Description of n. sp. (Dorylaimida, Nordiidae) from Southern Iran and Its Molecular Phylogenetic Study.

n. sp., a new species of the rare genus is described and illustrated based on its morphological and molecular characters. It was recovered from southern Iran. Females of the new species are characterized by having 1,511.3- to 1,792.5-µm long slender body, angular lip region having prominent papillae, 12- to 13-µm long odontostyle, double guiding ring, simple rod-like odontophore, didelphic-amphidelphic reproductive system, and 102- to 160-µm long elongate-conoid tail with rounded tip. Males of the new species are abundant and functional, characterized by 1,484- to 1,576-µm long body, 40- to 43-µm long spicules, 5 to 6 ventromedian supplements, and ventrally bent elongate conical tail. Compared to the type species, , the new species has differences in its tail morphology and value. These morphological differences and the separation of two species was further supported with basic differences in sequences of 28S rDNA D2/D3 and internal transcribed spacer 1 (ITS1) fragments. Compared to , it has basic differences in tail characters and spicule lengths. Molecular phylogenetic studies using partial sequences of 28S rDNA D2/D3 fragment of the new species and available sequences of Nordiidae members and several other dorylaim species/genera, revealed n. sp. and forming a clade with 0.81 Bayesian posterior probability (BPP). This clade forms a sister clade to the clade of sp. and , again with 0.81 BPP. In ITS1 tree, reconstructed using few available sequences, the new species and formed a clade with 0.98 BPP.