So what if they want to chew your face off? They’re being the best Japanese Giant Hornets they can be.
Pharyngula
Evolution, development, and random biological ejaculations from a godless liberal
So what if they want to chew your face off? They’re being the best Japanese Giant Hornets they can be.
Something different this week: click the image and see David Gallo present a series of short video clips of cephalopods in action.
The capybara is the current champion for rodents of unusual size — it weighs about 60kg (about 130 pounds); another large rodent is the pakarana, which weighs about a quarter of that. Either one is far too much rattiness for most people to want hanging around.
Now there’s another king of the rodents: Josephoartigasia monesi, which is estimated to have tipped the scales at about 1000kg, over a ton. Don’t worry about getting bigger rat traps; these beasties have been extinct for perhaps 2 million years. I’ve put a few pictures from the paper describing this new species below the fold.
Hagfish are wonderful, beautiful, interesting animals. They are particularly attractive to evolutionary biologists because they have some very suggestive features that look primitive: they have no jaws, and they have no pectoral girdle or paired pectoral fins. They have very poorly developed eyes, no epiphysis, and only one semicircular canal; lampreys, while also lacking jaws, at least have good eyes and two semicircular canals. How hagfish fit into the evolutionary tree is still an open question, however.
How sweet: this octopus got a Mr Potato Head for Christmas, and now he won’t let anyone take it away.
Hasbro really must come out with a new line of Mr Potato Head features that includes beaks and suckers and tentacles, and then they’ll have the cephalopod market completely locked up.
Neurulation is a series of cell movements and shape changes, inductive interactions, and changes in gene expression that partitions tissues into a discrete neural tube. It is one of those early and significant morphogenetic events that define an important tissue, in this case the nervous system, and it’s also an event that can easily go wrong, producing relatively common birth defects like holoprosencephaly and spina bifida. Neurulation has been a somewhat messy phenomenon for comparative embryology, too, because there are not only subtle differences between different vertebrate lineages in precisely how they segregate the neural tissue, but there are also differences along the rostrocaudal axis of an individual organism. A recent review by Lowery and Sive, though, tidies up the confusion and pulls disparate stories together.
We’ve got a splendid new analysis of a southeast Asian artiodactyl from the Thewissen lab that reveals that these little deer-like animals are a sister taxon to whales — so this pushes our understanding of the ancestry of whales yet further back. Carl Zimmer has already described the essentials — I’ll just show a few pictures of the fossils.
