Smallest Meat-Eating Dinosaur in N. America Discovered

Matt Kaplan
for National Geographic News
March 16, 2009

North America's newest dinosaur had the makings of a monster: razor-sharp claws, a runner's body, and similarities with the Velociraptor of Jurassic Park infamy.

If only it'd been bigger than a chicken.

At 19 inches (50 centimeters) tall, 75-million-year-old Hesperonychus elizabethae is North America's smallest known carnivorous dinosaur, a new study says.

In many ways the new dinosaur species, found in Alberta, Canada, looks to have been a miniature of its distant cousin Velociraptor.

But careful analysis of Hesperonychus's features suggests that the new species was more closely related to more obviously birdlike dinosaurs: four-winged Microraptor (Microraptor picture) and feathered Sinornithosaurus.

Why Tiny Dinosaurs Are a Big Deal

To paleontologists, small, rare finds are often better than big.

When an animal dies, its remains can be utterly destroyed any number of ways.

Predators or scavengers can eat the body and chew up the bones. Wind, rain, rivers, and surf can break and wear away at a carcass. Even buried bones barely stand a chance, thanks to heat, erosion, and underground pressure.

Beset by such forces, small bones hardly stand a chance, which explains why paleontologists are so enthusiastic about finding a pint-sized predator in 75-million-year-old Canadian rock.

"It's neat to find such a small critter," said Kevin Padian, a paleontologist at the University of California, Berkeley, who was not involved in the study, to be published tomorrow in the journal Proceedings of the National Academy of Sciences.

Near Miss

The enormity of the tiny find was nearly missed by the dinosaur's discoverer.

"When the specimen was first collected, it was so small that it never even occurred to the collector that this was a dinosaur, even though she had collected lots of dinosaurs before," said study co-author Phillip Currie, a University of Alberta paleontologist.

Closer examination revealed that the hip bones of the little predator were similar to those of Velociraptor—establishing the new specimen as a dinosaur.

The hip bones were also fused, a condition usually seen only in adults—suggesting the specimen was not a baby.

With only digits and a pelvic girdle to go by, that's one of the few things researchers currently understand about Hesperonychus.

Without more bones, Berkeley's Padian said, "we don't know what the rest of this new animal looked like."

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