meetings

Ann Gibbons reports on the AAPA meetings with a story about all the Homo erectus pelvis and stature papers ("Human ancestor caught in the midst of a makeover," subscription required). Research on the proportions of early Homo was the main event of the meetings, and Gibbons really caught the highlights of the story.

I wrote about body size in Homo erectus a few months ago, and much of the story follows from the basics I outlined there ("The changing height of Homo erectus"). But there I emphasized that the estimated adult height of KNM-WT 15000 was an outlier in a relatively small body size distribution.

What I didn't anticipate is that some interesting work might come along to question the tall adult stature estimate for that skeleton. Gibbons describes the work of Ronda Graves and colleagues, presented at the meetings:

Using intermediate growth rates, graduate student Ronda Graves of Stony Brook University in New York state calculated that Nariokotome Boy would have had less time than originally predicted to reach his adult height when he died. She estimated at the meeting that he would have reached 163 cm in height and 56 kg in weight as an adult—"shorter and wider" than previously thought.

This seems very short, at least when I first saw it. On reflection, Ohman and colleagues (2002) had provided a stature estimate at death of KNM-WT 15000, as only 147 cm, and they suggested it might have been as short as 141 cm. That's an awful lot shorter than had previously been estimated on the basis of regressions.

If Graves and colleagues are right about the lack of a human-like growth spurt, an additional 20 cm (8 inches) wouldn't be unusually small for an adult stature. Those stature estimates would put KNM-WT 15000 between the 50th and 90th percentiles for American 10-year-old boys, or between the 25th and 75th percentiles for 11-year-olds. By contrast, an adult stature of 163 would be around the 3rd percentile for adult American men. The assumptions about growth totally determine the outcome for adult height.

The credibility of the growth assumptions can only be tested by looking at other adult and juvenile remains. There is much more to say on this topic, but I'll point out one relevant comparison: The estimated stature of the adult skeleton from Dmanisi, including the complete D4167 femur and D3901 tibia, is between 145 and 166 cm. Graves' KNM-WT 15000 stature estimate is right within this range.

Meanwhile, there was a lot of disagreement about hips.

[Scott] Simpson and Linda Spurlock of the Cleveland Museum of Natural History realigned the pieces of Nariokotome Boy's pelvis, guided by a female H. erectus pelvis from Gona, Ethiopia, that Simpson reported 2 years ago (Science, 14 November 2008, p. 1089). They found that the widest measure from side to side on the boy's pelvis is 255 to 260 millimeters rather than 225 to 230 mm. This would give the boy an adult hip breadth of 295 to 301 mm rather than the 266 mm originally proposed, and would match those of the short, wide-hipped female from Gona, whose pelvic breadth was 288 mm. "H. erectus was not simply a small-brained modern human," says Simpson.

Simpson's reconstruction seemed reasonable, and it's actually not that big a difference -- roughly an inch and a half (3 cm) in bi-iliac breadth. The main differences were in the overall shape of the pelvis, being shorter with a more flaring iliac blade.

Gibbons describes the disputation that happened after Chris Ruff's presentation. Ruff has suggested that the Gona pelvis may not represent Homo -- that its broad proportions and small acetabula (hip sockets) suggest it may have belonged to an australopithecine (presumably, A. boisei).

Much of the disagreement comes down to the estimation of femur head diameter from acetabulum breadth -- Ruff (2010) gave an estimate of 32.6 mm, Simpson and colleagues estimated between 35 and 36 mm, based on a different method. What you would want is enough acetabula of both genera to be able to examine their variation directly. We don't have such a sample; what we have are a few acetabula and several femur heads. We have the additional problem that living people seem to have a different relation of femur head and acetabulum diameters than in other anthropoids, and it's not obvious which should be applied to early hominins.

I guess (in the relative absence of data) that this acetabulum diameter of the Gona pelvis was in the zone of overlap between Homo and Australopithecus. There's no question that later Homo -- say after 1 million years ago -- is substantially larger in acetabulum diameter, from every specimen so far described. But there are occasional small specimens of Homo even in the Middle Pleistocene. At 1.15 million years old, the Gona specimen is more than 300,000 years later than the last known occurrence of Australopithecus. The femur head that would fit the Gona acetabulum would be smaller than KNM-ER 1472 or D4167 from Dmanisi, both around 40 mm. At least one australopithecine femur head (AL 333-3) is that large, so the femur head diameter distributions do overlap. The STW 431 acetabulum diameter is a sliver larger than that of the Gona pelvis (Ruff 2010 makes it 3 mm bigger, but other workers have given a smaller estimate). SK 3155 may well be Homo and has a smaller acetabulum.

Of course, if we go as far as SK 3155, we have to consider the topic of the Malapa innominate. Can we tell small-bodied Homo from Australopithecus on the basis of pelvic morphology? Several people writing about the Gona pelvis have made it sound like a bigger version of Lucy's. But that's not really true. The australopithecine-like appearance comes from its breadth and consequent features, including the long pubes and flaring anterior ilia. The rest? Maybe there's something here for a clever anatomist.

UPDATE (2010-04-27): I have some e-mail about the last occurrence of A. boisei, which I wrote above was more than 300,000 years older than the Gona pelvis.

