Lucy’s legacy

As I’ve mentioned before, Lucy is going to be in Houston at the end of this week for an extended stay. This is not entirely a joyous occasion in the scientific community: many people, including Richard Leakey, are not happy that such a precious specimen has been subjected to the risks of travel. I sympathize. The bones of Lucy must be treated with the utmost care and regard, and any loss or damage would be an awful tragedy. However, there’s more to it than preserving an important fossil: Lucy is a touchstone to our past and is a symbol of the importance of our long history. We need to bring the ancient world to life for our citizens, and for not entirely rational reasons, people will want to see the real thing. I see that someone else shares my sentiment:

There is a wanton arrogance alive and kicking within the general scientific community. An arrogance that clings stubbornly to fact while at the same time stridently denying reality. And it pisses me the hell off. The facts in this case are clear: Lucy is one of the oldest hominid fossils ever discovered, and is very valuable for researchers. The reality of the situation is equally clear-cut, if a bit harder for the critics to swallow: Nobody gives a shit about replicas. Does it look the same? Sure. Can 99.9 percent of the population not tell the difference? You betcha. Does that matter? Not one iota. You see, for all the cranial capacity human beings have developed since little Lucy made do with a glob of gray matter the size of a key lime, we are not rational thinkers. Homo sapiens are, first and foremost, irrational and emotional.

I wouldn’t go so far as to call it arrogance, but there is a little selfishness to it, and most importantly, there’s a deep appreciation of the importance of that long-dead individual and a greater fear of its loss. What balances that fear, though, should be the recognition that other people could also stand to learn to love that tiny scrap of our long-past ancestry — the Lucy exhibit is an opportunity to teach.

Shouldn’t that be part of our mission? In addition to our own intimate learning of science, the task of sharing it with everyone else?

Clearly, bloggers need to take over science journalism

Aaargh. When will the media learn? National Geographic is running this ridiculous headline right now: New Fossil Ape May Shatter Human Evolution Theory, in which the reporter claims a discovery of some teeth could “demolish a working theory of human evolution.” It’s not true. Where is this nonsense coming from?

I read the article. It’s titled “A new species of great ape from the late Miocene epoch in Ethiopia.” The exciting news is that the “combined evidence suggests that Chororapithecus may be a basal member of the gorilla clade, and that the latter exhibited some amount of adaptive and phyletic diversity at around 10-11 Myr ago.” It concludes with a suggestion that we need to do more research in sediments appropriate to Miocene apes. There aren’t an exploding paradigms or revolutions suggested.

I read the associated news article in Nature. It’s titled “Oldest gorilla ages our joint ancestor.” It says that this discovery pushes back the time of divergence of the gorilla lineage from our own. This is just ordinary science.

Now read the blogs — they’re doing a much better job of evaluating this work than the traditional media. For one thing, they’re actually looking at it critically. Afarensis points out that these are only a few teeth, and it’s awfully thin grounds for a substantial revision of the timeline. John Hawks makes a similar point, but also highlights the fact that there is an unresolved problem — we need to reconcile paleontological and molecular dates. Even John Wilkins, a “mere” philosopher, weighs in sensibly that teeth are plastic characters in phylogeny, and deplores this peculiar media habit of taking a recalibration of a historical detail as a major reformulation of theory. All these discussions are sober and interested and most important of all, accurate.

The lesson is clear: when you see some wild and crazy claim of scientific revolutions and the demolition of long-held theories, go immediately to the science blogs for some clear-eyed sanity and informed evaluation from experts.

Lucky Houston gets Lucy

The state department has approved a visit from an eminent foreigner: a certain 3.2 million year old australopithicene is going to be at the Houston Museum of Natural Science from 31 August 2007 through 20 April 2008…and then she’s going on tour. Future locations haven’t been determined yet, but Minneapolis is nice. Chicago would be OK. I hope I get a chance to pay court on her.

Just a thought, but the creationists have got it all wrong. They think we worship Charles Darwin, but actually, if there are any objects of reverence among evolutionary biologists, it would be the evidence — the bones of Lucy, of Archaeopteryx, of Tiktaalik, the little trilobite in shale that I keep by my hand at my office desk.

It’s Big Bird! No, it’s Gigantoraptor!

This is Gigantoraptor erlianensis, a newly described oviraptorosaur from late Cretaceous of China. It’s a kind of nightmare version of Big Bird — it’s estimated to have weighed about 1400kg (1½ tons for non-metric Americans).

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Histological examination of the growth structure of the bones suggests that this fellow was a young adult, about 11 years old, and that they grew rapidly and reached nearly this size by the time they were 7. And since it is a young adult, there were probably bigger gigantoraptors running around. They also compared limb length to other dinosaurs, like the tyrannosaurs—gigantoraptor had longer, slimmer legs and was more of a runner than they were.

There’s no sign whether it was covered with bright yellow feathers.

Xu X, Tan Q, Wang J, Zhao X, Tan L (2007) A gigantic bird-like dinosaur from the Late Cretaceous of China. Nature advance online publication, 13 June 2007.

Stone soup; or, extracting protein fragments from T. rex bones

Science magazine has an article today on extracting and sequencing proteins from T. rex bones, and I’m already getting email from people wondering whether this is believable, whether it challenges the stated age of dinosaurs, whether this means we can soon reconstruct dinosaurs from preserved genetic information, and even a few creationists claiming this is proof of a young earth. Short answers: it looks like meticulous and entirely credible work to me, these fossil bones are really 68 million years old, and it represents a special case with limits to how far it can be expanded, so scratch “reassemble dinosaur from fragments” off your to-do list.

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Orthozanclus

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(click for larger image)
Reconstruction of O. reburrus by M. Collins. The precise arrangement of the anteriormost region remains somewhat conjectural.

Halkieriids are Cambrian animals that looked like slugs in scale mail; often when they died their scales, called sclerites, dissociated and scattered, and their sclerites represent a significant component of the small shelly fauna of the early Cambrian. They typically had their front and back ends capped with shells that resembled those we see in bivalve brachiopods. Wiwaxiids were also sluglike, but sported very prominent, long sclerites, and lacked the anterior and posterior shells; their exact position in the evolutionary tree has bounced about quite a bit, but some argument has made that they belong in the annelid ancestry, and that their sclerites are homologous to the bristly setae of worms. One simplistic picture of their relationship to modern forms was that the halkieriids expanded their shells and shed their scales to become molluscs, while the wiwaxiids minimized their armor to emphasize flexibility and became more wormlike. (Note that that is a very crude summary; relationships of these Cambrian groups to modern clades are extremely contentious. There’s a more accurate description of the relationships below.)

Now a new fossil has been found, Orthozanclus reburrus that unites the two into a larger clade, the halwaxiids. Like the halkieriids, it has an anterior shell (but not a posterior one), and like the wiwaxiids, it has long spiky sclerites. In some ways, this simplifies the relationships; it unites some problematic organisms into a single branch on the tree. The question now becomes where that branch is located—whether the halwaxiids belong in a separate phylum that split off from the lophophorate family tree after the molluscs, or whether the halwaxiids are a sister group to the molluscs.

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