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Fossil Rises From its Grave
gokulpod writes "Scientific American reports that a family of animals known as Diatomyidae thought to have been dead for 11 million years has been discovered in Laos. From the article: 'Fossilized remnants of this group have been found throughout Asia with a distinctive jaw structure and molars. It represents a rare opportunity to compare assumptions derived from the fossil record and an actual living specimen to determine overall accuracy of the techniques involved. This discovery also provides a compelling argument for preservation efforts in Southeast Asia.'"
You don't have to find an animal previously believed extinct. There are millions of species around. Just put together case studies of known living animals. Then have a group unfamiliar with the species of interest try to predict its characteristics from genealogical family members.
This was done on a national geographic special several years ago. Individuals and Groups of knowledgeable biologists were given the same details they'd get from just the fossilized remains of different unique animals and given the task of reconstructing the live animal in behaviour, habitat and so on. One example was a kind of lemur I think from madagascar. The group were given a partial crushed fakely fossilized skeleton along with information on where it was supposedly found and some of the fossilized plant remains found with it in this scenario. Overall the groups working together came up with an accurate picture of the real animal where individuals had a success rate that varied from complete nonsense right up to accurate. Some other groups had bird types or reptiles and so on.
All good but for one thing. A large number of the species going extinct these days are not doing so as a result of Natural Selection wher-in they are out-competed and replaced in an ecological niche by some fitter successor. They are being killed off by us as we carpet-bomb the ecology. We don't replace any of the things we kill off (except for the large predators we offed early on in our rise to bad-assitude). Thus we are not a happy part of the happy circle of life. We're not pruning the evolutionary tree; we're chopping it down. -Pinkoir
Panda bears, polar bears, African elephants, all of the surviving Great Apes etc, fall into the former category. This makes the territory easy to explore. It also means that the region will likely be heavily surveyed by both corporations and environmentalists, each trying to win concessions to their perspective.
(Having said that, even well-studied populations aren't necessarily as well-understood as thought. At least one species of dolphin off the coast of New Zealand has turned out to really be two distinct species - drastically reducing the population of the first group. A group of Right Whales off the coast of Australia has also been demonstrated to really be multiple, genetically distinct species.)
Extremely remote locations aren't as well-studied. It's much harder to send undergraduates to remote islands around Papau New Guinea. No beer. Very remote locations are extremely difficult and expensive to study, so they generally aren't. This is where the bulk of "new species" and "rediscovered species" are found. These locations are generally under much less pressure, which means that amateur and semi-professional researchers are unlikely to take the time and effort to go - they're generally needed much more elsewhere.
Then, you've the problem of extremely small animals. The rediscovered woodpecker in North America is not the biggest bird on Earth, is highly mobile (duh!), blends in well with the environment, and is very probably terrified of people - the only people who go into that particular woodland being hunters. This rat-squirrel is likely smaller still, probably bleds in a lot better, and has had 11 million years of practice at running away.
Finally, numbers are very important. If you mis-count by 10 out of 1000 elephants, the number is basically still the same. If you mis-count by 10 the number of Yahtzee River dolphins (of which there are somewhere between 0 and 33 left), it is somewhat more significant. The scientists have not seen any of these rat-squirrels alive and only the one that was caught. As far as anyone is concerned, that may have been the last one alive - at present, we have no evidence to the contrary. If populations have been extremely low and highly localized, which is likely the case, then it was sheer chance that it was ever seen at all. See the story behind the discovery of the Wollemi Pine for other such discoveries.
(Numbers are absolutely critical when it comes to observing small species. It's easier to see one rhino from a mile off than ten dormice from a hundred feet, or a hundred fairy shrimp from five paces. As such, you need comparitively VAST numbers before you are likely to ever see anything at all.)
I don't completely trust the population counts (see my comments about genetically distinct species) but the observations I've seen would imply the counts may be far too high in some cases, NOT the other way round. There will unquestionably be more "living fossils" discovered over time, but the numbers will remain insignficant compared to the number of species that have genuinely been driven extinct - by "natural causes" or by human activity. This find ADDS to the urgency of efforts to save what there is, not the other way round.
(For a start, if its nearest cousin died off 11 million years ago, the population is likely genetically very similar, leaving it vulnerable to disease and genetic disorders. There is also no possibility of bolstering numbers through cross-breeding efforts - a rescue tactic used by some conservationists when "pure" populations are simply not possible any longer, as there's nothing left on Earth that will be even remotely close enough.)
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
I think the nagging assumption behind this question is, if the carbon dating is in fact accurate, then why hasn't this species evolved in the last 11 million years? Survival of the fittest certainly has eliminated a large majority of their population, and if the current species had no significant variation from an 11,000,000 year old fossil.. It doesn't seem the two theories co-habitate well in this situation.
Any fool can criticise, condemn, and complain, and most fools do. - Benjamin Franklin
argument for preservation efforts in Southeast Asia. And if you believe in Intellgent Design, it provides compelling argument that the earth is very young, or how could they have survived.
More to the point, why have crocodiles not changed much in 100 million years?
Perhaps it has something to do with the way creatures live. An organism which lives on the edge, so to speak, like a cheatah or a falcon, will experience selective pressure because there are so many ways for an individual in that species to fail at what they do.
Crocs just float into the water until their prey happens to come along: doesn't matter what really, then they eat it.
So maybe the answer is they they don't experience much selection pressure because of the (relatively) shit existance they live.
Another possibility is that the Crocodile lifestyle is a kind of local mininum for which they are well suited. Any change would make them less fit and their environment (creeks, estuaries, ditches) aren't going away any time soon.
I don't know about Diatomyidae, though.
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