There is a cool TED Talk [see video at the end] by dino-guru Jack Horner about why we never find "small" dinosaurs. It seems that paleontologists often find "new" species of dinosaurs when in reality, they really find a juvenile dino of a species that has already been discovered. Horner claims that this is due, in part, to the ego of men and their claim to fame in discovering and naming a species. His hypothesis about why many "different" dinosaurs are really just one dinosaur at various stages of its life is pretty compelling.
He shows how a Hypacrosaurus grew in a non-linear way and how its skull morphed into its adult shape. One technique he uses to prove his point is by examining the cross-section of a skull/bone to compare the bone density between various skulls. The "spongier" the skull, the more likely it was a juvenile that was still growing and Horner goes on to show that the famed Triceratops (Trike) was actually a younger Torosaurus. We see how the horns on the Trike start off curving upwards and in the latter stages, curves downwards. People thought at first that it was impossible that a Torosaurus was an older Trike because it has two hole in its frill and because it was bigger (pretty lame). Upon studying the bone density, Horners claims that they are the same dinosaur and found a transitional Trike with holes forming in its frill.
 |
Bone density says it all. All 3 skulls on the left are "spongy", even the Triceratops' 2m skull.
The Torosaurus has dense skull, indicating a mature specimen. |
 |
| Left: Skull bones change shape during growth Right: Transitional Trike with holes forming in its frill |
 |
| Nanotyrannus is actually a young T-Rex, despite having different # of teeth. Bone cross section on the right. |
 |
| Once thought to be 3 different dinos |
It's an interesting video to watch and learn about how things may not always be as them seem. Just because something looks a little different, doesn't mean it's not the same because the world ain't linear...
No comments:
Post a Comment