|
 Scientists on Tuesday unveiled a comprehensive analysis of the
teeth of the group of carnivorous dinosaurs called theropods,
detailing a unique serrated structure that let them chomp
efficiently through the flesh and bones of large prey.
Theropods included the largest land predators in Earth's history.
They first appeared about 200 million years ago and were the
dominant terrestrial meat-eaters until the age of dinosaurs ended
about 65 million years ago.
The study involving eight theropod species revealed their previously
unknown tooth complexity. Internal dental tissues were arranged in a
way that reinforced the strength and prolonged the life of teeth
that were serrated like steak knives for easy dismembering of other
dinosaurs.
University of Toronto Mississauga paleontologist Kirstin Brink said
fossil evidence showed that T. rex's teeth could crush bone. Its
teeth have been found embedded in the bones of its prey and chunks
of bone appear in its fossilized dung.
"But the serrations were most efficient for piercing flesh and
gripping it while ripping off a chunk of meat, called the 'puncture
and pull' feeding style," Brink said.
The researchers analyzed slices from fossil teeth using a powerful
microscope and a sophisticated device that revealed tooth chemical
properties.
They studied teeth from: the early and relatively small Coelophysis;
bird-like Troodon; large predators Allosaurus, Gorgosaurus,
Daspletosaurus, Tyrannosaurus and Carcharodontosaurus; and big,
semi-aquatic Spinosaurus.
The teeth of Tyrannosaurus and Carcharodontosaurus measured up to 9
inches (23 cm) long.
[to top of second column] |
"In theropods, the serrations are larger and deeper than the
superficial view suggests, making them stronger and longer lasting,
less likely to get damaged or worn," University of Toronto
Mississauga paleontology professor Robert Reisz said.
Dinosaurs were able to continuously grow teeth throughout their
lives. When a tooth was broken, another could replace it.
"It could take up to two years for a tooth to grow back in the big
theropods like T. rex. Therefore, having specially reinforced teeth
means less tooth breakage and less gaps in the jaw, leading to more
efficient eating," Brink said.
The Komodo dragon, a lizard up to 10 feet (3 meters) long from
Indonesia, is the only living reptile with serrated teeth closely
resembling those of theropods although these teeth evolved
independently of those of the dinosaurs, Brink said.
The research appears in the journal Scientific Reports.
(Reporting by Will Dunham; Editing by Sandra Maler and Eric Walsh)
[© 2015 Thomson Reuters. All rights
reserved.]
Copyright 2015 Reuters. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed.
 |
