Eastern Moa
The eastern moa, Emeus crassus, is an extinct species of moa. When the first specimens were originally described by Richard Owen, they were placed within the genus Dinornis as three different species, but, was later split off into their own genus, Emeus. 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. This phenomenon — reverse size dimorphism — is not uncommon amongst ratites, being also very pronounced in kiwis.