Organisms
pharyngula | July 5, 2007
A new squid has been caught near Hawaii — much is being made of the fact that it has eight arms instead of ten, but that doesn't seem like such a big deal to me, since we have the example of Taningia danae with a similar arrangement. It's more interesting that there is a preliminary assignment to the genus Mastigoteuthis, a curious and poorly understood group of cephalopods.
pharyngula | June 29, 2007Enteroctopus dofleini, the giant Pacific octopus
Figure from Cephalopods: A World Guide (amzn/b&n/abe/pwll), by Mark Norman.
pharyngula | June 24, 2007Jason Rosenhouse has dug into the details of the evo-devo chapter of Behe's The Edge of Evolution and found some clear examples of dishonest quote-mining (so what else is new, you may be thinking—it's what creationists do). I've warned you all before that when you see an ellipsis in a creationist quote, you ought to just assume that there's been something cut out that completely contradicts the point the creationist is making; Rosenhouse finds that Behe gets around that little red-flag problem by simply leaving out the ellipses.
I just want to expand a little bit on one point Behe mangles and…
pharyngula | June 22, 2007Nautilus belauensis
Figure from Cephalopods: A World Guide (amzn/b&n/abe/pwll), by Mark Norman.
pharyngula | June 15, 2007Octopus marginatus, in a coconut shell
And here it is, taking a walk while holding its shell with a few arms (good thing it has spares).
Figure from Cephalopods: A World Guide (amzn/b&n/abe/pwll), by Mark Norman.
pharyngula | June 13, 2007This is Gigantoraptor erlianensis, a newly described oviraptorosaur from late Cretaceous of China. It's a kind of nightmare version of Big Bird — it's estimated to have weighed about 1400kg (1½ tons for non-metric Americans).
Histological examination of the growth structure of the bones suggests that this fellow was a young adult, about 11 years old, and that they grew rapidly and reached nearly this size by the time they were 7. And since it is a young adult, there were probably bigger gigantoraptors running around. They also compared limb length to other dinosaurs, like the tyrannosaurs—…
pharyngula | June 11, 2007
Since I asked for it, and since so many were promptly forthcoming with a copy, I'd better give you a quick summary. Kubodera et al. have formally published their observations of the eight-armed deep sea squid, Taningia danae, that were in the news last February. There isn't much new information in the papers; it's all based on a handful of video observations of hunting squid in their native habitat, so it's more on the side of anecdote than anything else right now. It's still just plain cool.
That photo is of their video gear. It's a platform with lights and cameras that's lowered on a cable…
pharyngula | June 8, 2007Sepioloida lineolata
Figure from Cephalopods: A World Guide (amzn/b&n/abe/pwll), by Mark Norman.
pharyngula | June 7, 2007No, actually they don't — but they do have some proteins that are essential components of synapses, and it tells us something important about the evolution of the nervous system. A new paper by Sakarya et al. really isn't particularly revolutionary, but it is very interesting, and it does confirm something many of us suspected.
First, in case you don't know what I'm talking about, here's a synapse:
A synapse is a kind of gateway for the transmission of electrical impulses in the nervous system. What's portrayed above is the terminal of a generic neuron; electrical signals travel down from…
pharyngula | June 6, 2007Octopus vulgaris reacting to a diver (predator).
The initial change from camouflaged to conspicuous takes only milliseconds due to direct neural control of the skin. Full expression of the threat display (right) is two seconds. Video frame rate is 30 frames per second. Watch the video clip.
Everyone here is familiar with the incredible ability of cephalopods to change their appearance, right? If you aren't, review your cuttlefish anatomy and watch this video. A few frames from the video are shown on the right.
This is an amazing ability, and the question is how do they do it? Roger Hanlon has…
pharyngula | June 2, 2007In chapter 14 of the Origin of Species, Darwin wondered about the whole process of metamorphosis. Some species undergo radical transformations from embryo to adult, passing through larval stages that are very different from the adult, while others proceed directly to the adult form. This process of metamorphosis is of great interest to both developmental and evolutionary biologists, because what we see are major transitions in form not over long periods of time, but within a single generation.
We are so much accustomed to see a difference in structure between
the embryo and the adult, that we…
pharyngula | June 1, 2007Needle cuttlefish, Sepia aculeata, front view at night, Dumaguete, Negros Island, Philippines
(via ArteSub, where you can find a whole collection of underwater photography)
pharyngula | May 29, 2007A good way to recover from the fra…fra…frammmm… that topic is to go watch the freaky frogs. If it's late at night and dark where you are, though, don't watch them. The first one will creep you out, and the second one will deliver the coup de grace; you won't be able to get to sleep for fear of the amphibians outside your window.
pharyngula | May 26, 2007It's a friend with a face full of necrotizing venom, which just makes him a little more special, I think. Anyway, it's a good story about a responsible, rational reaction to finding a brown recluse spider in the house, and the little guy is so darned cute, too.
pharyngula | May 25, 2007Argonauta nodosa
Figure from Cephalopods: A World Guide (amzn/b&n/abe/pwll), by Mark Norman.
pharyngula | May 23, 2007Add hammerhead sharks to your list of animals that don't need males. A captive bonnethead female in Nebraska gave birth in 2001, and genetic testing has revealed that it was produced by parthenogenesis. In a way, this isn't a surprise: I could have told her that Nebraska is no place for a self-respecting shark to look for a boyfriend.
Parthenogenesis had been suspected, because the shark had been isolated from males for at least 3 years, and because she lacked the obvious bite marks that result from shark sex (which is another reason a lady shark might not want to have anything to do with…
pharyngula | May 22, 2007Leave it to Susie Bright to connect a review of a spectacular book about deep sea organisms to sex toys.
I'm going to get the book myself, but now I'm going to have a whole 'nother view of its contents. Oh, wait…actually, maybe not.
pharyngula | May 22, 2007Here are three animals. If you had to classify them on the basis of this superficial glimpse, which two would you guess were most closely related to each other, and which one would be most distant from the others?
On the left is a urochordate, an ascidian, a sessile, filter-feeding blob that is anchored to rocks or pilings and sucks in sea water to extract microorganismal meals. In the middle is a cephalochordate, Amphioxus, also a filter feeder, but capable of free swimming. On the right are some fish larvae. All are members of the chordata, the deuterostomes with notochords. If you'd…