who-has-the-ct

There are three skulls from putative "hominins" that date to 3.5 million years or earlier. Every one of these skulls is known now from extensive reconstruction or correction for distortion in the original.

By itself, the extensive reconstruction might not be a problem. But as Tim White has repeatedly shown, the specialists on these crania actively and vociferously disagree about the basic anatomy due to problems reconstructing them. White's ongoing dispute about the skull of KNM-WT 40000 is a matter of public record, both in his initial 2003 article on the skull, and in Michael Balter's description of the recent Royal Society meeting*:

When the talk was thrown open for discussion, White took the microphone and began firing questions at Spoor about the degree of variation of the cheekbone position among specimens of A. afarensis and other hominin species. “We took that into account,” Spoor responded, “and I just showed you a graph” about it. “I didn’t ask you whether you took it into account; I asked you what it was,” White said. Spoor, clearly frustrated, told the audience that he had no vested interest in this debate. At that point, the session chair interrupted and invited everyone to break for coffee, but Spoor and White continued to debate between themselves for the next half-hour.

If KNM-WT 40000 were the worst case, that would be bad enough. But Ardi's skull has required reconstruction even more extensive than would be required for the Kenyanthropus holotype.

In their description of the Ardipithecus skull, Suwa and colleagues (2009) mainly present metrics taken from the CT reconstruction. The publication strikes me as remarkable in that it includes few photographs of the original fossil, and only one or two of the photos are in standard anatomical orientation. A substantial part of the CT reconstruction is based on a second individual (ARA-VP 1/500), of which no photographs are provided. For this, readers may refer back to the single rather poor photo in the 1994 description. Anatomical comparisons in the present paper are limited to visualizations of the CT reconstruction.

As I've written elsewhere, I think that Suwa and colleagues did a remarkable piece of reconstruction. But it is non-replicable. The CT-reconstruction is a composite of two specimens that includes mirror-imaged parts. A tremendous amount of work went into it, but without access to the component parts, it isn't possible to test or verify the assumptions underlying the present model.

Another striking thing about the Ardipithecus skull description is the lack of anatomical comparisons with relevant samples. I mentioned above that most of the figures involve metric comparisons -- many of them scaled to the cube root of endocranial volume -- which of course can only be taken on a small fraction of early hominin crania. That leaves out the most relevant specimens in the Hadar sample, including all the cranial specimens from AL 333. It leaves out most of the Sterkfontein collection.

And it brings us back -- again! -- to Kenyanthropus. Reading back through the paper, it's hard for me to believe that reviewers allowed Suwa and colleagues to publish on Ardi's skull without including any comparisons with KNM-WT 40000. It's the earliest complete skull of an undoubted hominin.

They're entitled to their opinion that the skull is distorted. I agree. But you can still compare most of its nonmetric features and put some reasonable bounds on its metrics. I mean, they included OH 5, for goodness sake -- which has nothing whatever to do with hominin origins. Including the comparisons wouldn't have changed much about the paper, although I'll point out that there's at least one derived feature of later hominins that KNM-WT 40000 and ARA-VP 1/500 both lack, and which isn't noted either by Suwa and colleagues (2009) or in the table presented by White and colleagues (2009).

So what should we do? We can't see the scans, no independent reconstructions are possible, and the people who can see the scans refuse to present comparisons of these three skulls that together represent the supposed origin of the hominin lineage.

AAAARRRRGGHHHH!

We need to set up multiple sets of independent reconstructors having a replicable go at these skulls. These are the three earliest hominin skulls. Every one of them is crushed in some weird way. It would be a credit to the science to document their reconstruction in nauseating monograph-level detail. They're scans, for goodness' sake -- there's absolutely no argument that access should be limited for any reason.

If I were running this, I would set up a graduate seminar devoted to putting them together, split among four universities, with results to be reported in a session at the meetings and monographically by e-publication. The issue is not whether we can obtain an exact representation of the original anatomy. The issue is whether we can reject hypotheses about that anatomy. Testing hypotheses requires us to survey the range of possible reconstructions and how they relate to the range of anatomical variation in living and extinct analogs. The more reconstructions, the better the testability.