The most potent counterargument is Swartkrans Member 1, which has uranium-lead dates around 830,000 years ago, and has been placed by many workers around a million years ago. I actually hadn't been thinking of South Africa. But it is relevant, as the East African record between 1.4 and a million years ago may not be strong enough to argue that the last occurrence of A. boisei is really very close to the extinction time.

Meanwhile, there is OH 36, an ulna from Olduvai Gorge that may represent A. boisei. Since it's (obviously) not cranial, and is quite large and robust compared to postcranial remains that are associated with A. boisei, I've always been very skeptical of that assessment. If there's one feature of the ulna that actually has some phylogenetic importance in the Early Pleistocene, I figure it's size.

But given the current question about body size, that reason for skepticism may have receded in importance. On the other hand, OH 36 seems to represent a substantially bigger individual than the Gona pelvis, so maybe introducing robust australopithecines into the mix doesn't help anything.

Several things puzzle me. Even into Member 1 times, Swartkrans is dominated by A. robustus, with very little Homo. In East Africa, A. boisei is never quite so predominant in the hominin assemblage as the case in South Africa, but was nevertheless very common up to 1.5 million years ago. Did it persist much later? Was it cryptic from the point of view of the fossil record? Are the Swartkrans dates older than we think?

References:

Gibbons A. 2010. Human ancestor caught in the midst of a makeover. Science 328:413. doi:10.1126/science.328.5977.413

Ohman JC, Wood C, Wood B, Crompton RH, Günther MM, Yu L, Savage R, Wang W. 2002. Stature-at-death of KNM-WT 15000. Hum Evol 17:129-141. doi:10.1007/BF02436366

Ruff C. 2010. Body size and body shape in early hominins -- implications of the Gona pelvis. J Hum Evol (in press) doi:10.1016/j.jhevol.20 09.10.0 03

I'm just back from the physical anthropology meetings. What a lot of interesting things there were -- a few in the sessions, and many outside of them!

A few people asked me what I saw or heard that I would be writing up for the blog. I had to explain that a long time ago I decided not to blog about stuff I saw at conferences. It makes life easier in several ways -- I don't have to sit around taking notes, and people don't have to worry what they tell me.

Naturally, there are exceptions to every rule. Sometimes people have already published their stuff, or they're hoping to publicize work that won't be appearing in "embargo" journals. And sometimes there's stuff that isn't science, at least not directly, but deserves a record of some kind.

About these meetings, I want to write one thing -- these were outstanding for sharing casts of new things with the field at large. Darryl de Ruiter brought casts of many of the Malapa specimens, and made many opportunities to share them with everybody interested. Scott Simpson had brought a cast of his new reconstruction of the pelvis of the Nariokotome skeleton, and was showing it along with his poster about it.

For readers who don't usually study anatomy, I have to emphasize just how important it is to be able to look at a physical object. Descriptions and photos are, of course, necessary for publication, and they give a formalized account of anatomy. But the sheer size and three-dimensional appearance of a physical object carries tremendous information, not easily conveyed in words. I have worked with bone and fossils for many years, so that handling a cast allows me to place it next to thousands of objects in my tactile mental catalog. I have a much better understanding of those fossils now that I've gotten a chance to handle the casts, and that memory will stay with me.

I haven't seen such an availability of new casts at the meetings since 2001, when Maeve Leakey had casts of Kenyanthropus.

So I want to recognize how open and accessible those objects were at these meetings. These guys are real class acts, and their willingness to share and talk about the new fossils will advance the science. The quality of the reviews for their upcoming research papers will certainly be higher, since many of the potential reviewers will have a much greater familiarity with the fossils. Besides that, the mere opportunity to look at things along with a wide range of experts is really unique. I congratulate them.

Nature's editorial, "How to stop blogging" (which might sound like a self-help piece), takes a position on the conference blogging issue:

We are in the midst of a clash of conference-going cultures. Attendees who have taken to blogs and other social-media applications such as Twitter and Friend Feed will value the instantaneous communication of fact, conjecture and commentary as a way to network beyond badge-holders. Most researchers, in contrast, will focus on the science and ways to network with fellow attendees. If they are aware of social-networking applications, they are likely to regard them as distractions at best. At worst, they will fear them as tools to undermine and scoop, to release data not ready for consumption by anyone other than the trusted colleagues who bothered to make it to their talk or walk up to their poster and start asking questions.

Conference organizers are stuck in the middle. They want to let the world know that their meetings are worthwhile, and yet they also want to attract speakers presenting the newest and most cutting-edge findings. So how to protect speakers from having sensitive, unfinished or 'scoopable' work broadcast to the world?

There is a problem of attribution worth considering. Suppose some young blood watching a presentation has a great idea. Maybe it's an idea the presenter has already thought about, maybe not. Now, she blogs it. Now anyone can see how great (or obvious, or terrible) the idea is, and how it applies to the topic of the presentation. What are the presenter's obligations? As she prepares the publication, does she need to cite the blogger? Does she need to invite the blogger as a coauthor? Will reviewers know about the blogger's idea and demand that the manuscript be altered?

If we're going to open science conferences, we have to think about the meaning of authorship. Comment systems on scientific papers may help address the issue, by giving more opportunities for sharing ideas. But in the worst cases, a topic may draw such broad interest -- and at the bottom be seemingly so simple -- as to create a tangled mess of irresolvable ideas. Imagine crowdsourcing the hobbits....

