Description and molecular characterization of Coslenchus iranicus n. sp. (Rhabditida: Tylenchidae) from Iran.

Coslenchus iranicus n. sp., recovered from the rhizosphere of soapwort in South Khorasan province, Eastern Iran, is described based on morphological and molecular data. The new species is characterized by its cuticle with 18 longitudinal ridges excluding lateral lines, lateral field with three incisures, lip region unstriated, stylet 9.4-12.0 µm long, spermatheca filled with sperm, post-vulval uterine sac absent, vulva with large vulval flaps, and tail mostly with a pointed terminus, though in a few specimens with a finely rounded tip. Based on general characterization, C. iranicus n. sp. is closely similar to C. areolatus, C. franklinae, C. japonicus, C. leiocephalus, and C. maritus. The phylogenetic relationships of the new species with representatives of the family Tylenchidae were reconstructed and discussed using partial sequences of the small subunit, D2-D3 expansion segments of the large subunit, and internal transcribed spacer regions of ribosomal DNA based on Bayesian inference. In the SSU rDNA and LSU rDNA phylogenetic trees, sequences of the new species formed clades with corresponding sequences of C. polonicus and C. leiocephalus with different levels of relatedness, respectively.