Skrjabinomermis pirnaimi sp. n. (Nematoda: Mermithidae) from Iran: A morphological and molecular phylogenetic study

A new species of the genus Skrjabinomermis, collected from two locations in north and northwest of Iran, is described and illustrated, including morphological data and D2-D3 rRNA LSU sequences. Skrjabinomermis pirnaimi sp. n. is characterised by its six cephalic papillae, two hypodermal pegs in the area of the cephalic papillae, adult’s cuticle with very fine cross fibres, head rounded, mouth central, amphids cup-shaped, six hypodermal cords, vulva a transverse slit, located post-equatorially, cuticular protruding and vulval lips well developed, vagina pear- or barrel-shaped, with slightly bent lumen, tail similar in both sexes, bluntly rounded, spicules paired, medium sized, slightly curved, fused posteriorly for about 68-73% of their length, with pointed tip, male genital papillae arranged in three rows: the median ventral row having two pre- and two post-anal papillae, and the lateroventral rows with five papillae each. Molecular analyses using the D2-D3 expansion regions of the 28S rRNA gene sequences placed the genus Skrjabinomermis as a sister genus to Romanomermis with 93% Bayesian posterior probability based upon currently available data.