Characterisation of a new species of Trichodorus Cobb, 1913 (Triplonchida: Trichodoridae) from Iran based on morphological and molecular data.

Trichodorus zanjanensis n. sp., collected from the rhizosphere of wild almond tree (Amygdalus scoparia Spach) in Zanjan Province, Iran, is described and illustrated based on morphological and molecular data. The new species is characterised by its body length (772-819 μm in males; 704-953 μm in females), and in having medium-sized onchiostyle (60-64 μm in males; 59-65 μm in females) and a short dorsal overlap of the intestine. Males of the new species have two ventromedian cervical papillae posterior to onchiostyle region, ventrally curved spicules, smooth, long and wide manubrium, gradually continuing in a narrower anterior part of the blade provided with bristles and marked from the wider and transversely striated main part of the blade, tapered towards distal end, three ventromedian precloacal supplements, the posterior one (SP1) situated at the level of anterior blade and gubernaculum situated at 24-25 μm from the cloaca. Females have one pair of sublateral body pores in the vulva region, medium rounded triangular to oval sclerotised vaginal pieces in lateral view, and pear-shaped vagina. The new species resembles T. persicus De Waele & Sturhan, 1987, T. minzi De Waele & Cohn, 1992 and T. taylori De Waele, Mancini, Roca & Lamberti, 1982. The results of morphological and morphometric comparisons and molecular data based on sequences of the partial 18S and D2-D3 expansion segments of 28S rRNA genes, clearly separated T. zanjanensis n. sp. from these known species and supported the description of T. zanjanensis n. sp. as a new species.