In today's New York Times I have an article about the discovery of a vast graveyard of dodo fossils. The fossils date back an estimated 3,000 years. Dodo fossils are exquisitely rare, and so it's quite something to find an entire assemblage of them. But as the leader of the expedition that found them told me, that discovery alone would have been scientifically unimportant. What matters is the entire package. The scientists found fossils of lots of other animals and plants. It wasn't just the dodo that went extinct on the island of Mauritius. It was an entire ecosystem, and these fossils may help scientists understand how that ecosystem lived and breathed. Along with the article, I also talk about the discovery on the Science Times podcast this week (I come in at 8:40). And if you need more things dodo, check out the expedition blog.
Comments
Carl,
I find the term 'Fossil' as used in this article confusing. Forgive an electrical engineer for being out of his depth in biology - but I thought that fossilization only applied to matter preserved through mineralization. It was my understanding that this process took a lot longer than 3000 years.
Am I incorrect? Were these Dodo bones already mineralized, or partly mineralized? Can 'fossil' be applied to bones this early in the process of mineralization?
Posted by: calladus | July 4, 2006 2:39 PM
Calladus--
Your confusion is understandable. "What is a fossil?" is a bit like asking, "How old is old?"
Here's a passage that sums up the situation nicely, from the Audubon Guide to North American Fossils (p.13):
"Paleontologists disagree about how old a specimen must be before it can be called a fossil. Some require that it merely be older than historic time. Others stipulate that it must date from before the start of the geological epoch known as the Recent, or from at least 11,000 years ago. If a a plant or animal is extinct, its remains are usually considred a fossil even if they were buried only 100 years ago. If such remains are relatively recent and have not yet been mineralized, they are sometimes called subfossils."
Posted by: Carl Zimmer | July 5, 2006 11:26 AM
Thanks Carl!
Actually, your analogy is probably the explanation that I grasp best; "how old is old?"
The more 'vague' definition of fossil explains Dr. Mary Schweitzer calling demineralized tissue from a T-Rex bone 'fossil' where I would have just called it 'tissue'. I guess both are correct?
But this does undo a long held assumption of mine - that 'real' fossils were mineralized and that everything else was just 'well preserved.' I never asked myself at what point in the mineralization process does the subject become a fossil. Time for some reading!
Posted by: Calladus | July 5, 2006 12:17 PM
Also on the dodo, other extinct animals, and the Mauritius expedition: here.
Posted by: dearkitty | July 5, 2006 6:15 PM