Pycnogonids really are fascinating animals and they deserve more attention. There’s a short news article on sea spiders that mentions their odd life style and their taxonomic awkwardness.
For over 100 years, scientists have been puzzling over how exactly to classify sea spiders or pycnogonids.
They crawl along the bottom of the sea floor, sometimes more than 6000 to 7000 metres down, where they live in the dark, feeding on slow-moving soft-bodied sponges and sea slugs.
The creatures are segmented and have an exoskeleton, which makes them an arthropod, the same grouping as crustaceans, insects, centipedes and spiders.
But they also have a very strange collection of features, including a unique feeding structure.
“They have a proboscis that’s like a straw that they insert into the animals and suck out the juices,” says Arango.
Such features make it difficult to fit them into any of the known groups of arthropods.
“They look like spiders, but they are not real spiders,” says Arango. “It’s been very hard to place them in a position within the tree of life.”
They really are hard to place—I’ve reviewed two articles on that subject, one that places them with the anomalocarids and another that groups them more conventionally, with the chelicerates (I’m going with that last one right now—patterns of Hox expression trump interpretations of innervation patterns, I think.)
I always thought that sea spiders were interesting in that “we don’t know much about them” sort of way.
When I was in grad school everyone asked me why I studied springtails. I used to joke that it was because sea spiders are too hard to collect.
“They look like spiders, but they are not real spiders,” says Arango.
Hmmph. Did he ever stop and think that perhaps it’s the land spiders that aren’t real spiders? If I were a sea spider, comments like this would really stick in my proboscis.
What does an analysis of their 16sRNA classify them as?
rRNA puts them in with the chelicerates but the bootstrap support isn’t that great.
Speaking of Pycnogonids, did you know that Errol Flynn’s father was Pycnogonid taxonomist? It’s true. And Errol, of course, was a swashbuckling actor in many pirate movies. So, indirectly, Pycnogonids are sacred to the FSM.
Well the closeup picture is definitely of a more menacing creature than the image of the person holding one. Spider or not, this thing would still drive women (and probably even me) batty at the sheer sight of one, should it emerge from behind a refrigerator or something.
Hey, I resent that comment! I think a *lot* of people in general have fears of creepy crawly things. I’m personally more afraid of those damn house centipedes and mosquitoes (allergic to bites) than spiders. Hell, this sea spider looks kinda cute to me.
Please forgive, for it was not my intent to offend. =)
Insects definitely drive me nuts more than they used to when I was a kid. The presence of an American Cockroach anwhere in my dwelling is a unique experience for me everytime I find them…unqiue != good. >=(
Other critters like small beetles and jumping spiders I just let be though. Having them around the house can be helpful, and they’re not particularly dirty, unlike roaches.
if one of these came out from behind my refrigerator i’d be so overcome with joy as to not be able to stand up straight. my neighbors would wonder who the childlike giggling was coming from in my house. my relatives would tire of pycnogonid stories (just as they tired of solfugid stories when i found one in my living room, especially after the crap “camel spider” pics were circulating the internets).
PZM, I’m really tired ofyour ad hox attacks on innervation. [/snark]
Given the discussion of things pynogonidan, some mention should be made of the passing of the grand old man (quite literally) of all things sea spiderish.
Joel Hedgpeth, died about two weeks ago.
He was one of the last of that group of biologists who really created the science of marine biology as it is now known. As with many of his contemporaries, such as Don Abbott, Gene Kozloff and Paul Illg, he not only was a noted expert in “his animals,” in this case pycnogonids, he a breadth of knowledge and interests largely unknown in most scientists today. Fluent in several languages, he also founded the Society for the Prevention of Progress, and wrote poetry (under the pseudonym, Jerome Tichenor).
As Jim Carlton stated, “Joel Hedgpeth lead a long and distinguished career as a scientist, environmentalist, writer, poet, historian, traveler, critic, and philosopher, and represented the grand tradition of an earlier generation who took great pride in the depth of their knowledge of the natural world.”
They crawl along the bottom of the sea floor, sometimes more than 6000 to 7000 metres down, where they live in the dark, feeding on slow-moving soft-bodied sponges and sea slugs.
this is not by any means, a complete description. I hope it wasn’t intended to be such?
pycnogonids live a wide variety of habitats. I used to collect them right off the docks in thickets of mussels when I was a kid.
True, these would be the smaller species (a couple of cm at most), but they are quite common in many intertidal zones as well as in the deep ocean. You can find the large ones in shallow waters in Antarctica, for example.
really, not a hard subject to obtain. If you live in Southern California, as i did, any trip to the rocky intertidal or harbor docks with a bucket can net you hundreds in an hour.
You can show em to your kids (you’ll hear lots of “ewww, gross!” most likely) and point to the kinds of research PZ documents here.
I can document the exact species you are likely to find in So. Cal., if anybody wants to go looking.
I think that my post was eaten so if this shows up twice I apologize…
I was just wondering what the difference between this type of probiscus and that of the butterfly or mosquito is. Aren’t they also more or less a straw like structure?
I’m sorry all. I’m not a biologist, just an engineer / Sci-Fi buff – so it’s pretty obvious to me that this is a Facehugger from the Alien movie series.
Tell me you’re dissecting one of these and I’ll keep my eye on you for possible chest-bursters. Don’t even pretend that something wants out of your chest ’cause I’d need serious psychiatric help afterwards.
Seeing one of these would definitely creep me out.
if one of these came out from behind my refrigerator i’d be so overcome with joy as to not be able to stand up straight. my neighbors would wonder who the childlike giggling was coming from in my house. my relatives would tire of pycnogonid stories (just as they tired of solfugid stories when i found one in my living room, especially after the crap “camel spider” pics were circulating the internets).
That’s like when I when I lifted a rock in my patio and saw what I thought was an earthworm — until I got closer and noticed the eyes and tiny little feet.
Sorry to hear about Joel Hedgpeth. In addition to all the things named, he was a Sherlockian, a member of one of the West Coast groups (the Scowrers & Molly Maguires, or the Trained Cormorants, I forget which). He wrote a piece identifying the worm unknown to science that apparently drove Isadora Persano mad.
Spoiler: Pogonophora. And this was before Black Smoker ecosystems.
Here’s an interesting article about these fascinating creatures…
http://www.seaslugforum.net/factsheet.cfm?base=pycnogon