Four species of squat, plant-eating dinosaurs unearthed in Utah are filling a gap in the record of reptiles that roamed Earth 100 million to 120 million years ago.
The new dinosaurs — tank-like ankylosaurs and nodosaurs found at College of Eastern Utah digs — sport tough armor to protect them from predators like the utahraptor, a 7-foot-tall, 20-foot-long carnivore with 9-inch, razor-sharp claws.
“They had little, teeny, wedge-shaped heads and big, fat bodies like a short-legged cow with a crocodile tail,” said paleontologist Don Burge, director of the CEU Prehistoric Museum in Price.
The dinosaurs, which were discovered over the last decade, were presented last week at the annual meeting of the Society for Vertebrate Paleontology.
Why They’re Different
Burge and CEU field party leader John Bird tried to show how the species differed from each other, with Burge comparing the presentation to a copyright or patent on the specimens. “It gives them formal acceptance in the scientific community.”
One of the new finds, Bilbeyhallorum, belongs to the family Ankylosauridae, which lacked spiny armor but had clublike tails.
The other three — Gastonia burgei, Animantarx ramaljonesi and an unnamed elephant-size dinosaur — had spiny armor but no tail clubs and belong to the family Nodosauridae.
The four species span a gap between the Jurassic Period, more than 147 million years ago, and the Late Cretaceous Period, about 70 million years ago.
Pelvic Bone Key to Gastonia
Gastonia burgei was found in the early 1990s by Rob Gaston, who uncovered a 2- to 3-foot-long bony plate from the dinosaur’s pelvic area.
Other fossils were later uncovered by Gaston, Burge and Kirkland. To date, more than 1,300 remnants of the Gastonia burgei — named for Gaston and Burge — have been found.
“Gastonia is a marvelous creature,” said Burge. “Imagine a horny toad blown up to 17 feet. He had shoulder spikes that resemble thorns on a rose but are over a foot long. On both sides of the tail and neck, it had rows of big plates that looked like the triangular dorsal fin on a great white shark. The tail could whip around and cut you bad.”
In 1995, University of Utah radiation analyst Ramal “Ray” Jones, working with Burge and others, discovered the Animantarx ramaljonesi in Cedar Mountain rocks east of Castle Dale.
Rare Armadillo Cousin
The 12-foot-long dinosaur resembles an armadillo and has rowboat-shaped cups of armor. Fewer than 100 Animantarx fossils have been found.
The third dinosaur, tentatively named Bilbeyhallorum, was found two or three years ago by Vernal paleontologist Sue Anne Bilbey and her husband, Evan Hall, on a dig with Burge and Bird at a CEU quarry 20 miles southeast of Price.
It was reported to be 30 feet long, but Burge now believes it was 17 feet long. So far parts of a juvenile and two adults have been excavated.
The fourth, unnamed dinosaur was discovered in the same quarry last year by Bird and his crew.
“It’s a monstrous thing,” Burge said. “He’s as big as an elephant.”
The dinosaur weighed 4 to 5 tons and was 30 feet long. Burge said the armor “looks like barnacles on a ship — knobby things like on a crocodile head.”