No, I'm not doing that right now. Elizabeth Pennisi reports that some science writers are miffed about bloggers at scientific conferences:

In addition to reporting on genetic variation in a gene that is active in fast muscle fibers at The Biology of Genomes meeting, ["Genetic Future blogger Daniel] MacArthur wrote several on the spot blog posts covering advances discussed by the participants. Francis Collins also mentioned results on his new Web site.

A specialized Web-based news service, Genomeweb, complained. To attend CSHL meetings, reporters agree to obtain permission from a speaker before writing up any results. But MacArthur didn’t have to click that box when he registered and was free to report without getting any go-ahead. Several other participants were twittering, says CSHL meetings organizer David Stewart. “They weren’t held to the same standards” as the media, says Stewart.

CSHL is Cold Spring Harbor Laboratory, which puts on a roughly weekly series of conferences during the spring and fall on topics in biology. Organizers invite a relatively small number of researchers to present a plenary program, and a larger number of researchers and students pay fairly high fees to attend. It's a nice place, and although the fees run high, they're comparable to other conferences if you include the cost of the usual meeting hotel (since CSHL provides housing). But you can understand that a writer might want to be sure to get leads or background on several stories.

A non-attendee who followed blogs could pretty easily figure out several interesting stories and then make phone calls to the authors. It's not the same as networking in person, and it doesn't give the kind of context that conference attendance can give. But it's lot cheaper.

Dan MacArthur has posted his own reactions.

It's worth mentioning here that most of the dangers of live-blogging are (in my mind at least) generally over-stated. For instance, the risk of being scooped due to data posted on the web seems rather far-fetched given that most of the potential scoopers are already sitting in the audience watching the presentation. There is a fear that live-blogging distracts people from watching the seminar; I would argue in response that - given the number of people I see programming or working on their grant submission in genomics meetings - we should be grateful that live-bloggers are actually engaging directly with the material being presented.

An interesting conversation has emerged in MacArthur's comment section, and another at 2020 Science. Some commenters argue for openness at all costs, others that blogging a conference presentation is bad, bad, bad. And then there's the topic of tweeting. I'd be more likely to report conferences in haiku than on Twitter.

What do I think? Well, I often take notes at meetings, but rarely blog about the talks. That's not a hard policy, it's just the way my writing style works out for me. I hardly ever uncritically repeat what somebody may have said or written, I tell you what I think about it. Sure, sometimes my thoughts don't add much value, and sometimes it's my own misunderstandings that come out. But generally I want to explore why something looks wrong, or the assumptions that somebody missed. If I'm going to seriously engage with somebody's ideas, I need more to work with than a conference talk. It's too easy to make simple mistakes in a talk that you'd easily catch in a manuscript, and too hard to judge from a talk which mistakes are easily fixed and which may be fatal.

There are some posters and talks at every meeting that deserve more attention -- they tell a story that might not strike the casual observer as newsworthy, but that have real potential if told in the right way. Is it doing the authors a favor to blog about them? I can think of several better favors. Buttonhole a science writer and tell her why it's a story. Offer to interview the authors instead of just twittering their results. Always ask first before writing anything. How do you know that somebody who just saw the poster before you didn't tell the authors about some egregious error?

Over the last few years, I've noticed public meetings getting more and more scripted and boring. What a drag. There are lots of reasons for this, and blogging is not even close to the top of the list. But blogging and twittering and cell phone cameras are part of the technological changes that have helped to dull things. When you go to a talk that shows slides only in 50 millisecond increments, you know they're thinking about camera phones and bloggers taking notes. It's hard enough to keep from seeming like a jerk; technology doesn't seem to make it any easier.

Elizabeth Culotta reports from the Stony Brook hobbitrama:

The meeting was a rare chance for U.S. researchers to hear from the team that discovered the hobbits, which they officially call H. floresiensis. Lead excavator Thomas Sutikna of the National Research and Development Centre for Archaeology in Jakarta and Mike Morwood, now of the University of Wollongong in Australia, flew across the globe for the meeting, which gathered only those researchers who already accept H. floresiensis as a new species.

One piece of news: Matt Tocheri found another capitate among the bagged bone fragments:

The bone has the same peculiar and primitive configuration seen in the capitate of the main skeleton, suggesting that at least two individuals from Liang Bua have this oddly shaped wrist bone.

I think Culotta's short description gives a good flavor of the conference. The webcast version, which I mentioned earlier in the week hasn't shown up in the archive at Stony Brook. But two of the Richard Leakey symposia have video available (Link to archive), which might be interesting viewing.

I started one of them, and the Stony Brook provost introduces the symposium by noting that they wanted their series of symposia to include specialists with strong differences of opinion, with the hope of making progress toward defining the critical issues.

I guess somewhere along the way they decided to alter that strategy....

UPDATE (2008/4/15): The presentation was withdrawn from the meetings. I'm told that the information in the abstract is accurate, and that the withdrawal doesn't concern the science...

And no, the room wouldn't have been nearly big enough...

ORIGINAL POST:

Just flipping through the abstracts volume...this looks interesting:

New Homo erectus crania from Ethiopia

Simpson, S. W., Semaw S., Quade, J., Levin, N. E., Butler, R., Rogers, M. J., Holloway, R. L., Renne, P. R., Dupont-Nivet, G., Stout, D., Everett, M.

