Jul
26
2011

First "Brontosaurus" bones discovered

On this day (July 26) in 1879, in a desolate region of southeastern Wyoming, Arthur Lakes, a fossil collector engaged by Yale paleontologist O. C. Marsh to oversee his interests in the dinosaur bone beds at Como Bluff, wrote the following passage in his field journal:

"Men came back with report of discovery of very big bones at a spot between Quarries 8 and 9. Heavy thunderstorms hailstones fell the size of hens eggs. Telegraph wires broken.“

Arthur Lakes journal entry July 26, 1879.

Quarry 10 at Como Bluff, Wyoming: The bones of the famous "Brontosaurus excelsus" (Apatosaurus excelsus) were discovered here in 1879. The low ridge making up Como Bluff extends for about 7 miles, and has produced abundant dinosaur, reptile, fish and mammal fossils from the Late Jurassic period.
Quarry 10 at Como Bluff, Wyoming: The bones of the famous "Brontosaurus excelsus" (Apatosaurus excelsus) were discovered here in 1879. The low ridge making up Como Bluff extends for about 7 miles, and has produced abundant dinosaur, reptile, fish and mammal fossils from the Late Jurassic period.Courtesy Mark Ryan
The men mentioned were Bill Reed and Edward Ashley, two other Marsh workers at Como. The new dig site would soon be designated as Quarry 10, and the big bones those of a huge sauropod Marsh would later christen Brontosaurus excelsus. As most of you know by now, the genus name, Brontosaurus, which is Greek for “thunder lizard” would later be demoted to a mere synonym of the previously discovered Apatosaurus.

Apatosaurus vs Brontosaurus sacra: Figure illustrations created under the direction of O. C. Marsh show distinct differences between the sacra of Apatosaurus ajax (left) and "Brontosaurus excelsus" (right). Marsh thought they signified different genera, but didn't realize that the Apatosaurus represented a juvenile specimen and the Brontosaurus an adult one. A quarter-century after their discoveries, Elmer Riggs determined the two dinosaurs were of the same genus. As it grew in size, additional vertebrae of Apatosaurus fused in the sacrum to reinforce its pelvis.
Apatosaurus vs Brontosaurus sacra: Figure illustrations created under the direction of O. C. Marsh show distinct differences between the sacra of Apatosaurus ajax (left) and "Brontosaurus excelsus" (right). Marsh thought they signified different genera, but didn't realize that the Apatosaurus represented a juvenile specimen and the Brontosaurus an adult one. A quarter-century after their discoveries, Elmer Riggs determined the two dinosaurs were of the same genus. As it grew in size, additional vertebrae of Apatosaurus fused in the sacrum to reinforce its pelvis.Courtesy Mark Ryan
Brontosaurus’s species designation, excelsus, means “to exceed in number” and refers to the number of vertebrae in the dinosaur’s sacrum. Marsh’s Apatosaurus ajax had only three fused vertebrae in its sacrum, Brontosaurus had five. You can see what I mean in the side by side comparison of the figures Marsh had made of the fossil remains. That difference led the Yale professor to think he had two separate kinds of animals on his hands. But in truth, and as paleontologist Elmer Riggs declared in 1903, the two dinosaurs were actually the same genus. Although larger, the Apatosaurus, it turns out, was an immature specimen, while "Brontosaurus" was an adult one. It seems, as this very large type of dinosaur grew even larger, two more vertebrae fused into the sacrum to help reinforce the pelvis.

"Thunder Lizard" at the Peabody Museum: "Brontosaurus excelsus" (Apatosaurus excelsus) stands above other denizens discovered at Wyoming's Como Bluff. After its discovery its original name was determined to be scientifically invalid, it remains part of the Yale dinosaur's official record.
"Thunder Lizard" at the Peabody Museum: "Brontosaurus excelsus" (Apatosaurus excelsus) stands above other denizens discovered at Wyoming's Como Bluff. After its discovery its original name was determined to be scientifically invalid, it remains part of the Yale dinosaur's official record.Courtesy Mark Ryan
The sauropod first discovered on this date at Como Bluff is now known as Apatosaurus excelsus. But even though his extracted bones have stood quietly for 80 years at Yale’s Peabody Museum, the Thunder Lizard’s original name remains embedded in our culture. Since “Brontosaurus” is considered an invalid scientific name, it shouldn't be italicize when used but rather bracketed between quotation marks. Personally, I still prefer the name “Brontosaurus”, which Marsh used to describe the sound he imagined the huge dinosaur made while walking across the Jurassic terrain. And doesn’t the original name seem even more fitting since the great Thunder Lizard’s very first entry into human consciousness took place during a heavy thunderstorm?

SOURCES & LINKS
More about paleontologist O. C. Marsh
Apatosaurus ajax information
More about the Apatosaurus/”Brontosaurus” confusion
Apatosaurus (“Brontosaurus”) defined
"Brontosaurus" at Yale's Peabody Museum

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Anonymous's picture
Anonymous says:

yeah like 200 years ago

posted on Sun, 08/07/2011 - 2:52pm

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