They were previously thought to be members of the genus Cervus, but were moved to Rucervus based mainly on morphological differences. Based on genetic evidence, the Eld's deer should be moved back to Cervus, while the two last species remain in Rucervus or –less likely– could be moved to Axis.
Following the third edition of Mammal Species of the World from 2005, three species are placed in Rucervus, but the Eld's deer should be split into two species.
- Rucervus duvaucelii - barasinga or swamp deer
- Rucervus eldii - Eld's deer or brow-antlered deer
- Rucervus schomburgki - Schomburgk's deer (extinct, 1938)
Furthermore, it has also been suggested that the Eld's deer should have its own genus, Panolia, and is closer to Père David's deer.
- Pitraa, Fickela, Meijaard, Groves (2004). Evolution and phylogeny of old world deer. Molecular Phylogenetics and Evolution 33: 880–895.
- Groves (2006). The genus Cervus in eastern Eurasia. European Journal of Wildlife Research 52: 14–22
- Wilson, D.E.; Reeder, D.M., eds. (2005). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. ISBN 978-0-8018-8221-0. OCLC 62265494.
- Groves (2006). The genus Cervus in eastern Eurasia. European Journal of Wildlife Research 52: 14-22.