Associated Press reports:
Dwarf Dinosaur Fossils Found in Germany; Their Size Was Tied to Island Life
By MALCOLM RITTER AP Science Writer
NEW YORK Jun 7, 2006 — When you think dinosaurs, you think big.
But German scientists say they’ve discovered a species that evolved into a dwarf, ending up only about one-third the size of its closest known relatives.
The fossils were of a four-legged plant-eater that 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.
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.
Scientists think that in an environment of limited resources, smaller body size becomes an advantage, and so captive populations shrink in body size over long periods of time.
The new creature is the best documented case of island dwarfism among dinosaurs, said P. Martin Sander, a paleontologist at the University of Bonn in Germany and lead author of a report in Thursday’s issue of the journal Nature.
The creature, dubbed Europasaurus holgeri, lived 154 million years ago in what is now northern Germany.
See also here.
Evolution of motion in archosaurs (including dinosaurs): here.