Caenorhabditis brenneri is a gonochoristic (male-female) species closely related to C. elegans (i.e., a fellow member of the Elegans group).
Because C. brenneri was only formally named in 2007, but had been studied for many years before then, it has had several formal or informal synonyms, such as "Caenorhabditis species 4" ("C. sp. 4"), "C. sp. CB5161" (or just "CB5161"), and "C. sp. PB2801" (or just "PB2801"). "CB5161" and "PB2801" are actually the names of commonly used C. brenneri strains.
C. brenneri has the following Web sources of information:
5. A WormBook review of Caenorhabditis ecology (including that of C. brenneri).