The radiation of deep sea octopuses

Last week’s Friday Cephalopod actually has an interesting story behind it. It was taken from a paper that describes the evolutionary radiation of deep-sea cephalopods.

First, a little background in geological history. Antarctica is a special case, in which a major shift in its climate occurred in the last 50 million years. If you look at a map, you’ll notice that Antarctica comes very close to the southern tip of South America; 50 million years ago, they were fully connected, and they only separated relatively recently due to continental drift.

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Weird creatures lurk in the depths

How odd — lots of people are sending me links to this video of a spindly-armed squid drifting through an oil-drilling site, but I’m pretty sure I posted this same video last year. I guess National Geographic just acquired rights to the footage.

It’s still a spectacular animal. And if that’s not enough, here’s a whole page of short clips of these Magnapinna squid in action.

Charismatic cephalofauna

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Christine Huffard sent me a note alerting me to the publication of her latest paper, and she thought I might be interested because I “seem to like cephalopods”. Hah. Well. I’ve noticed that Dr Huffard seems to have some small affection for the tentacled beasties herself.

The paper follows on an old tradition and an old problem. While people have no problem distinguishing human individuals, we have a tough time telling one individual animal from another. This perceptual difficulty complicates problems of studying variations in behavior or physiology, or monitoring numbers and behavior, in natural populations. One solution is tagging or marking the animals in some way, but that always has the risk of changing or harming the disturbed animals — non-invasive procedures are much preferred. This is an especially difficult problem with small animals, like zebrafish or small octopus; I’ve struggled myself with trying to track individual fish in experiments.

I came up with one solution, and Huffard et al. have come up with something similar: humans can be trained to recognize distinctive individual variations, and learn to identify single animals. In this paper, they describe a pattern of white pigmented regions that are consistent within single animals of the species Wunderpus photogenicus…and as you might guess, that is a great excuse to put together a collection of photographs of these aptly named animals.

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Uppity octopus

This is my kind of beast. Otto the octopus of the Sea Star aquarium in Coburg likes to cause trouble.

“We knew that he was bored as the aquarium is closed for winter, and at two feet, seven inches Otto had discovered he was big enough to swing onto the edge of his tank and shoot out a the 2000 Watt spot light above him with a carefully directed jet of water.”

…

“Once we saw him juggling the hermit crabs in his tank, another time he threw stones against the glass damaging it. And from time to time he completely re-arranges his tank to make it suit his own taste better – much to the distress of his fellow tank inhabitants.”

He was just expressing his cephalopodian nature militantly, I think.