|
Dinosaur paleontologists don't look for fossils simply because dinosaurs are cool. They want to solve evolutionary mysteries. Like all living things, dinosaurs form groups of species. You've got your long-necked sauropods, your head-shield-sporting ceratopsians, and so on. The distinctiveness of a group can make it difficult to determine how it evolved from an ancestor. Whales may be mammals (they nurse their young, for example), but they're all fish-shaped.
Some of the best clues to the origins of these groups come from transitional fossils, which are formed by species that evolved some, but not all, the traits that set a group of species off as a group. Transitional fossils can sometimes be very weird. My personal favorites are the early tetrapods (basically fish with fingers) and the early whales (whales with feet). But that's probably because they were the subject of my first book. Each year brings new transitional fossils to choose from. And now comes the latest addition: Guanlong wucaii, a forerunner of Tyrannosaurus rex.
| |
