On the basis of skull size, the largest species of Aphelops is A. mutilus (which is the largest North American rhinoceros) and the smallest is the type species A. megalodus.
A. mutilus has been estimated to have weighed 764–1,762 kilograms (1,684–3,885 lb), and A. malacorhinus has been estimated at 889 kilograms (1,960 lb).

Aphelops can be distinguished by other members of the Aceratheriinae by two traits: the arched top of the skull, and the long diastema (gap) between the second incisor (lower tusk) and first premolar.
Many other aspects of its anatomy are typical of aceratheriines, including: the absence of a horn on the broad, unfused nasal bones; the reduced premaxilla and lost first incisor; a nasal incision (or notch below the nasal bones) reaching at least the level of the fourth premolar; a triangular-shaped skull when viewed from the rear; narrow zygomatic arches; brachydont or low-crowned teeth without cement; upper molars bearing a fold of enamel known as an anterocrochet; and lower tusks that are subcircular in cross-section.

More derived (specialized) species have larger teeth and longer, more slender nasal bones (also producing a larger incision).
The various species also differ in the depth of the nasal incision: in A. megalodus, it reaches the front of the fourth premolar; in A. malacorhinus, it reaches the rear of that tooth; and in A. mutilus, it reaches the first molar.
On the basis of skull size, the largest species of Aphelops is A. mutilus (which is the largest North American rhinoceros) and the smallest is the type species A. megalodus. A. mutilus has been estimated to have weighed 764–1,762 kilograms (1,684–3,885 lb), and A. malacorhinus has been estimated at 889 kilograms (1,960 lb).
Aphelops can be distinguished by other members of the Aceratheriinae by two traits: the arched top of the skull, and the long diastema (gap) between the second incisor (lower tusk) and first premolar. Many other aspects of its anatomy are typical of aceratheriines, including: the absence of a horn on the broad, unfused nasal bones; the reduced premaxilla and lost first incisor; a nasal incision (or notch below the nasal bones) reaching at least the level of the fourth premolar; a triangular-shaped skull when viewed from the rear; narrow zygomatic arches; brachydont or low-crowned teeth without cement; upper molars bearing a fold of enamel known as an anterocrochet; and lower tusks that are subcircular in cross-section.
More derived (specialized) species have larger teeth and longer, more slender nasal bones (also producing a larger incision). The various species also differ in the depth of the nasal incision: in A. megalodus, it reaches the front of the fourth premolar; in A. malacorhinus, it reaches the rear of that tooth; and in A. mutilus, it reaches the first molar.
Aphelops