A Devonian lamprey, Priscomyzon

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Reconstruction of Priscomyzon in dorsal (top) and left lateral (bottom) views. b, Macropthalmia stage of Lampetra showing anterior location of orbit and smaller oral disc, both positioned in front of the branchial region. The total length of the specimen is 116 mm. Drawings in a and b are scaled to show equivalent head lengths: from anterior limit of the oral disc to rear of the branchial region. Horizontal bars indicate the anterior–posterior span of the oral disc in each species.

The life of a parasite must be a good one, and often successful; the creature at the top of the drawing above is a primitive lamprey from the Devonian, 360 million years ago, and the similarities with the modern lamprey (at the bottom) are amazing. It’s less eel-like and more tadpole-like than modern forms, but it has the same disc-shaped mouth specialized for latching on to the flank of its host, it has similar circumoral teeth for rasping through scales and skin for its blood meal, the same pharyngeal adaptations for a life spent clamped to a fish.

I’ve put a photo of the fossil and a cladogram below the fold.

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Lucy is going on tour

The remains of Lucy, the famous fossil australopithecine, are going to be touring the US for the next few years. Start lining up. It’s opening in Houston.

The six-year tour will also go to Washington, New York, Denver and Chicago. Officials said six other U.S. cities may be on the tour. But they would not release the names, saying all the details had not yet been ironed out.

Minneapolis, maybe? I hope? Otherwise I’m going to have to make a trip to Chicago.

No word yet on whether the Answers in Genesis museum near Cincinnati will be bidding on the exhibit.

A little pessimism about Extraterrestrial Intelligence

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Warren sent me link from The Indigestible, wondering if I was interested in these kinds of speculative questions about the existence of alien life. Why, yes I am…and even wrote something along the same lines a few years ago, coming to the same conclusions: I think intelligent extraterrestrials are unlikely.

My reasons are below the fold. Of course, I will retract my opinion immediately when Klaatu lands.

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Dissecting embryos from half a billion years ago

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There is a treasure trove in China: the well-preserved phosphatized embryos of the Doushantuo formation, a sampling of the developmental events in ancient metazoans between 551 and 635 million years ago. These are splendid specimens that give us a peek at some awesomely fragile organisms, and modern technology helps by giving us new tools, like x-ray computed tomography (CT), scanning electron microscopy (SEM), thin-section petrography, synchrotron X-ray tomographic microscopy (SRXTM), and computer-aided visualization, that allow us to dig into the fine detail inside these delicate specimens and display and manipulate the data. A new paper in Science describes a survey of a large collection of these embryos, probed with these new techniques, and rendered for our viewing pleasure…that is, we’ve got pretty pictures!

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Gogonasus andrewsae

Here’s another tetrapodomorph fish to consternate the creationists. These Devonian/Carboniferous animals just keep popping up to fill in the gaps in the evolutionary history of the tetrapod transition to the land—the last one was Tiktaalik.

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Skull in lateral view.

This lovely beastie is more fish than frog, as you can tell—it was a marine fish, 384-380 million years old, from Australia, and it was beautifully preserved. Gogonasus is not a new species, but the extraction and analysis of a new specimen has caused its position in the evolutionary tree to be reevaluated.

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Feminism is undermining human evolution!

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Human X (left) and Y (right) chromosomes

Did the internet get stupider while I was away this past week? I mean, it’s gratifying to my ego to imagine the average IQ of the virtual collective plummeting when I take some time off, but I really can’t believe I personally have this much influence. Maybe the kooks crept out in my absence, or maybe it was just the accumulation of a week’s worth of insanity that I saw in one painful blort when I was catching up.

What triggers such cynicism is the combination of Deepak Chopra, Oliver Curry, and now,
William Tucker. Tucker wrote a remarkably silly piece in the American Spectator in which he drew deeply faulty conclusions from human genetics to support a thesis rife with misogyny and foolish chauvinism on human evolution. It was like a piece on evolutionary psychology written by someone who didn’t know any genetics at all.

Hang on to your hats—we’re going to see a factoid from one magazine article balloon up into a declaration of the superiority of the male species (I use “species” here both ironically and mockingly).

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