Hypothesis of the phylogenetic relationships of Amblydorylaimus isokaryon (Loof, 1975) and Pararhyssocolpus paradoxus (Loof, 1975), gen. n. comb. n. based on 18S rDNA of closest species (17 sequences) inferred from a Bayesian analysis using GTR+G model and midpoint rooting of the tree. Posterior probabilities higher than 0.8 are presented. Species coloured according the classification of Andrássy (2009a) and Peña-Santiago and Álvarez-Ortega (2014): dark blue – fam. Aporcelaimidae, light blue – fam. Actinolaimidae, green – fam. Dorylaimidae, red – fam. Qudsianematidae.