By the Early Pleistocene, members of the genus Homo were distributed throughout Africa and Asia, spreading into Europe by the Middle Pleistocene. As expected from such a widely distributed and long-lived species, variation in anatomical details is marked. This variation has fueled debate about the number of Early Pleistocene Homo species that existed and their relationship with modern humans. Here we report on two newly discovered hominid adult crania - one female and one male - dated to 1.5-1.7 My from the Busidima Formation, Gona Paleoanthropological Research Project area, Afar State, Ethiopia. An additional H. erectus cranial fragment (˜1.24My) is also reported. These crania are near contemporaries of specimens from Kenya, Tanzania, Republic of Georgia, and Southeast Asia and are attributable to Homo erectus. These fossils document a greater degree of brain size variation than previously known and allow a better accounting of the magnitude and character of cranial sexual dimorphism in size and shape.

New fossils, "greater degree of brain size variation," very cool. I hope they have a big enough room.

I'm going to be at the American Anthropological Association meetings this week, from Wednesday evening to Saturday morning. Maybe you'll see me!

I'll be giving a talk in Thursday's symposium in honor of my graduate advisor, Milford Wolpoff. The symposium runs from 1:45 to 5:30 on Thursday, and I'm scheduled about half-way through. The lineup includes some real stars of paleoanthropology, and it's sure to be the most interesting paleoanthropological stuff at the meetings:

BAS INVITED SESSION: "SAY WHAT YOU MEAN AND MEAN WHAT YOU SAY": PALEOANTHROPOLOGISTS HONOR THEIR MENTOR November 29, 1:45-5:30pm

Co-organizers: Karen Rosenberg and David Frayer
Chair: Eugene Giles

Participants

Presenter: Carol Ward
Paper Title: Pygmy arboreal midgets and the origins of hominin locomotion

Presenter: James Ahern
Paper Title: Variation among South African early hominins: the single species hypothesis revisited

Presenter: Adam Van Arsdale
Paper Title: Possible demographic implications for reduced adult mortality in Pleistocene human evolution

Presenter: Katarzyna Kaszycka
Paper Title: Dental variation and sexual dimorphism in the South African australopithecines

Presenter: Lynne Schepartz
Paper Title: Wolpoff in China: diplomacy to dental metrics

Presenter: David Frayer
Paper Title: New discoveries at Krapina: Evidence for ritual behavior beyond cannibalism and secondary burial

Presenter: John Hawks
Paper Title: Rapid selection, genetic reorganization and modern human origins

Presenter: Sang-Hee Lee
Paper Title: Exploring STET: a new method for examining variation and species

Presenter: Clark Larson
Paper Title: Life after the Pleistocene: health and adaptation in a new and dynamic world

Presenter: Karen Rosenberg
Paper Title: Wandering, working or wallowing; examining the link between limb bone geometry, activity patterns and human lifestyle

Presenter: Fred Smith
Paper Title: Aleš Hrdlicka, European Neandertals and Tennessee mountaineers: the role of environment in human evolution

Discussant: Alan Mann
Discussant: Milford Wolpoff

Be sure to come by and hear some of the real advancing frontier of paleoanthropology!

We've been watching this show on the SciFi channel, Mind Control, in which British "psychological illusionist" Derren Brown. Brown is sort of like a much less skeevy Criss Angel. Not that much less skeevy -- Brown is best-known for playing Russian roulette on TV. And like every aspiring mentalist, he's mastered that eyes-focused-somewhere-inside-your-skin look.

To tell you the truth, the show comes on after Flash Gordon, and, well, I'm a committed Flash Gordon nut.

Anyway, the beauty of the show is that Brown lets you in on the trick, at least some of the time, since the "trick" is really just the power of suggestion. With a highly rehearsed script including repeated cues, he can make people forget what they were thinking before, and to think what he wants instead.

I'm totally going to try this on my classes! Look out, students. Especially on evaluation day....

So in today's science section, the NY Times has a story by George Johnson, who got to sit in on Magic Day at the Consciousness meetings. It sounds pretty cool:

After two days of presentations by scientists and philosophers speculating on how the mind construes, and misconstrues, reality, we were hearing from the pros: James (The Amazing) Randi, Johnny Thompson (The Great Tomsoni), Mac King and Teller -- magicians who had intuitively mastered some of the lessons being learned in the laboratory about the limits of cognition and attention.

"This wasn't just a group of world-class performers," said Susana Martinez-Conde, a scientist at the Barrow Neurological Institute in Phoenix who studies optical illusions and what they say about the brain. "They were hand-picked because of their specific interest in the cognitive principles underlying the magic."

Page 2 of the story gums its way into the confusing topic of qualia. Now, Qualia Day in my biology of mind course would be a good one to try out the mind control -- that is, on the students who really can't be convinced that philosophy is fun.

This is a problem that's big and little at the same time -- from a certain perspective, nothing seems more central than qualia, and yet that centrality seems to have no observable effect on anything else. It's hard to avoid though -- because if you're going to discuss the mind from an evolutionary perspective, you have to lay out what kinds of things evolutionary biology is well-placed to explain. "Qualia" are among the few things that aren't (necessarily) on that list.

