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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Cool data!

Nick Matzke has
compiled all the data on hominin cranial capacities into a single chart:

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I think I can see a pattern there, can you? He also has data on body size and brain size over there, take a gander at it. It looks like a simple and obvious example of evolutionary change in our lineage, I think.

Alas, it only shows specimens older than 10,000 years. I’m sure that right around 6,000 years ago, there was a sudden, dramatic change as the deity injected a soul into those crania.

Palaeos reborn!

First I reported that Palaeos was lost, and then that it might be found, but now it looks like we can safely say it is being reborn. The old version of Palaeos has been at least partially restored, but the really important news is that a Palaeos wiki has been set up and people are working on reassembling old content and creating new information in a much more flexible format. If you’ve got some phylogenetic or palaeontological expertise, you might want to consider joining the Palaeos team and helping out with this big project.

3.3 million years old, 3 years old

Say hello to Selam, or DIK-1-1, a new and very well preserved member of the family discovered in Dikika, Ethiopia. She belongs to the species Australopithicus afarensis and is being called Lucy’s little sister.

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She was only a toddler when she died about 3.3 million years ago, and from the teeth the authors estimate that she was about 3 years old. Most of the skeleton is intact, but doesn’t seem to have yet been fully extracted from the matrix.

Some of the surprises: the hyoid bone is chimpanzee-like, and implies chimp-like vocalization abilities. She had a long way to go before she could have a conversation. The fingers are long and curved, and the scapula is more gorilla-like than ours; there is a suggestion of better arboreal ability than we have.

Alemseged Z, Spoor F, Kimbel WH, Bobe R, Geraads D, Reed D, Wynn JG (2006) A juvenile early hominin skeleton from Dikika, Ethiopia. Nature 443:296-301.

Palaeos found?

I got this email from Alan Kazlev, one of the main fellows working on the Palaeos website (a very useful paleontological resource), which I had previously reported as going offline. Plans are afoot to bring it back, and the answer seems to be to wikify it and build it anew, with a more distributed set of contributors. How Web 2.0! I’ve included the full email below the fold if you’d like more details.

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Palaeos lost?

Palaeos is gone! There is a brief note about being unable to support it any longer, and then poof, it’s offline. Martin Brazeau has a comment on it’s value; you can still see fragments of this great resource in google’s cache, but even that will fade too soon.

This is troubling, and it’s one of the worrisome aspects of using the net—there’s no sense of permanence. It would be good if someone were to step forward and at least archive all of the pages, but the essential feature of the Palaeos site was that it was continually maintained and updated to reflect current information, and that’s not something that can be supported without the dedication of much time and effort by someone knowledgeable in the subject.

Dinosaur lungs

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Next time you’re cutting up a fresh bird, try looking for the lungs. They’re about where you’d expect them to be, but they’re nestled up dorsally against the ribs and vertebrae, and they’re surprisingly small. If you think about it, the the thorax of a bird is a fairly rigid box, with that large sternal keel up front and short ribs—it’s a wonder that they are able to get enough air from those tiny organs with relatively little capability for expanding and contracting the chest.

How they do it is an amazing story. Birds have a radically effective respiratory system that works rather differently than ours, with multiple adaptations working together to improve their ability to take in oxygen. There is also a growing body of evidence that dinosaurs also shared many of these adaptations, tightening their link to birds and also making them potentially even more fierce—they were big, they were active, and their lungs were turbocharged.

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