For decades, paleontologists have held up uintatheres as a prime illustration of sexual dimorphism, or the tendency for males and females of a species to be physically different. Notable for their large size, prominent horns and canine teeth, uintatheres emerged about 58 million years ago, fewer than 10 million years after a space rock killed the dinosaurs, and show up in the fossil record for the next 20 million years or so.
'Classic example' of sexual dimorphism in fossil record actually shows nuance between males and females
