium body size, 1-1/2 mm long, odontostyle 11 μm long, vulva transverse,V=58-60, tail rounded conoid with 15-17 μm long (c = 67-73, c' = 0/6-0/7), spicules 38-40 μm long, and 12-16 ventromedian supplements.