Morphology and systematics of the superfamilies Leptolaimoidea Örley, 1880 and Camacolaimoidea Micoletzky, 1924 (Nematoda: Plectida)

Dagda bipapillata, Deontolaimus papillatus, Leptolaimus mixtus, Paraplectonema loofi sp. n., Rhadinema flexile and Stephanolaimus elegans are described on the basis of new material from Europe and the Americas. Dagda bipapillata is studied by SEM for the first time. Paraplectonema loofi sp. n. is described from Costa Rica and differs from all other species of the genus by the position of excretory pore on lip region. Leptolaimus primitivus Gagarin, 2001 is transferred to Paraplectonema. A revised classification of the superfamily Leptolaimoidea is proposed based on a phylogenetic analysis of a set of morphological data of most genera of the group and a reappraisal is made of the superfamily Camacolaimoidea including the families Camacolaimidae and Rhadinematidae. The taxonomy of Leptolaimus is discussed. First description of a male of Odontolaimus chlorurus is given. It is characterised by the presence of five setiform sensilla along the ventral side of the pharyngeal region and no precloacal supplementary sensilla. New information on the male of Tobrilia imberbis is provided. The systematic positions of the genera Bastiania, Odontolaimus and Tobrilia are reconsidered. Emended diagnoses are given for the families Leptolaimidae, Camacolaimidae and Rhadinematidae