Abraliopsis
Figure from Cephalopods: A World Guide (amzn/b&n/abe/pwll), by Mark Norman.
Pharyngula
Evolution, development, and random biological ejaculations from a godless liberal
Synergy! Ooblog leads me to a spectacular painting of carnotaurs mating (did they always get a flight of pterosaurs at the climax?), and then by way of The Two Percent Company, I found this enlightening poster of mammals mating (hey, how many of the first 20 have you done?)…with the unfortunate consequence of death by STD. Put two and two together, and what conclusion do we arrive at?
Dinosaurs didn’t use condoms.
So stop rubbing it in. Here’s an article about the superiority of the bird visual system: it doesn’t just have better acuity, it can process information faster. We’re adapted to a sedate stroll, they’re adapted to high speed aerobatics…and guess which one of us is crazy enough to pilot multi-ton vehicles at frightening speeds?
Maybe with a little butter and garlic.
This article makes a troubling point: if cephalopods are so smart, shouldn’t we feel some guilt about eating them?
I think I actually agree with some of the ethical issues raised, and probably should hesitate to kill and eat something like the octopus. However, it also commits the sin of lumping an extraordinarily diverse clade like the Cephalopoda into one poorly characterized gemisch. Yes, the Pacific octopus is a very clever beastie, but those schools of small, fast-breeding squid that get netted and chopped up for calamari? Not so much. The article makes a mistake comparable to highlighting the brilliance of Homo sapiens, and then arguing that we shouldn’t eat cows for fear of losing the next Shakespeare. If you want to make an ethical argument against the consumption of squid, that’s fair…but don’t do it by falsely concatenating all cephalopod species into an inaccurate classification of ‘smart, tool-using problem solvers’. It just isn’t true.
I also find this weird:
This evidence has so convinced officials on the Animal Procedures Committee (APC), the experimentation watchdog in the UK, that it has recommended to ministers that the law governing animal testing be amended so all cephalopods are given the same protection as animals.
So what have cephalopods been considered until now, mushrooms?
Now this is cool:
Just as sometimes humans are born with little tails, it seems that a few bottlenosed dolphins are born with vestiges of hindlimbs. The genetic toolbox for making limbs is all there, and sometimes it can get re-expressed, revealing these fascinating atavisms.
This odd marine worm, Xenoturbella bocki, is in the news right now, and I had to look it up in Pechenik’s Biology of the Invertebrates(amzn/b&n/abe/pwll) to remind myself of what it was. Here’s the complete entry:
Xenoturbella bocki
This marine worm, first described in 1949 as an acoel flatworm and later claimed as either an early metazoan offshoot or a primitive deuterostome, has recently been affiliated with primitive bivalve molluscs, based upon a study of gamete development (oogenesis) and an analysis of sequence data from both 18S rRNA and mitochondrial genes. Little is known about its reproductive mode, and developmental studies that might help to resolve the phylogenetic issues are just starting to be reported. A second species was described in 1999.
The animals are up to 4 cm long, vermiform (worm-shaped), and covered by locomotory cilia. They have no digestive tract, and indeed no organs at all. Their only conspicuous morphological feature, other than their cilia, is a statocyst for determining orientation. To date, they have been collected only off the coasts of Sweden and Scotland, in sediments at depths of 20 m to 100 m.
That’s it. Part of that is now known to be wrong: the data showing an affinity to the molluscs is an artifact, caused by the fact that it somehow eats bivalves, and partly digested clam material contaminated the samples. Otherwise, not much is known; I’ve found papers describing the presence of oocytes inside the animal, but no one as far as I know has actually observed its development. It’s a strange, mysterious blob of a worm.
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.
Strange things are found in the sea, like this mysterious gelatinous blob bobbing about in the Norwegian fjords.
On Oct. 1 Rudolf and his brother Erling were diving when he spotted the unusual object.
“It was 50-70 centimeters (19.5-27.5 inches) in diameter and looked like a huge beach ball. It was transparent but had a kind of thick, red cord in the middle. It was a bit science-fiction,” Svensen told newspaper Bergens Tidende’s web site.
It’s something cool: a large squid egg sac. Mmmmm…two-foot diameter ball of squid eggs.
