Some free-living nematode species of the genus Mesodorylaimus (Nematoda: Dorylaimidae) from Chaharmahal va Bakhtiari province

In order to study the Dorylaimid nematode 150 soil samples were collected from different localities in Chaharmahal va Bakhtiari province, during 2009 to 2011. Nematodes were extracted by combined sieving and centrifugal – flotation technique and processed to be transferred in glycerin by De Grisse (1969) method. After preparing microscopic slides, the morphological and morphometrical features werestudied using the light microscope equipped with drawing tube. In this study five species including M. vulneratus, M. graciosus, M. pseudobastiani, M. ibericus and M. litoralis belonging to Mesodorylaimus were identified, that the first four species are new for the nematode fauna of Iran. Vulva has a transverse slit in three first species in spite of longitudinal slit in the two latter. Lip region was observedoffset in M. vulneratus while continuous with body in M. ibericus and M. graciosus. Odontostyle in M. ibericus was shorter than M. graciosus. M. pseudobastiani and M. litoralis can be distinguished by different number of supplements in males.