Phylogenetic relationships of Cacopaurus pestis Thorne, 1943 within representatives of the Tylenchulidae Skarbilovich, 1947 as inferred from ITS and D2-D3 expansion segments of 28S-rRNA sequences.

Summary: The Persian sessile nematode (Cacopaurus pestis) and pin nematodes (Paratylenchus spp.) are sedentary ectoparasitic nematodes associated with many plant species worldwide. In this study, we provide morphological and molecular characterisation of seven populations of C. pestis and eight species of Paratylenchus recovered from north-western Iran. A total of 26 new sequences of D2-D3 expansion segments of 28S rRNA and ITS rRNA were obtained and used to reconstruct phylogenetic trees. Results of phylogenetic analyses revealed that the subfamilies of Tylenchulidae form well-separated clades, but that the genera Cacopaurus and Paratylenchus (= Gracilacus) in the subfamily Paratylenchinae are clustered in one clade. It appears that the previously used character of "stylet length greater than 40 μ m" is not homologous and evolved more than once within the Paratylenchinae. [ABSTRACT FROM AUTHOR]