So stick to the front page if you're not interested -- and the last half of page 3, where the Amazing Randi gets a few words:

"Allow people to make assumptions and they will come away absolutely convinced that assumption was correct and that it represents fact," Mr. Randi said. "It's not necessarily so."

That's one of the reasons we used to love Jonathan Creek -- at least, until they got rid of Maddie. If your perception can be snookered by assumptions, then your logic can easily go with it.

The beauty of magic is that you know it's not possible, and yet your senses believe it anyway.

[Teller] left us with his definition of magic: "The theatrical linking of a cause with an effect that has no basis in physical reality, but that -- in our hearts -- ought to."

What's more amazing? That these scientists got a show from some of the best non-skeevy magicians in Vegas? Or that Teller talks?

I'm at the AAPA meetings in Philadelphia this week, which were preceded yesterday and today by the meetings of the Paleoanthropology Society.

There were several interesting papers given today, but I wanted to pass along the abstracts of the two pertaining to the Flores hominids:

"Allometric Scaling of Craniofacial Shape: Implications for the Liang Bua Hominins"

K. Baab, K. McNulty, and P. Brown

There has been considerable controversy concerning the taxonomy and evolutionary history of the hominin fossils recovered from the Indonesian island of Flores. One hypothesis is that these individuals were the result of insular dwarfing of H. erectus or a small bodied and as yet unknown hominin from the Asian mainland (e.g., Brown et al., 2004). Alternatively, some have claimed that LB 1 is a microcephalic modern human. This study will take a new approach to investigating the affinities of the Flores hominins by focusing on the three dimensional shape of the LB 1 craniofacial skeleton. To address the possibility of dwarfing in the evolutionary history of the Flores hominins, we also examined allometric scaling of craniofacial shape within the African apes and humans. As a first step, generalized Procrustes analysis was performed and principal components analysis (PCA) was used to explore the shape of the LB 1 neurocranium within a broad range of specimens representing both fossil and extant Homo species using geometric morphometric techniques. PCA indicated that the shape of the neurocranium was aligned most closely with H. erectus. A landmark set which also incorporated facial landmarks again showed similarities with H. erectus, particularly Asian H. erectus, but also with modern humans. The second set of analyses occurred in size-shape space, which, in addition to the Procrustes shape coordinates, also includes the logarithm of centroid size as an additional variable (Mitteroecker, 2004). By performing a PCA in size-shape space, we were also able to explore allometric patterns within and between Gorilla, Pan and Homo. While the apes, modern humans and archaic Homo all have separate trajectories, their slopes are quite similar. The position of LB 1 in size-shape space is compatible with its interpretation as a scaled down version of an archaic Homo species.

The second paper was much more interesting:

Morphological affinities of the wrist of Homo floresiensis

M. Tocheri, W. Jungers, S. Larson, C. Orr, T. Sutikna, Jatmiko, E. Saptomo, R. Due, T. Djubiantono, M. Morwood

The shape of the trapezoid in Homo sapiens is derived in comparison to the shape in other primates. Whereas the trapezoid of nonhuman primates is shaped like a pyramidal wedge (the narrow tip is palmar while the wide base is dorsal), that of H. sapiens is boot-shaped, resulting from a radio-ulnar and proximo-distal widening of the palmar half of the bone. The human trapezium, scaphoid, capitate, and second metacarpal base exhibit a derived complex of features that correlates with the distinctive shape of the trapezoid. Current paleontological evidence indicates that this derived complex of features evolved as early as 800,000 years ago and is a synapomorphy of H. sapiens and Homo neanderthalensis. The Homo floresiensis type specimen (LB1) includes a trapezoid, scaphoid, and capitate, all well-preserved and non-pathological. These small carpals display none of the aforementioned shared, derived features of H. sapiens and H. neanderthalensis. Rather, these bones are morphologically identical to the conditions seen in all African apes and in Australopithecus afarensis. The trapezoid is wedge-shaped with a small, dorsally-placed facet for the capitate and a large, triangular-shaped facet for the scaphoid, while the capitate and scaphoid exhibit the morphology that is typically correlated with the primitive trapezoid condition. As might be expected, the scaphoid and os centrale of H. floresiensis are completely fused, which is a synapomorphy of Gorilla, Pan, and Homo. The primitive carpal morphology of H. floresiensis is not consistent with hypotheses of a congenital or developmental abnormality afflicting a modern H. sapiens. Rather, the evidence is more consistent with hypotheses that H. floresiensis is descended from a hominin ancestor that migrated out of Africa prior to the evolution of the shared, derived carpal morphology characteristic of H. sapiens and H. neanderthalensis.

OK, after pasting that and fixing all the markup, I have to say that abstract drops entirely too many taxonomic names. But the basic point of the paper was that the wrist bones associated with the LB 1 skeleton don't look like modern humans. They look like the wrist bones of OH 7, which for these particular bones (trapezoid, scaphoid, and capitate) are similar to chimpanzees and other apes. Tocheri was fairly compelling in the description of the initial shape formation of the wrist bones prior to week 10 of fetal development; any genetic change that affected these shapes would have to be expressed very early. That would tend to make it unlikely that a single developmental change could have caused a modern human to have both the cranial form and the wrist morphology of LB 1.

