 "E. crassus" is currently the only species of "Emeus", as the other two species, "E. casuarinus" and "E. huttonii" are now regarded as synonyms of "E. crassus".It has been long suspected that the "species" described as "Emeus huttonii" and "E. crassus" were males and females, respectively, of a single species.This has been confirmed by analysis for sex-specific genetic markers of DNA extracted from bone material; the females of "E. crassus" were 15-25% larger than males.