A revision of the genus Metarhabditis (Nematoda: Rhabditidae) with description of three known species,a key to the identification of congeners and discussion of their relationships

The taxonomy of the genus Metarhabditis is discussed with an emended diagnosis and a key to identification of its species. Three known species of Metarhabditis are described and illustrated. Metarhabditis amsactae (Ali et al. 2011) Sudhaus, 2011, a species recently transferred to the genus, is described in detail and its relationship with other congeners is discussed. The present population of Metarhabditis costai (Martins, 1985) Sudhaus, 2011 shows some minor differences with the original population in having slenderer individuals with relatively greater ‘a’ value, relatively smaller spicules and gubernaculum. Some minor differences are also noted in the present population of Metarhabditis andrassyana Tahseen et al. 2004 from the original population. The present population has distinct lateral fields, faint longitudinal striae, a nearly undifferentiated corpus and a relatively posteriorly located third genital papilla in males.