Strange Crinoids and Underwater "Glass Tulips"

Check out this footage from a recent international expedition called the Collaborative East Antarctic Marine Census. Their mission is part of an effort to take stock of all the life in the world's ocean, but these creatures were filmed in the Antarctic Ocean (Southern Ocean). The bulbous, plantlike structures are called tunicates.

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anybody know what sort of rig was used to film this? it sure looked like a sled-type camera rig, which if true would crush my awe of the imagery even flatter than i suppose the benthic tunicates and sea spiders in the sled's path got squashed...

First, I am going to have to ask you to remove this post and you clearly violating the DSN Accord of 2007 which states in subsection 31b that

all topics related to the deep sea will be exclusively covered by DSN. Matters marine, but not deep sea, will be privy to DSN authors first who will then delegate topic to other blogs as they see fit

Second, the chains in the foreground seem to suggest a towed camera sledge

i don't know why those are reported as 'sea spiders', when they're very clearly free-swimming crinoids!

I second horgworm's comment. The media keep calling these "sea spiders", which is the common name for pycnogonids. Those are certainly not pycnogonids (though the Southern Ocean has some amazing pycnogonids) -- they are crinoids.

It may (or may not) be worth pointing out that tunicates are urochordates. They're filter feeders who are not much more than bags of water, but they're special because they're about our second closest relatives--you've got the vertebrates, then the cephalochordates, then the urochordates. (The cephalochordates and chordates probably evolved from a larvel urochordate that never grew up.)

Thanks to those that pointed out the swimming crinoid thing. I was wondering about those. Seemed to be too many "legs" for a sea spider. I was confused. (I don't study anything with a nucleus, so I suppose confusion is to be expected.)

Greg, how come the urochordates get all the fun? What if I never want to grow up. *whines* Can't I be a urochordate too?
The way my kids look at me sometimes you'd think I was. Of course I've been known to refer to them as "larvae."

Liesele, I may have been unclear--we vertebrates (i.e. chordates) are among the urochordate larva that never grew up. We get to have the wild dancing parties with our crazy limbs and heads and things while the stodgy urochordates stay home, stuck to the ocean floor sifting through gallons of sea water looking for bits of food.

I wrote a bit about this a while back in Talking Out of Our Asses. Probably it's not too inaccurate.

Don't worry, Greg, I get it, I do know we're chordates and all. I was just being silly. Again, blame the kids. Come to think of it how come they get to be all larval and stuff? Who said the pre-adolescents get to act like children anyway?
Incidentally, thanks Benny, I always loved tunicates since we were first introduced to them in high school. They're fascinating for lifeforms which appear so simple in a macro kind of way.