There were some missing parts that should be fleshed out -- for instance, how much interpopulational variation is there in these bones in recent humans? The Neandertals overlapped with the modern human distribution, but there was no comparison of means.

Still, this may be a compelling argument for LB 1 not being modern, assuming the association of the wrist is good.

In the morning, I'm moderating a session with some more papers about the Flores hominids. I'll report anything interesting (including fights!).

UPDATE (4/2/2007): Sharp-eyed reader Brian Witte found an html error that spread a case of the italics across the site; many thanks for pointing it out!

In the last couple of days, I have had correspondence with a number of people about the wrist. Again, I should note that this is an area where a publication will really be required to evaluate the claims; particularly concerning developmental stability as a function of early differentiation.

I felt like Ryan Seacrest Thursday morning, introducing papers about LB 1. There's not really anything new to report, but there were a few dust-ups. The audience was standing room only, with the back of the room five ranks deep. The session had a mix of different talks, and a couple of authors had to cancel, which helped me keep things on schedule. We even had an extra ten minutes after Bob Eckhardt's talk for some discussion and questions.

A number of attendees let me know afterwards how much they enjoyed the session. I don't know whether that's true of all the authors, but I think I saw each of them smile at some point later in the week!

As for the talks themselves; I don't really want to give a detailed overview. I've seen lots of presentations during my time blogging, and I've never written a review of any of them. Many talks become papers, and the 15-minute format is really not sufficient to give the kinds of supporting details to support a scientific argument fully. It's just not fair to the research to critique it based on less than the published version.

But the abstracts are public, and there is certainly some interest in the contents of the talks, so I'll give some quick impressions of what was new. I did that earlier with Tocheri's paper about the wrist bones of LB 1.

Eckhardt and Dean Falk largely talked about details that were published within the last year. Falk presented some additional comparisons involving the microcephalic samples, mainly to argue that the juvenile specimens in that sample did not bias the endocast comparisons.

Lisa Nevell from GWU read a paper with many interesting allometric comparisons of LB 1 with recent humans and earlier hominids. This was nice work, and I hope to see it come out in publication. Still, the final sentence of the abstract says a lot:

These results are consistent with the taxonomic validity of Homo floresiensis, although they do not rule out the possibility that LB1 is pathological.

That ultimately is the bottom line of much work on LB 1, of course. Eckhardt pointed out that hundreds of conditions manifest with microcephaly as a symptom. Distinguishing a rare pathology from a rare pattern of evolution is an inconvenient problem.

The paper by Susan Larson and colleagues was read by Bill Jungers (Stony Brook). The conclusions of the presentation are summarized in the abstract's last paragraph:

We have examined the Liang Bua fossil material and find the analyses of the LB1 postcranial material by Richards (2006) and Jacob et al. (2006) to be incorrect on nearly all counts. Contrary to both Richards and Jacob and colleagues, both limb proportions and stature reconstruction for LB1 are completely outside ranges ever observed in modern humans, including the smallest "pygmoids." Previous studies have shown that muscularity cannot be deduced reliably from muscles scars. In addition, Jacob et al. (2006) exaggerate the degree of left/right asymmetry in LB1, and cortical bone thickness is perfectly normal and well within modern ranges.

It was after this paper that the questions became the most heated, as there are plainly differences in interpretation -- and in primary data -- between Jungers (and coauthors) and Eckhardt (and coauthors). It's really not possible to evaluate these differences fully without access to a published account.

I imagine that all the attendees probably thought much the same.

If you've come via a link about my current work, please welcome! I'm really not going to write about it here until our publication -- journals can be persnickety that way. But I am giving a talk about some aspects of the work today.

For folks in the San Diego / Southern California area, I'm going to be at a symposium at the Salk Institute this Friday and Saturday. The Friday portion is open to the public, and it includes some great speakers -- here's a schedule:

The Origin and Fate of Neanderthals

Salk Institute for Biological Studies
DeHoffmann Auditorium

Friday, November 3, 2006

2:00 - 2:10: Margaret Schoeninger, Opening remarks.

2:10 - 2:30: Svante Pääbo, "Neanderthal DNA"

2:30 - 2:50: John Hawks, "Combining morphology and population genetics"

2:50 - 3:10: Henry Harpending, "Molecular genetics of modern humans and Neanderthals"

3:10 - 3:30: Rachel Caspari, "Changes in life history patterns throughout the Paleolithic"

3:30 - 3:50: Steve Churchill, "The cost of life in ice age Europe"

3:50 - 4:10: John Speth, "Could Neanderthals chew gum and walk at the same time? A look at current archaeological ideas about the last 'archaic humans'"

4:10 - 4:30: Alison Brooks, "Palaeolithic tool industries"

This is really a stellar lineup for a public symposium, representing some of the most cutting edge research on Neandertals. That's one reason to go if you are in the neighborhood.

Another reason is moral support -- hey, I'm the junior participant by a lot! I need all the help I can get! It will help gird me up for the closed door session on Saturday!

Oh, and if you need one more reason? Remember all that stuff I haven't been blogging about? You know, the stuff that it stretches all logic to think that I wouldn't have some opinion about, but somehow the blog is completely silent?

Well....

