Caenorhabditis species 5 is a member of the Elegans group of species, which morphologically resembles C. elegans itself and is closely grouped with it evolutionarily (Kiontke et al., 2011). It is a gonochoristic species, requiring mating between males and females for reproduction, and the closest outgroup to the interfertile pair of hermaphroditic C. briggsae and male-female C. sp. 9. Its geographic distribution is remarkably confined to East Asia (Google Maps), being commonly found in China and northern Vietnam, particularly in habitats with moist decaying vegetation. C. sp. 5 shows strikingly high molecular diversity, assayed by SNP variability (Wang et al., 2010); however, its codon usage patterns are similar to those of C. elegans (Cutter et al., 2008).

Cutter A.D., Wasmuth J.D. and Washington N.L. (2008). Patterns of molecular evolution in Caenorhabditis preclude ancient origins of selfing. Genetics 178, 2093-2104.

Kiontke K.C., Felix M.A., Ailion M., Rockman M.V., Braendle C., Penigault J.B. and Fitch D.H. (2011). A phylogeny and molecular barcodes for Caenorhabditis, with numerous new species from rotting fruits. BMC Evol. Biol. 11,339.

Wang G.X., Ren S., Ren Y., Ai H. and Cutter A.D. (2010). Extremely high molecular diversity within the East Asian nematode Caenorhabditis sp. 5. Mol. Ecol. 19, 5022-5029.