Plant-eating dinosaurs coexisted by munching different vegetation

Two kinds of large herbivorous dinosaurs that lived side by side had skulls that allowed the creatures to specialize in feeding on different plants, researchers report October 8 in the Proceedings of the Royal Society B.

Diplodocusand Camarasaurus were members of the iconic group of enormous, long-necked dinosaurs known as sauropods. Around 150 million years ago during the Late Jurassic, at least 10 sauropod genera roamed North America in a semiarid environment that offered sparse vegetation.

Researchers took CT scans and created simulations of both dinosaurs’ skulls. By looking at marks on the bones where muscles would have attached, the researchers also reconstructed musculature.

Camarasaurus, with a short, heavy jaw, had stronger muscles and the more powerful bite of the two dinosaurs. Diplodocus, with a long, thin jaw, had a weaker bite.

Camarasaurusprobably used its powerful bite to crunch through woody conifers. Diplodocus probably grazed on ferns and horsetails, grasping plants and tugging with its strong neck to strip them bare, the researchers conclude.

The dinosaurs’ environment was far from lush, yet growing to a large size helped sauropods, especially in times of drought. “You can be so big you are a massive water and fat store, and travel long distances efficiently,” says David Button, the lead author and a paleontologist at the University of Bristol in England.