Roberto Macchiarelli kindly sent along the web address for the webcast coverage of the "Lucy, 30 ans après" conference, which occurred earlier this summer in Aix en Provence. The conference program is also online. The videos require RealPlayer, so you'll want to get that if you want to watch them.

It's great that these talks are available on video for everyone to watch!

It's always interesting to go the AAA meetings. Many of the biological anthropologists who go are good friends of mine, and it is always good to see your friends. On the other hand, the meeting is so large that no one person can follow everything --- it's a conference by small subsets.

I was on an invited panel discussion of ethical issues in biological anthropology, particularly with relation to property. Those issues included data access, research transparency, ownership of identity, responsibilities to study populations and communities, and ownership of research materials. My part was to discuss concerns relating to genetic research on anthropological variation. Of course, there are many issues in this area touching on ethical concerns, including patents on genes from indigenous study populations, attaining informed consent from communities, and the current lack of recognition to a right to one's own genetic sequence. I briefly discussed the current use of comparative data on human genetic variation for "ancestry" testing. It's an important case of the scientific construction of identity. Some tests apply "scientific" methods that assign racial quanta to people on the basis of their alleles. These methods lie in potential conflict with both the actual pattern of genetic variation --- which does not fit the idea of discrete ancestral racial types --- and traditional conceptions of identity based on non-genetic knowledge.

It was very eye-opening to hear the discussions of different topics, from the study of habituated primate populations, to medical research in community-based research projects, to study of rare fossil remains. How do you study vulnerable populations or objects when studying them may result in their change or destruction? Michele Goldsmith explained some of the ways that habituating wild primates may lead to their ultimate doom --- habituated animals often become pests --- and that the nonhabituated population of mountain gorillas is diminishing. Alan Mann discussed the vulnerability of fossil remains to destruction, from molding, destructive sampling, and mere handling or measurement. Many other contributors brought forward a recurrent theme that it is difficult to find solutions to share data. Sharing may be essential to preserve what we study, but it cuts against research independence. And independence itself tends to proliferate research into new field sites, new methods of sampling fossil material, or new ways of capitalizing on knowledge. In this way, the disparate parts of biological anthropology all have connected ethical issues.

It was a very interesting interaction of different people, and the organizers (Trudy Turner and Rachel Caspari) want to bring it online for further commentary. Extending discussions like this one from a single time and audience to a larger group, with comments, might be a powerful way to build a community around the central concerns in the field.

Because being at the end of the alphabet gets you the last word.

Last weekend was the new Human Revolution conference at Cambridge: "Rethinking the Human Revolution: New Behavioural & Biological Perspectives on the Origins and Dispersal of Modern Humans".

The original "Human Revolution" conference was an important moment in the development and definition of the modern human origins problem. For one of the first times, archaeologists, paleontologists, and geneticists confronted the modern human origins problem with the specter of mtDNA variation hanging over them. The meeting was held in March, 1987 at Cambridge. The papers from the conference were split into two edited volumes. The major volume from the perspective of biology is The Human Revolution: Behavioral and Biological Perspectives on the Origins of Modern Humans, edited by Paul Mellars and Chris Stringer. This volume includes 17 papers on biological change (4 genetic), and 17 on archaeology and behavior (8 theoretical, 9 regional case studies).

Some of these papers constitute the best and most accessible published statements of the authors' theoretical frameworks -- especially some that have had a more limited role in the subsequent "Neandertal-modern human" debates.

I have spoken to several of the participants in that 1987 conference, who have diverse viewpoints on the interactions and effectiveness of the conference as a whole. At the least, it can be said that the event spurred the field toward the viewpoint that modern human origins was not merely a complex problem, but an actual stumbling block to any progress in understanding the evolution of human minds (comprising culture, language, sociality, and technology). There was certainly no consensus in the field then (any more than there is today) that archaic humans were substantially or completely replaced by "modern" humans. But once that logical extreme became a possibility, the behavioral, anatomical, and genetic records could not be interpreted without reference to this phylogenetic issue. If the mode of change was replacement, there would be no sense in interpreting the evolution of Neandertals as relevant to later people. Nor could it make sense to examine the pattern of behavioral change in Africa without reference to whether that pattern led to the replacement event.

So one view is that focusing on the problem actually intensified it. But this intensification has led to productive new research in African archaeology, in genetics, and in the chronology of Late Pleistocene Europe. In all three areas, the evidence has substantially changed during the past fifteen years. The phylogenetic problem remains a stumbling block, but in a very different way.

I'm not sure you would know any of this from the current "Revolution" conference. I have received several copies (thanks, readers!) of the extended abstracts of the current conference, which were embargoed before the conference and are not to be cited without permission. But I will give some of my impressions of the composition, based on the abstracts. I apologize for not being able to do the usual cite-and-critique; what I have to offer is a fairly general overview without specifics (except in one case). I have not been successful in finding any website associated with the conference; if anyone knows of one please let me know and I'll link it.

The new "Human Revolution" conference appears to have been much less biologically-oriented than the original. By my count, only twelve papers were primarily biological in focus, and of this number only four dealt in any substantial way with fossil evidence, three were molecular (2 mtDNA, 1 Y chromosome), one was linguistic, three dealt with social evolution and the brain, and one was devoted to species concepts.

