Description of Deladenus maraghensis n. sp. (Sphaerularioidea: Neotylenchidae) from East Azarbaijan province, northwestern Iran: a morphological and molecular phylogenetic study

Summary A population of a sphaerularioid nematode resembling the free-living mycetophagous stage of three genera, Deladenus , Hexatylus and Rubzovinema , was recovered from a soil sample collected from the Shur Su (Salty Water) spring region in the city of Maragheh, East Azarbaijan province, Iran. It was typologically compared with the free-living stage of all known species under the three aforementioned genera and was assigned to the genus Deladenus as a new member. The new species was described and illustrated based upon morphological, morphometric and molecular characteristics of free-living females. It is mainly characterised by having a pharyngo-intestinal junction anterior to the nerve ring, just behind the subventral gland orifices, and a secretory-excretory pore between the pharyngo-intestinal junction and hemizonid. Deladenus maraghensis n. sp. is further characterised by a medium body length of females (741-887 μ m), having six lines in the lateral fields, short stylet (6.5-7.0 μ m), vulva at 90.4-92.0%, post-vulval uterine sac (PUS) absent, small lateral vulval flaps present and a 32-38 μ m long conical tail with a rounded tip. The morphological comparisons of the new species with relevant species are discussed. In molecular phylogenetic analyses, sequences of small subunit (SSU) and D2-D3 expansion segments of large subunit (LSU) ribosomal DNA were used and the inferred topologies are discussed.