Baby dino had adult-like bite

London, Oct 25 : The analysis of a rare baby dinosaur skull has confirmed that it had meat-tearing canine teeth normally associated with adults.

According to a report in New Scientist, the fossil of Heterodontosaurus, the dino in question, was newly identified after being examined in a South African museum.

The 45-millimetre skull has features characteristic of a juvenile - large "puppy dog" eye sockets, and a snub nose, with adult-like meat-tearing canine teeth.

Intriguingly, while it has canines at the front of the mouth, it also has molars behind - a pattern more often seen in mammals.

"It's exceptionally rare to see that pattern of teeth in a reptile," said Richard Butler, a palaeontologist at the Natural History Museum in London.

"Mammals typically have well differentiated canines at front of the jaw and molars at the back, but reptiles generally have a single pattern of teeth all along the tooth row," he added.

Heterodontosaurus was one of the earliest members of a group of herbivorous dinosaurs - the "bird-hipped" ornithischians.

Some palaeontologists have suggested that Heterodontosaurus chewed vegetation with its molars, while the canines were purely for display - like those of a male warthog.

But only adult skulls had been found until now, so the theory was impossible to confirm.

The new baby skull, though, changes that. The presence of canines strongly suggests that Heterodontosaurus still had a penchant for meat.

"The fact that the canines were present so early in growth suggests it's not a sexual dimorphic character seen only in (adult) males," said Butler.

"We suspect the most probable function is dietary, and it's likely these animals would have incorporated some small animal matter into their diet," he added.

Also, palaeontologists suspect that Heterodontosaurus replaced its teeth when it was young, just like mammals.

CT scans of adult skulls seemed to confirm the replacement theory, since they showed no signs of any new teeth growing deep within the jaw.

But, when the baby skull was scanned, no evidence was found of budding replacement teeth here either.

"We know tooth replacement must have been very unusual in this animal," said Butler. "Perhaps there were short phases of replacement and long periods where it wasn't occurring. That's unlike any other reptile I'm aware of," he added.

ANI