Fossil daisy-chain

Blogging on Peer-Reviewed Research

Here’s a very strange fossil from the Chengjiang Lagerstätte, an early Cambrian fossil bed from 525 million years ago. It’s a collection of Waptia-like arthropods, nothing unusual there; these are ancient creatures that look rather like headless shrimp. What’s weird about it is the way the individuals are locked together in a daisy chain, with the telson (tail piece) of each individual stuck into the carapace of the animal behind. It’s not just a fluke, either — they have 22 fossil chains, and just one animal all by its lonesome.

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(Click for larger image)

Waptia-like arthropod, Lower Cambrian, Haikou, Yunnan. (A) Individual with twisted abdomen, part of chain, Yunnan Key Laboratory for Palaeontology, YKLP 11020a. (B) Chain, about 20 individuals, various dorsoventral-lateral orientations, composite image (joined at cpt/p arrow), YKLP 11020a and YKLP 11020b. (C) Individual linked to carapace behind, lateral view, part of chain of nine individuals, YKLP 11021. (D) Isolated individual, subventral view, YKLP 11019. (E to G) Reconstruction shown in dorsal, ventral, and right lateral views, respectively. Scale bars in (A), (C), and (D) indicate 1 mm; in (B) and (E) to (G), 5 mm. b, s, and t indicate bent, stretched, and telescoped individuals, respectively; cpt, counterpart; f, facing direction; p, part; and tw, twisted.

They do not look like animals that were constrained in a burrow, or that were crawling over the surface. Rather, they had been swimming together in a chain at death, and the whole chain fell to the sea bed, bending and kinking but still remaining firmly locked together.

Why were they doing this? My first thought was of sex; everyone knows how dragonflies and damselflies lock together for mating, but of course that would predict pairs of individuals, not 20 at a time. It also reminded me of the Drosophila mutant fruitless, in which male flies court other male flies, and they spontaneously form conga lines in the culture bottles. That’s also unlikely, since that kind of behavior doesn’t lead to a consistent pattern of successful reproduction, but maybe if these animals were hermaphroditic, it might work. It’s not a behavior that any modern arthropods show, however.

The authors consider the possibility it is a feeding strategy, but that’s even worse: they’re locked basically mouth to anus, which would mean the fellow at the end of the line gets a very unpleasant diet. They conclude that the most likely explanation is that this represents a migratory behavior, perhaps involved in daily vertical migration. It may have been that strings of these animals would link up and paddle together to move to new feeding sites, where they separated and dispersed until the time came to move elsewhere.


Hou X-G, Siveter DJ, Aldridge RJ, Siveter DJ (2008) Collective Behavior in an Early Cambrian Arthropod. Science 322(5899):224.

Please stop. You’re driving me insane!

DO NOT SEND ME ANY MORE REQUESTS TO CRASH THE PBS POLL ON SARAH PALIN. I am receiving over 50 email requests per day to do it, and there are a dozen comments every day mentioning it. You don’t see them because I’ve had to specifically add a filter to trash them automatically, and similarly, I’ve got an email filter that is killing all the messages direct to me. I know, the stupid poll has gone viral and there is email circulating all over the web asking people to vote on it, and everyone who sees it forwards it on to me, for some reason. It’s been done. It is a thoroughly hacked poll already. Please read my previous plea, This poll is an ex-poll, OK?.

At this rate, I might just have to put up a permanent, big, bold banner across the top of Pharyngula that tells people to throw that email about the PBS poll away.

Whoa. Hitchens endorses Obama!

On politics, Hitchens and I rarely agree…but this time he and I are singing in harmony. Obama is not a perfect candidate by any means, but McCain/Palin are a national disgrace, and there’s only one way rational people can vote.

It therefore seems to me that the Republican Party has invited not just defeat but discredit this year, and that both its nominees for the highest offices in the land should be decisively repudiated, along with any senators, congressmen, and governors who endorse them.

Throw all the rascals out, but be prepared to have to work hard to prod the Democrats into doing anything constructive with a majority.

VenomFangX vs. Thunderf00t

Ah, the weird, wild world of the interwebs, where one actually finds people calling themselves “VenomFangX” and “Thunderf00t” squaring off to do battle. VenomFangX is one of the lower denizens of Youtube, a creationist notorious for the arrogant confidence with which he states the ridiculous and ignorant. Thunderf00t is a calm rationalist and defender of science and evolution on Youtube, and they recently did battle.

