Molecular and morphological characterisations of two new species of Rotylenchus (Nematoda: Hoplolaimidae) from Iran

Two new amphimictic species, Rotylenchus iranicus n. sp. and R. conicaudatus n. sp., are described. Rotylenchus iranicus n. sp. is characterised mainly by an offset hemispherical lip region with 5-6, rarely 7, annuli, stylet 39-44 μm long, vulva located at 53-65% and rounded tail with 4-9 annuli and typical smooth tip. Morphologically this species is related to R. montanus, R. provincialis and R. aqualamus. Rotylenchus conicaudatus n. sp. is characterised mainly by a slightly offset conoid-rounded lip region with four or five, rarely six annuli, stylet 27-32 μm long, vulva located at 52-63% and conoid-rounded tail with 10-16 annuli and a typical annulated tip. Morphologically this species is related to R. pumilus, R. abnormecaudatus, R. acuspicaudatus and R. provincialis. The results of the phylogenetic analysis based on sequences of the D2-D3 expansion regions of 28S and ITS1-rRNA genes confirmed the species differentiation. Phylogenetic relationships with other species were difficult to assign using D2-D3 expansion regions of 28S. However, using ITS1-rRNA, R. conicaudatus n. sp. presented a close relationship with R. unisexus, whilst R. iranicus n. sp. was closely related to R. conicaudatus n. sp., R. unisexus, R. incultus and R. laurentinus.