Cervus is a genus of deer that primarily are native to Eurasia, although one species occurs in northern Africa and another in North America. In addition to the species presently placed in this genus, it has included a whole range of other species now commonly placed in other genera. Additionally, the species-level taxonomy is in a state of flux.
Until the 1970s, Cervus also included the members of the genera Axis, Dama, and Elaphurus, and until the late 1980s, it included members of Rucervus and Rusa.[1]
In the third edition of Mammal Species of the World from 2005, only the red deer (C. elaphus) and sika deer (C. nippon) were recognized as species in the genus Cervus.[1] Genetic and morphological evidence suggest more species should be recognized.[2][3] For example, the species Cervus canadensis (elk/wapiti) is considered a separate species.[4]
Within the red deer species group, some sources have recommended the Central Asian red deer (Cervus hanglu) should be treated as a species.[2][4][5] If the Central Asian red deer (from the Caspian Sea to western China) is recognized as a species, it includes the Yarkand deer and Bactrian deer (the two may be synonymous), but it could possibly also include the Kashmir stag, which has not been sampled in recent studies.[2][4] If it is included in the Central Asian red deer, the scientific name of that species is C. hanglu. If it is not included, the scientific name of that species is C. yarkandensis, and the Kashmir stag (C. hanglu) may represent a separate monotypic species.[2][4] The Central Asian red deer was considered its own species (including the Yarkand deer, Kashmir stag and Bactrian deer as subspecies) by the IUCN in 2017,[6] and by the American Society of Mammalogists in 2021.[7]
Others members of the red deer group, which may represent separate species, are C. corsicanus, C. wallichi and C. xanthopygus.[2][3] If so, C. corsicanus includes the subspecies C. c. barbarus (perhaps a synonym of corsicanus), and is restricted to Maghreb in North Africa, Corsica and Sardinia.[2][4] C. wallichi would probably include the subspecies C. w. kansuensis and C. w. macneilli (both are perhaps synonyms of C. w. wallichi), and would be found from Tibet to central China.[2][4][8] C. xanthopygus would probably include the subspecies C. x. alashanicus (perhaps a synonym of C. x. xanthopygus), and would be found from the Russian Far East to northeastern China.[2][4][8] This would restrict the "true" red deer (C. elaphus) to Europe, Anatolia, the Caucasus and northwestern Iran, and the elk/wapiti (C. canadensis) to North America and the Asian regions of the Tian Shan, Altai, and Great Khingan.[2] Alternatively, the barbarus group species are subspecies of the "true" red deer, while the C. wallichii and C. xanthopygus groups are subspecies of the elk/wapiti.[4]
It has been proposed that the sika deer should be split into four species based on genetics, morphology and voice,[3] although this may be premature based on the presently available evidence.[9] If split, the potential species are C. yesoensis from northern and central Japan (Hokkaido and northern and central Honshu), C. nippon of southern Japan (southern Honshu, Shikoku, Kyushu, Okinawa, Tsushima and other small islands), C. hortulorum of mainland Asia (the Russian Far East, Korea, central and eastern China and northern Vietnam), and C. taiouanus of Taiwan.[3]