At the moment, that testability isn't there. I trust the anatomical expertise of the people who made the models, but they're just single models with no assessment of the range of error. I've written about the importance of open access for these reconstructions already ("Open access and fossil reconstruction"). The points here just amplify that theme.

* As an aside, I wonder if the title of the Royal Society meeting ("The First 4 Million Years of Human Evolution") contemplated the possibility that there may have been only 4 million years of human evolution in total?

Putting science back in its proper place, Congress has taken up a bill to eliminate the requirement that publicly-funded research be freely accessible by the public. Open access watchdog Peter Suber writes:

The Fair Copyright Act ... would repeal the OA policy at the NIH and prevent similar OA policies at any federal agency. The bill has been referred to the House Judiciary Committee, where Conyers is Chairman, and where he has consolidated his power since last year by abolishing the Subcommittee on Courts, the Internet, and Intellectual Property. The Judiciary Committee does not specialize in science, science policy, or science funding, but copyright.

The premise of the bill, urged by the publishing lobby, is that the NIH policy somehow violates copyright law. The premise is false and cynical. If the NIH policy violated copyrights, or permitted the violation of copyrights, publishers wouldn't have to back this bill to amend US copyright law. Instead, they'd be in court where they'd already have a remedy.

I think the existing policy is not nearly as open as it should be. The free availability of most NIH-funded research after a year is very important; even scientists at most institutions may not have immediate access to research findings, since journal subscriptions have become so high. But even aside from the way that open access may improve the quality of research, I think it is essential that science remain an open process, with results open to the public.

Two years ago, I wrote about the problems of open access in paleoanthropology:

Most papers about new fossils are supported by data from scanning. A small proportion of these scans have been made available to paying professionals, or soon will be. Most are locked away, with no long-term prospect of ever being distributed. Today, none are openly available. Not a single scan of a hominid fossil can be obtained in the open, free of charge.

...[T]oday paleoanthropology faces a real credibility problem. A substantial majority in most of the world's countries believes that we are lying about human evolution. In the few nations that are exceptions, a substantial minority holds the same belief: human evolution is false. The human fossil record has been fabulated.

On Thursday, I had the privilege of doing an hour-long show on Wisconsin Public Radio, broadcasted statewide, about Darwin. It was a great experience, and I appreciated the chance to talk about the record of human evolution as well as Darwin's importance today. But it should be no surprise that one caller questioned the truth of the evidence about our evolution, claiming that scientists had proven that no transitional fossils exist.

I'm very fortunate in my topic. To answer this question I can immediately draw upon the rich hominid fossil record. And on Thursday, I was able to point to the newly sequenced 3 billion base pairs of the Neandertal genome.

But there's one important difference between those two kinds of evidence. Later this year, the Neandertal genome will be entirely public, so that anyone in the world with an Internet connection can download and examine it. Not so with the hominid fossil record. I can't point the public to any comparable source of raw information. With the Neandertal genome, by next year we may see high school science fair projects on Neandertal evolution. But do you think those kids will ever have a CT scan to work with?

Even on the more limited topic of open access publishing, more progress is needed. Some of the costs of making publications open access are now covered by grants, but not enough. Ultimately, open access depends on this funding. Scientists who do not have grant support may apply to have publication fees waived, but we need to be expanding public funding and requirements for open access publication, not contracting them.

A lot of scientists out there don't like the existing policy and want to roll it back. They would rather not have to make their data public. They have worked through conferences and meetings in the funding agencies to limit the impact of the current open access requirement.

Now, it looks possible that Congress will do the rolling back for them. That's at the behest of scientific publishers' interests, naturally. Public open access to the products of the public's money is nowhere near as important as Congress' open access to lobbyists' money.

(via Slashdot)