Horned and duck-billed dinosaurs dominate
Ceratopsians and hadrosaurs evolve grinding dental batteries and become the great herds of the age.
- When
- —
- Duration
- 2 million years
- Known to
- ± 2 million years
- Era
- Cretaceous, Mesozoic
The last Cretaceous herbivore faunas are dominated by two ornithischian groups with a shared innovation: dental batteries of hundreds of interlocking teeth forming a continuously replaced grinding surface, capable of processing tough plant material far more thoroughly than any sauropod could. Ceratopsians such as Triceratops add enormous frills and horns, most likely for display and species recognition as much as defence. Hadrosaurs such as Parasaurolophus add resonating cranial crests. Bonebeds of thousands of individuals show both moved in large herds.