Discopersicus hexagrammatus n. sp. (Rhabditida: Tylenchidae), the second species of the genus

Abstract

Discopersicus hexagrammatus n. sp., is described and illustrated from a population associated with the rhizosphere of carrot ( Daucus carota L.) in Dezful, Khuzestan province, south-western Iran. Based on morphological and morphometric data, the new species is characterized by a 601-734 µm long body, a prominent perioral labial disc and oblique amphidial slits, 10-11 µm long stylet, vulva at 65-67% of body length, 15.5-17 µm long spicules, and an elongate conoid tail with a pointed terminus. It is the second species of the genus Discopersicus and differs from its counterpart D. iranicus, by its anterior position of vulva, shorter stylet, lower M.B. ratio, different shape of tail tip, and shorter spicules in male specimens. A molecular phylogenetic analysis using the D2-D3 expansion segments of 28S rDNA sequences, placed the new species in close relationship with five sequences of the genus Boleodorus .