Of course, several of the papers by working archaeologists had interesting things to say about the evolution of human behavior. There were twenty-nine such papers, ranging from site reports to theoretical synopses of the origin of culture. With more talks, the archaeological side appeared to have more diversity of viewpoints -- for example Francesco d'Errico is a notable contrarian to the hypothesis that behavioral modernity had a single origin in Africa, and he was included.

On the other hand, the geographical focus of the conference increased only marginally from the earlier Human Revolution meeting. The inclusion of more work in Africa is a valued addition, and reflects the increasing focus of the field on African MSA variability. But only two papers cover the world east of the Levant, none from South Asia or China. It seems to me that if "the human revolution" is really a valid pattern, that a simple test of its validity would be a truly global comparison.

A participant would have a better impression than I do, however, and if any report to me I'll be happy to relay their views.

The genetics have a certain "fiddling while Rome burns" flavor: the three papers are attempts to further refine the chronology of the "modern human dispersal", even as evidence from the vast majority of the genome now clearly indicates a substantially different picture of modern human origins. One imagines the work of the last Ptolemaic astronomers before they heard about Kepler's ellipses.

Considering the limited program, perhaps there were not available funds to bring in more speakers on fossil humans.

But at least there was Zilhão, who with the final abstract belies much of the preceding 70 pages. He has kindly given me permission to quote his abstract (with Erik Trinkaus) here. After laying out the "lines of reasoning" underlying the "Out of Africa with Complete Replacement" model, they respond thusly:

Recent research has exposed the empirical and logical flaws that cripple these arguments:

mtDNA is but a small fraction of the total human genome; when the nuclear genome is considered (hemoglobin beta locus or, recently, the patterns of polymorphism in the RRM2P4 pseudogene), there is ample evidence of the contribution of ancient non-African, hence by definition anatomically archaic, genetic lineages to extant humanity; that extant mtDNA lineages coalesce in Africa thus probably relates to differences in the size of the Pleistocene populations of the different continents;

the level of difference in the mtDNA of Neandertals and moderns is, by Primate standards, intra-specific, not inter-specific, and extant evidence of hybridization with viable, fertile offspring between close species, and even close genus, of monkeys and baboons precludes use of taxonomic arguments to assess past population dynamics;

the absence of Neandertal lineages in the sample of the five modern humans from ca.25 ka BP whose mtDNA has reportedly been obtained is in fact consistent, depending on a number of parameters, with levels of population admixture of up to 45%, i.e., approaching panmixia;

simulation studies concluding that levels of admixture greater than 0.1% would lead to observable percentages of Neandertal mtDNA lineages in extant Europeans use unrealistic models of population interaction and in fact simply arrive at conclusions that are already contained in the premises of the model used for the simulations;

if "fully symbolic sapiens behavior" is recognized in the archeological record by artifacts or features that carry a clear, exosomatic symbolic message, such as personal ornaments, then late Neandertals exhibited fully sapiens behavior; even if resulting from long-distance diffusion, the arrival of such innovations in southwestern France many millennia before any modern humans are documented in eastern Europe carries the implication that the process operated via the exchange networks of Neandertals, i.e., that we are dealing with the spread of a concept, and that is sufficient evidence for the existence of the cognitive capabilities required for its understanding and transmission;

the marked contrast apparent in the fossil record of the late twentieth century between the "early modern" and "classical Neandertal" trait-packages, suggesting population discontinuity, was an artifact of mistaking by "early modern" specimens that, in fact, were of much later age, most from the mid/late Holocene;

all the sufficiently complete, described specimens within ca.5000 years of contact currently known and directly dated (Oase and Muierii, Romania; Mladec, Czech Republic; Lagar Velho, Portugal) feature archaic/Neandertal traits that can only be explained by admixture between modern immigrants and local autochthonous populations.

One solution to a stumbling block is to assume it doesn't exist, that people who point it out are just being obstructionists, and that no right-thinking person could seriously hold such contrarian views. That attitude allows progress of a sort -- at least in theories -- and probably makes for a more pleasant post-conference reception. This is the "holding fingers in the ears and chanting 'la, la, la'" approach.

I for one welcome the stumbling blocks. They are the ways we learn things. They are sufficient now to teach us that the "human revolution" paradigm is wrong. Whatever the mode of biological change, it was more complex than replacement. Embrace the elephant in the room.

Now back from the meetings, I wanted to give my sincere thanks to all those who introduced themselves and had kind words about the weblog. I'm really glad to know that it's useful and is getting some people excited about human evolution. I keep track of the number of hits, but I can't say how much I appreciate the comments.

The e-mail rate from readers has increased recently, and I'm really happy about it. I usually take some time to answer thoughtfully, especially if it is a busy time at work or if I am out of town, or if the question can be turned into a post. So please don't be offended if I take a while to get back to you; my students actually are paying for my answers and I have to send theirs first.

I'll have some posts about things at the meetings that were interesting and thought-provoking, with a few topics that will take some research to put together good reviews. The Flores situation is beginning to induce schadenfreude; on that more below.

John Noble Wilford has an article in today's New York Times on the Neandertal conference. He focuses on Jim Ahern's (University of Wyoming) talk, which asked the essential question, "Did Neandertals and modern humans do it?"

I think it's a nice treatment, although basically a puff piece. The focus on Jim nicely captures the spirit of the weekend.