It had pitifully small teeth inside its weak jaws, and a huge pot belly hung like a kettle over its broad hips and cumbersome legs. It looked like a slightly daffy ostrich-dinosaur mutant with slothlike claws on the ends of its feathered arms.
But this ungainly creature - called a Therizinosaur - is the star of a new exhibit opening Saturday at Arizona Museum of Natural History in Mesa. Dubbed "Therizinosaur: Mystery of the Sickle-Claw Dinosaur," the display introduces a strange new addition to the North American prehistoric roster.
"As bizarre as dinosaurs are, I think this is the most bizarre of all. You couldn't have imagined it as a cartoon if you tried," says David Gillette, the Museum of Northern Arizona paleontologist who dug up the 93 million-year-old creature's bones.
A skeleton made of casts of those bones is the centerpiece of the exhibit.
Excavated in 2000 from Utah shale northwest of Lake Powell, the dino is the most complete Therizinosaur skeleton ever found. It's also one of only three Therizinosaurs ever uncovered in North America. Prior to their discovery in the past decade, all previous evidence of sickle-clawed dinos came from Asia.
Also special about the skeleton is where it was found: sunken beneath the Cretaceous Western Interior Seaway, a salt-water channel teeming with giant, predatory fish, sharks and nautiloids that, almost a billion years ago, split the Western side of North America.
Since Therizinosaur was a terrestrial creature, one has to wonder why its life came to an end so far out to sea.
"That's one of the many mysteries," says Gillette, who will give a special presentation on the dinosaur during the exhibit's opening on Saturday. "We have a real good handle on the dimensions of it. We know it was a waddler, not a runner. We know it had feathers. We know its ancestry is from carnivorous dinosaurs, but at some point, it went over to plant-eating. There are a lot of unanswered questions."
The museum skeleton is the first mounted interpretation of the 13-foot-tall, 1-ton animal's stance and posture. The exhibit also features an 8-foot-by-8-foot re-creation of the excavation site, replicas of sea and air creatures of the day, touchable items, and artists' renderings of Therizinosaur in its heyday.
"This dinosaur is going to be the main skeleton of reference for study of this type of dinosaur," says Gillette. "We're unraveling a whole new dinosaur right here in the Southwest."