Dwarf dinosaurs? It sounds like the old George Carlin joke about jumbo shrimp: two words that just don't go together. But fossils from northern Germany have revealed a dinosaur that evolved into a dwarf, ending up only about one-third the size of its closest known relatives, scientists report.
The four-legged plant-eater was no lap dog: It measured about 20 feet from its snout to the tip of its long tail and it weighed about a ton.
But next to its close evolutionary cousin Camarasaurus, a well-known beast that stretched some 59 feet long, this guy was a runt. What happened? The researchers say it's a case of island dwarfism, the tendency of big species to shrink over time when they find themselves on an island. It's well-known among mammals, as with fossil elephants only about 3 feet tall found in Sicily and elsewhere.