A new and comprehensive taxonomy of all groups of ungulates was recently published by Colin Groves and Peter Grubb (1935-2006). After an insightful introduction covering methods and species concepts, an arrangement is presented of all recent (and a few extinct) ungulate groups. In the Rhinocerotidae, the list includes six species: Rhinoceros unicornis (no subspecies), R. sondaicus (3 subspecies), Dicerorhinus sumatrensis (3 subspecies), Diceros bicornis (8 subspecies), Ceratotherium simum (no subspecies) and C. cottoni (no subspecies). This treatment is very similar to that in previous work by Groves, except for the recognition of the Nile rhinoceros (C. cottoni) as a separate species (Groves et al., 2010) and for the addition of an eighth subspecies of D. bicornis (D.b.occidentalis, separated from D.b.minor).