The molar is plane and hypsodont : the crowns are relatively high and the main cusps are about as high as the other parts of the crown, As in closely related species, the front part of the molar is relatively simple, lacking an anteroloph, an additional ridge that is well-developed in most oryzomyines.
32.
Its primitiveness is suggested by the retained paraconids on the lower molars . " Eomorphippus ", a Mustersan notohippid, was moderately hypsodont, Deseadan genera such as " Thynchippus " and " Eurygenium " were very high-crowned, and Santacrucian genera had acquired cementum on the crowns similar to equids.
33.
The single known molar is high-crowned ( hypsodont ) and flat-crowned ( planar ) and is distinctive in lacking the ridge that connects the front to the middle part of the molar, the anterior mure, and in the configuration of another ridge, the mesoloph . " Carletonomys " was probably herbivorous and lived in a wet habitat.
34.
Among the two Arrisdrift species, " M . gariepensis " is about 15 % smaller than the East African " M . pentadactylus " and more adapted to jumping and has less robust incisors, more high-crowned ( hypsodont ) cheekteeth . " M . aegaeus " and " M . pentadactylus " differ in details of the crowns of the cheekteeth.
