A new species of the genus Hexamermis Steiner, 1924 (Nematoda: Mermithidae) from northern Iran: a nematode with an unusual uterine morphology.

Hexamermis zirabi sp. n., recovered from a natural habitat of Mazandaran province, north of Iran, is described based on morphological and molecular data. The new species is characterized by its six cephalic papillae; cuticle with distinct cross fibers; conoid or sharply tapered head; mouth terminal; six hypodermal cords; J-shaped vagina oriented to the anterior end of body; uterus with Z-organs or sclerotized bodies; tail similar in both sexes and bluntly rounded; spicules paired, separate, slightly curved, shorter than body width at cloaca, with rounded tip; and male genital papillae arranged in five rows. In addition to the morphological study, molecular phylogenetic analyses using a partial large subunit (28S D2-D3) were also performed, and the new species formed a highly supported (1.00% Bayesian posterior probability (BPP)) clade with Hexamermis popilliae.

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.

Study of two species, one new and one known, of the genus Aporcella Andrássy, 2002 (Dorylaimida, Aporcelaimidae) from Iran, with a note on its phylogeny.

Two species of the genus Aporcella, one new and one previously known, collected from cultivated fields in Iran are studied. Description, morphometrics, illustrations (both line and microphotographs) and D2-D3 sequences are provided for Aporcella talebii sp. n., which is characterized by its 1.66-2.02-mm-long body, lip region offset by constriction and 15-17 µm broad, odontostyle 14-17.5 µm long, neck 412-484 µm long, pharyngeal expansion occupying 46-50% of total neck length, uterus simple and 1.6-2.0 times the corresponding body diameter long, V = 52-59, tail conical (40-50 µm, c = 37-47, c' = 1.1-1.4) with a weak but perceptible dorsal concavity at the end and male absent. Morphometrics, microphotographs and D2-D3 sequences of Aporcella simplex are also presented, this being its first Asian record. Molecular analyses confirm the monophyly of the genus, its close relationship with other taxa lacking pars refringens vaginae and the polyphyly of Aporcelaimidae.