Rhinos or Horses?

Though not a rhinoceros and much more closely related to horses, Megacerops was a very rhinoceros-like relative of horses and is therefore a bit confusing on first glance. Known more popularly as Brontotherium, Megacerops Leidy 1870 was far larger than any modern horse or rhinoceros. Its distinctive look, two large bony protuberances above its nose, make it look slightly more like a rhinoceros, but are significantly different from any known rhinoceros horn as well. The use of these protuberances is well documented, as we shall discuss. This animal is yet another North American Eocene mammal.

Robert Bruce Horsfall, 1913