Courtesy Mark RyanOthniel C. Marsh must be spinning in his grave… again. Two more of the dinosaurs the Yale paleontologist named in the late 19th century have been determined to be the same genus. It’s not that big a surprise. More than a hundred years ago Marsh and his arch-nemesis Edward Drinker Cope were in such a hurry to outdo each other during the infamous “Bone Wars” they were naming new genera and species left and right, and as fast as they could get them out of the ground.
In 1889 Marsh’s best field collector, John Bell Hatcher uncovered the first Triceratops remains in Wyoming. Marsh named it Triceratops (which means “three horned-face” because of the horns projecting from its nose and frill. Two years later, Hatcher unearthed a similar horned dinosaur that Marsh christened Torosaurus (“pierced lizard”).
Courtesy Mark RyanBoth creatures had three horns but Triceratops’ bony frill was a continuous fan shape, while the Torosaurus’ frill was longer and had two large oval openings (fenestrae). This difference in configuration led Marsh to believe he had discovered two different types of dinosaurs.
But now a new study by paleontologists from Montana State University says the Triceratops and Torosaurus genera are one and the same, and the former is just a younger, immature version of the latter. Under the International Code of Zoological Nomenclature (ICZN) rules of nomenclature the name of the earlier discovery takes precedence. The research appears in the latest issue of the Journal for Vertebrate Paleontology, and was led by paleontologists John Scannella, and Jack Horner.
Misnaming dinosaurs isn’t that uncommon (see previous Buzz post ). Fossils originally thought to be from different genera or species are often - after further study - determined to be from the same beast. Probably the most well known example is that of the Jurassic sauropods Brontosaurus and Apatosaurus. It was again Professor Marsh who had named and described both specimens but decades later they were declared to be one and the same dinosaur. Despite being a nearly complete skeleton compared to the Apatosaurus’s sparse sacrum and vertebrae, the poor Brontosaurus name was shelved by the scientific community because it had been named later.
As bad as the latest findings are for O. C. Marsh’s shrinking menagerie, they’re even worse for dinosaurs themselves.
"A major decline in diversity may have put the dinosaurs in a vulnerable state at the time when the large meteor struck the Earth at the end of the Cretaceous Period," Scannella said. "It may have been the combination of the two factors -- lower diversity and a major global catastrophe -- that resulted in the extinction of all the non-avian dinosaurs."
What I’d like to know is just how large did a young Triceratops get before his frill shape began to mature into an adult form? The literature all seems to list the Torosaurus as smaller in stature than Triceratops. Of course animals no matter what species come in all sorts of sizes, and this includes we humans (e.g. seventh graders can often tower over their middle-aged teachers). The Triceratops skeleton here at the Science Museum of Minnesota is considered the largest mounted specimen in the world. If that’s the case, and it is only an immature specimen, then he was one big boy.
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