About Apatosaurus louisae:
Apatosaurus grew up to 69 ft (21 m) long and ate plants. You may have heard it referred to by its scientifically incorrect name, Brontosaurus. This sauropod (long necked dinosaur) was discovered and named Apatosaurus, or "false lizard," because of its unbelievably large size. After Apatosaurus was named, other sauropod specimens were named Brontosaurus. It was later determined that both names actually referred to the same animal, Apatosaurus. In science the first used name is the official name so we use Apatosaurus exclusively. The species "louisae" was named after Andrew Carnegie's wife, Louise. Carnegie financed most of the excavations of the quarry at Dinosaur and had many of the specimens sent to Pittsburgh, Pennsylvania, where they still stand in the museum that bears his name.
Why is Apatosaurus louisae a superstar?
The "Discovery Bones" that led to the discovery of the Carnegie Quarry were tail vertebrae (back bones) of Apatosaurus louisae. This specimen, a nearly complete skeleton with a skull, became the type specimen of Apatosaurus louisae. This means that it was the first of its species ever found and scientifically described.
Like many sauropods and dinosaurs in general, Apatosaurus skulls are extremely rare. The skull bones are thin and easily crushed. Skulls are mostly hollow to hold soft tissues that cannot be preserved. Fine sediments compress the skull to flatten it the way you might step on an empty tin can. These skulls may be preserved, but some of the three-dimensional structure is lost.
The only Apatosaurus skull in the world was found in the Carnegie Quarry because the sand-sized sediment preserves bone in great detail without compressing it. Today a cast of the Apatosaurus skull is still on display with the rest of the specimen at the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania. The real skull is not on display due to the fragile nature of the bone.
Jurassic Fact: The body was discovered first and put on display at the Carnegie Museum without a head. After much debate, a Camarasaurus skull was incorrectly mounted to the specimen. Finally, in 1979 the proper skull was mounted.
For more information visit the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania where an Apatosaurus louisae from Dinosaur National Monument is on display. This is the only mounted skeleton of this species. A cast of the skull is also on display at the new Quarry Exhibit Hall.