Odd, spiky dinosaur likely used self-sharpening teeth for self-defense.

A new, tiny dinosaur with vampire-like fangs devoured ... plants?

So says a new study of Pegomastax africanus, a 2-foot-long (0.6-meter-long) heterodontosaur that lived about 200 million years ago. (Test your dinosaur IQ.)

Heterodontosaurus was a genus of small, fanged dinosaur species that were "scampering around between the toes of other dinosaurs at the dawn of the dinosaur era," said study author Paul Sereno, a National Geographic Society explorer-in-residence. (National Geographic News is a division of the Society.)

Covered in porcupine-like quills and sporting a blunt, parrot-like beak, P. africanus would've looked like a "strange little bird," said Sereno, a paleontologist with the University of Chicago.

But its fangs, Sereno argues, were more like those of the piglike peccary (picture) or fanged deer, or water chevrotain (video)—modern-day, plant-eating mammals that use their teeth for self-defense and foraging.

The species, he added, would have lived along forested rivers in southern Africa around the time the supercontinent Pangaea had just begun to split into the northern and southern landmasses.


Reconstructing the Oddball

While preparing a comprehensive analysis of the little-known heterodontosaurs, Sereno identified P. africanus from fossils at Harvard University, which had been collected in South Africa in the 1960s.

To find out what the newfound dinosaur did with its sharp fangs, Sereno then reassembled P. africanus' jaw and teeth. He compared the reconstruction to jaws and teeth of both meat-eating dinosaurs and modern plant-eating mammals with fangs.

Sereno discovered that P. africanus' fangs were very similar to those of fanged deer and peccaries, which use their fangs in self-defense and competition for mates, he said.

Supporting this theory, microscopic analysis of P. africanus' fang enamel revealed wear and breakage consistent with sparring.

The researcher suggested too that the cheek teeth in P. africanus' upper and lower jaws worked like self-sharpening scissors for shearing plant parts, as detailed in the study, published online Wednesday in the journal ZooKeys.

Tiny Dinosaur Ahead of Its Time

Finding a new species of heterodontosaur is not "all that noteworthy," Hans-Dieter Sues, a vertebrate paleontologist at the National Museum of Natural History in Washington, D.C., said by email.

"But [Sereno's] comprehensive review of the entire group of these odd little dinosaurs is a landmark contribution," said Sues, who wasn't involved in the study. (Read about bizarre dinosaurs in National Geographic magazine.)

In particular, Sues is impressed that Sereno "worked out how these dinosaurs chewed their food, which helps understand their peculiar, molar-like teeth."

What's more, the study revealed that P. africanus' sophisticated jaw structure was ahead of its time, Sereno noted. Such structures evolved again millions of years later in mammals.

If the housecat-size dinosaur lived today, he quipped, "it would be a nice pet—if you could train it not to nip you."

Christine Dell'Amore
National Geographic News
-------------------
http://news.nationalgeographic.com/news/2012/10/121003-new-dinosaur-species-fanged-sereno-science/
http://www.redorbit.com/news/science/1112706119/dinosaur-pegomastax-africanus-100312/