Triceratops, Torsaurus same dino at different stages of growth

July 15th, 2010 - 2:42 pm ICT by ANI  

Washington, July 15 (ANI): A new American study has debunked over a 100 years of thought regarding the dinosaurs known as Triceratops and Torosaurus. Both the reptiles are actually the same dinosaur at different stages of growth, according to the research.

Since the late 1800s, scientists have believed that Triceratops and Torosaurus were two different types of dinosaurs. Triceratops had a three-horned skull with a rather short frill, whereas Torosaurus had a much bigger frill with two large holes through it.

Writing in the July 14 issue of the Journal of Vertebrate Paleontology, Montana State University paleontologists John Scannella and Jack Horner, say their discovery contributes to an unfolding theory that dinosaur diversity was extremely depleted at the end of the dinosaur age.

The confusion over Triceratops and Torosaurus was easy to understand, Scannella said, because juvenile dinosaurs weren’t just miniature versions of adults. They looked very different, and their skulls changed radically as they matured. Recent studies have revealed extreme changes in the skulls of pachycephalosaurs, tyrannosaurs and other dinosaurs that died out about 65 million years ago in North America.

Scannella, a doctoral student in earth sciences, said: “Paleontologists are at a disadvantage because we can’t go out into the field and observe a living Triceratops grow up from a baby to an adult. We have to put together the story based on fossils. In order to get the complete story, you need to have a large sample of fossils from many individuals representing different growth stages.”

The Triceratops study suggests that it is critical that paleontologists consider ontogeny (growth from a juvenile to an adult) as a source of major morphological variations before naming new species of dinosaurs to account for variation between specimens, Scannella added.

Scannella said: “Without considering changes in shape throughout ontogeny, we overestimate dinosaur diversity and hence produce an unrealistic view of the paleoecology of these animals.”

Scannella and Horner, Regents Professor of Paleontology at MSU’s Museum of the Rockies, examined more than 50 Triceratops specimens for their study.

They measured the length, width and thickness of the skulls, and examined the microstructure, surface textures and shape changes of the frills. Microscope studies revealed that the tissues of Torosaurus specimens are more heavily remodelled than those of even the largest Triceratops, strongly suggesting that Torosaurus specimens are in fact adult Triceratops, Scannella said. Even in Triceratops that were previously considered to be adults, the skull was still undergoing dramatic changes.

Scannella said he and Horner tried for three years to look for alternative explanations for their findings. They finally agreed that the Triceratops and Torosaurus were the same dinosaur.

Scannella said: “Every avenue of investigation we took in attempts to falsify the hypothesis only supported the idea further.” (ANI)

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