Skip to main content

New Species of Plant-Eating Dino Was Lunch for Prehistoric Crocs

Right femur of the new herbivorous dinosaur that houses the broken tooth from an ancient crocodile relative.
Credit: Clint Boyd.

Sometimes, the fossil record gives us some really exciting insights into prehistoric life – including grisly details of prehistoric death. Paleontologists have found evidence not only of a new species of herbivorous, or plant-eating, dinosaur, but also that these dinosaurs were preyed upon by the prehistoric forebears of crocodiles.

Seventy-five million years ago, southern Utah looked more like southern Louisiana – a mixture of swampland and flood plains with rivers. To date, paleontologists have found that the landscape may have supported around seven different varieties of prehistoric crocodyliforms, ancient relatives of today’s crocodiles. These pre-crocs ranged in size from about 6 feet to 40 feet in length.

Enter the hapless herbivore. From fossil remains found on a hilltop in southern Utah, paleontologists have discovered evidence – including scratches on the bones and a predator’s tooth fragment – that these early crocodile relatives fed on a previously undiscovered herbivore.

The fossils in question belong to several individuals of the new dinosaur, which was a relatively small, at least for dinosaurs, plant-eater distantly related to duckbill dinosaurs or Iguanodon. They indicate that the victims were less than a year old and 6 to 7 feet in length – about the same size as the predator who ate them.

“Reconstructing the events that led to fossil sites is tricky business.  We know the identity of the victims, how old they were, and how they were buried,” says Terry Gates, NC State paleontologist with a joint appointment at the North Carolina Museum of Natural Sciences and a co-author of a paper describing the find. “What we don’t know, is the species of crocodyliform that ate them, or whether the herbivores were living or dead when they were consumed.”

The new species of herbivore was identified by Clint Boyd, lead author of the paper and paleontologist at the South Dakota School of Mines and Technology. The findings appear in PLOS One.  Stephanie K. Drumheller, a paleontologist affiliated with the University of Iowa and the University of Tennessee, contributed to the work. The specimens are reposited at the Natural History Museum of Utah, Salt Lake City, and come from the Bureau of Land Management, Grand Staircase Escalante National Monument.