Sauropods - the giant long-necked, long-tailed, small-headed vegetarian dinosaurs - traditionally are depicted as having smooth, leatherlike skin.
Actually they had scales, and recent fossil finds in northwestern Wyoming indicate a row of spines on the tail that may have continued along the body and neck, a journal article says.While skin impressions of some kinds of dinosaurs are common, until recently there were only 10 small pieces of sauropod skin impressions known, said the article in the December issue of the journal Geology.
The article was written by Utah resident Stephen A. Czerkas (pronounced Chehr-kus), artist, author and a "self-taught paleontologist" specializing in dinosaur skin. He is studying the skin impressions found in Wyoming.
Paul Sereno, a paleontologist at the University of Chicago, said the rare sauropod skin impressions "look very intriguing." Sereno saw samples Czerkas took to a professional meeting.
"There will be a lot more interest generated in what sauropod skin looked like," Sereno said. "It could mean that one of the sauropods did have a fleshy ornamental along the midline," much like the ruffle running down the backs of Flintstone cartoon dinosaurs, he said.
Czerkas, who with his wife, Sylvia, wrote the book "Dinosaurs - A Global View," became involved with paleontology and dinosaur skin as a result of his work as an artist making dinosaur reconstructions.
When professional collector Kirby Siber reopened the Howe Quarry in northwestern Wyoming in 1990 to gather bones for a Swiss museum and found sauropod skin impressions, Czerkas was contacted.
He visited Siber's team when they started their second season at the quarry in 1991 and arrived in August just after they had found the first spine. Fourteen more were found after that.
The spines ranged from about 11/2 inches to 9 inches. Some were isolated, but others were connected together, indicating they formed a continuous line.
It is not known how far up the tail they went, nor is the pattern of the ornamentation known.
There was no bony core to the spines as there is with armored dinosaurs such as the stegosaurs and ankylosaurs, Czerkas said.
The sauropod spines are keratin, like fingernails and the spines on iguanas. They most closely resemble the iguana spines and those on the tails of alligators and crocodiles.
The crocodile spines are flattened. Some of the sauropod spines are flattened, but others are rounder, more conical. Czerkas believes they may have served the same purpose as the crocodile spines - making the tail more like a paddle and enabling the animal to swim faster.
"Not that they (the sauropods) swam as fast as a crocodile. You don't have to swim fast when you're a vegetarian," he said in a telephone interview from his home near Monticello.
The spines found at the quarry were from a species of sauropod as yet undescribed. "I'm in the process of describing it," he said.
It is like the diplodocus, the barosaurus and the apatosaurus (commonly called the brontosaurus).
The few previous sauropod skin impressions were taken from Howe Quarry in 1933-34. "Unfortunately, most of the impressions were sacrificed while excavating the bones from the quarry," Czerkas said.