Richard Lydekker, 1911 Encyclopædia Britannica, Volume 17… (1911)
“ Nimravus, of the American Oligocene, with two premolars and two molars in the lower jaw, and comparatively short upper canines, seems to be the least specialized type; next to which comes Hoplophoneus, another North American Oligocene genus, in which the tubercular lower molar is lost, and the upper canine is longer. It is noteworthy, however, that this genus retains the third trochanter to the femur, which is lost in Nimravus. Machaerodus, in the wider sense, includes the larger and more typical forms. ”
