Morphological and molecular characterization of Leptonchus granulosus Cobb, 1920 (Dorylaimida: Leptonchidae) from Iran

Leptonchus granulosus, recovered from Lorestan province, is described and illustrated based on morphological, morphometric and molecular data. The Iranian population of the species is characterized by its body length of 1091 - 1374 mm, cuticle distinctly two layered, outer layer finely annulated, inner layer distinctly annulated, being partly separated from the body and shriveled after fixation, cap-like lip region separated from the rest of body by constriction, distinctly sclerotised walls of prestoma and stoma, delicate needle-like odontostyle with distinct narrow lumen, 8.0-9.5 mm long, slightly arcuate odontophore, 17-21 mm long, with arms slightly thickened at base, small pear-shaped pharyngeal bulb, occupying 16.6-24.3% of pharynx length, simple intestine, very long prerectum (617-663 µm long), its junction with intestine having three distinct guard cells located between anterior ovary and cardia, didelphic female reproductive system, composed of equally sized less developed tracts, but with distinct parts (tubular uterus, simple oviduct and ovary), conoid to hemispheroid tail and absence of males. In comparison with the available reports of the species, no remarkable variation in morphometric data ranges was observed.
This is the first representative of the genus for Iran’s nematode fauna found so far. Molecular phylogenetic studies of Iranian population of L. granulosus using 1669 nt partial sequences of 18S rDNA revealed it forming a clade with another isolate of the species in Bayesian inference (BI) with 0.95 Bayesian posterior probability (BPP).