Baby dino reveals secrets
and World Science staff
With its big, hockey puck-sized eyes, shortened face and nubby horns, it was probably as cute as a button—at least to its mother, a three-horned dinosaur called Triceratops who could weigh as much as 10 tons (9,000 kg).
Visitors to the University of California, Berkeley’s Valley Life Sciences Building now can judge for themselves. Displayed there is a cast of the foot-long skull of what scientists say is youngest known Triceratops fossil. It’s dwarfed by the more than six-foot-long skull of an adult Triceratops, who had one of the biggest skulls of any land animal.
The university’s Mark Goodwin described the actual skull, which is in pieces at the school, in the March issue of the Journal of Vertebrate Paleontology. He argued that the find suggests horns weren’t used only for sexual display, as commonly believed, but to help animals recognize each other.
Despite the pup’s size, he said, its remains are revealing much about how dinosaurs grew, the purpose of their head ornaments and the characteristics of their ancestors. In particular, since the horns and frill are present from a very early age, it is unlikely they served only for sexual display, he argued.
The baby skull shows characteristics—a shortened face and big eyes—that scientists believe have made babies lovable throughout the ages, Goodwin added. The horns grow to three feet in the adult, while the scalloped edges of the frill, which can grow to seven feet across, become more wavy and develop scales.
“The horns and frill of the skull likely had another function other than sexual display or competition with rivals, which people have often argued, and allows us to propose that they were just as important for species recognition and visual communication in these animals,” Goodwin said.
Triceratops horridus was a strictly North American dinosaur, though relatives with different but equally formidable ornamentation roamed China and Mongolia during the Cretaceous period, 65-144 million years ago, Goodwin explained.
Adult Triceratops could be nearly 10 feet tall and 26 feet long, with a bony frill around the head that was as wide as seven feet across. Two three-foot horns typically curved forward from the brow, while a third horn erupted from the nose above a narrow, horny beak.
The baby’s skull, along with other bone fragments, were discovered by amateur fossil hunter Harley Garbani in 1997 in Montana’s Hell Creek Formation, the source of many Triceratops and T. rex fossils. Goodwin assembled the pieces into a skull and lower jaw that is missing the nose and beak.
The fossil has been a unique addition to the world’s existing, mostly adult specimens of Triceratops, Goodwin said. The skull of the roughly year-old baby, he added, fits into a study he is conducting with Jack Horner of Montana State University about the growth patterns of Triceratops and other dinosaurs.
The skull surface shows grooves where blood vessels used to be, which apparently nourished a fingernail-hard covering coating, Goodwin argued. Such horny coverings are often brightly colored in the living descendents of dinosaurs—the birds—suggesting Triceratops may have been colorful, too.
The baby’s hazelnut-sized brain , hidden beneath the bony frills of the skull, fit snuggly within protective bones not yet fused, so as to allow further brain growth, he noted. In the adult, the brain, about the shape and size of a small sweet potato, was encased in fused bones.
“The baby skull shows us how the bones that make up the skull actually grew and fit together,” he said. “It’s an incredible specimen, with beautiful preservation.” Goodwin and Horner also have made casts of the skull for the American Museum of Natural History in New York and for Montana’s Museum of the Rockies.
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