VenomFangX, unable to actually outargue and outreason Thunderf00t, made a series of legal accusations, that Thunderf00t was violating copyright, and convinced Youtube to briefly yank his account. Thunderf00t shot those accusations down, and made a legal claim in reply, that abusing the copyright act had serious penalties associated with it, and demanded a public retraction and apology.

Thunderf00t won, and got VenomFangX to concede and read a detailed apology on camera, which is now on Youtube. I have to give it to VenomFangX, he actually managed to read it with a little dignity and about the same amount of sincerity you’ll find in his creationist videos — but I doubt that he has really learned anything from the episode, other than to be more careful about making actionable statements.

The 2008 IgNobels

Browse the IgNobel Awards and find your favorites. I rather liked the idea of ovulatory status affecting the earnings of lap dancers (although I’d like to know more about other factors that might influence performance), but the best was the title of the paper that won the literature prize: “You Bastard: A Narrative Exploration of the Experience of Indignation within Organizations.”

Why Evolution is True

I hope Jerry Coyne will forgive me that my frequent thought as I was reading his new book, Why Evolution Is True(amzn/b&n/abe/pwll) was, “Wow, this sure is easier to read than that other book.” That other book, of course, is Coyne and Orr’s comprehensive text on Speciation(amzn/b&n/abe/pwll), which is a technical and detailed survey of the subject in the title, and that I wouldn’t necessarily recommend to anyone who wasn’t at least a graduate student in biology. We all have our impressions colored by prior expectations, you know, and Jerry Coyne is that high-powered ecology and evolution guy at the University of Chicago whose papers I’ve read.

The new book is simple to summarize: just read the title. It’s aimed at a lay audience and answers the question of why biologists are so darned confident about the theory of evolution by going through a strong subset of the evidence. It begins with a discussion of what evolution is, then each subsequent chapter is organized around a class of evidence: fossils, embryology and historical accidents, biogeography, natural selection, sexual selection, speciation, and human evolution. If you want a straightforward primer in the experiments and observations that have made evolution the foundational principle of modern biology, this is the book for you.

Why Evolution is True makes an almost entirely positive case for evolution; it has an appropriate perspective on the current American conflict between science and religious fundamentalism that avoids dwelling on creationist nonsense, but still acknowledges where common misconceptions occur and where creationist PR, such as the Intelligent Design creationism fad, has raised stock objections. It’s a good strategy — the structure of this book is not dictated by creationist absurdities, but by good science, and creationism is simply noted where necessary and swatted down efficiently. It’s a more powerful tool for it, too — creationists can lie faster than anyone can rebut them, so the best strategy is to focus on the real evidence and force critics to address it directly.

You all really ought to pick up a copy of this book if you don’t already have a sound understanding of the basic lines of evidence for evolution (or, if you do, you could always get Speciation to get a little more depth). I recommend it unreservedly. Oh, except for one little reservation: it won’t be available until January. Go ahead and put it on your Amazon pre-order list, then.

Halloween in Toronto

So people want to know more about the Toronto visit…

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They’re charging for people to listen to me? Wow, I feel like Celine Dion now. You can get more information and order tickets at the CFI site.

I am a little uncomfortable with the hyperbole on the poster, though. Couldn’t they have said “world’s most famous atheist & science blogger from Morris, Minnesota”? Especially with Larry Moran right there in town, he is probably going to give me some grief over that line.

There are also some other things planned for Saturday, but I don’t have those details just yet. I know that the fabulous Skatje will be speaking in a panel or Q&A or something on that day, and I might be hovering around at a skeptics event around then, but it’s all a little vague right now. There will be stuff to do and opportunities to schmooze for those of you who’d rather go trick-or-treating Friday night.

The poster, by the way, is by Glendon Mellow, who even discusses his intent in creating it.

Where in the world is PZ Myers?

Since people have been asking about my travel schedule lately, here’s how I’m going to be spending my weekends:

Friday, 31 Oct-2 Nov: Toronto, ON
Friday, 7-9 Nov: Washington, DC
Thursday, 13-15 Nov: Kearney, NE
Wednesday, 19-22 Nov: Philadelphia, PA
Friday, 5-6 Dec: Orlando, FL

I’m hoping the visit to DC will be an especially joyous one.