Laimydorus zehsaziani n. sp., a new member of the genus from northwest of Iran, with additional data on Labronema vulvapapillatum (Meyl, 1954) Loof & Grootaert, 1981 (Dorylaimida: Dorylaimidae).

A new species belonging to the genus Laimydorus, and a known species of the genus Labronema, collected from the rhizosphere of grassland plants in West Azarbaijan province, Iran, are presented. The new species is characterized by its body length (1.56-1.81 mm in females and 1.39-1.57 mm in males), lip region offset by weak constriction and wider than adjacent body (11-14 μm), odontostyle 17-20 μm long, neck length 312-434 μm, vulva longitudinal (V = 42.2-46.5), uterus well-developed and with Z-differentiations, tail long (219-237 μm, c = 6.9-8.3, c´ = 8.2-10) in females, short and convex-conoid with blunt terminus (19-22 μm, c = 68-72.5, c´= 0.77-0.84) in males, spicules 40-45 μm long, and 18-20 contiguous ventromedian supplements with hiatus. Molecular analyses, using Bayesian inference based on D2-D3 expansion segments of the 28S rRNA (LSU), placed the new species in a clade comprising representatives of the genera Nevadanema, Dorylaimus, Labronema, Calcaridorylaimus, Mesodorylaimus, and Prodorylaimus, which all belong to Dorylaimidae. In addition, new data (molecular, morphometrics, images, and geographic distribution) are presented for the Iranian population of Labronema vulvapapillatum.