The analysis of sequences of three nuclear genes shows that the Diploscapter, Protorhabditis and Prodontorhabditis genera group together to form the 'Protorhabditis' group, the sister group of the Caenorhabditis species, all included in the 'Eurhabditis' group of Rhabditidae genera.[4]
Köhler, Arne (2011). "Description of Halicephalobus similigaster (Andrássy, 1952) and a comparison with its junior synonyms H. minutus (Körner, 1954) syn. n. and H. parvus (Körner, 1954) syn. n. (Nematoda: Panagrolaimidae)". Nematology. 13 (3): 287–293. doi:10.1163/138855410X518489.
The phylogenetic relationships of Caenorhabditis and other rhabditids. Karin Kiontke and David H. A. Fitch, Wormbook, 2005, doi:10.1895/wormbook.1.11.1