Short dinosaur story reported by news@nature 1 June 2005, Nature vol. 435, p670, 2 June 2005 and Science News 18 June 2005.
One of the most distinctive features of sauropod dinosaurs (e.g. “Brontosaurus”) is a long neck that enabled them to reach into tall trees for food. Therefore, Oliver Rauhut of the Bavarian State Collection for Palaeontology and Geology and colleagues were surprised to find a sauropod fossil in South America that had a short neck.
The fossil, named Brachytrachelopan mesai is about 10m (33ft) long, with its neck being three-quarters the length of its body. This is considerably smaller than the largest sauropods which reached lengths of 30m and whose necks can be up to four times as long as their bodies.
The researchers found eight neck bones whose shape made it difficult for the animal to bend its neck upwards, so they suggest it fed on plants that grew from 1-2 metres above the ground. (Grass is not believed to have evolved until after the dinosaurs died out.)
The fossil is dated at 150 million years old, putting it in the late Jurassic period in the evolutionary timetable. The scientists who found it suggest it evolved rapidly in the middle Jurassic period from longer necked creatures because food was available on the ground and it did not need a long neck. “Nature tends to eliminate structures that are not needed for that reason,” commented Rauhut.
Paul Barrett, a palaeontologist at the Natural History Museum, London commented that B massai may not have had to compete with other grazing animals, such as ornithopods, which lived in other continents. “It looks like a dinosaur that is trying to reinvent itself. This fossil is telling us a lot about how these ecosystems evolved.”
Editorial Comment: It is all very well to make statements like “Nature tends to eliminate structures that are not needed” but this does not explain how being in a new environment with low growing food available changed the genes of an animal to produce different shaped neck bones.
It is also worth noting that the dinosaur’s head has not been found, so any claim that it had a short neck is based on the belief that it had the same number of neck bones as other similar dinosaurs – a reasonable assumption, but nevertheless not a known fact.
This story seems to be the opposite of the old and fallacious story of the giraffe evolving a long neck in order to eat tree leaves during a drought. However, like the giraffe, this new dinosaur, seems to be a unique creature well designed to survive in the environment it lived in, and as such, provides no evidence for evolution, but is wonderful evidence that evolution is such a flexible theory, it can evolve to fit all evidence.