Hitchhiking amphipods

Hopefully this time the post will work!

Found this juvenile fied egg jellyfish, Phacellophoira camtschatika, a couple of weekends ago, in Howe Sound, near Vancouver, BC. Even when visibility really sucks, one can still find small treasures! Seems to have some hitchhikers along for the ride. Anyone know what amphipods these are? They are how I figured out what the jelly was, as they are normally as adults somewhat larger: this one is 3", they get up to two feet in diameter. My ID book on Pelagic inverts mentions symbiotic amphipods are usually present.

Cheers,

Marli

I think they're hyperiid amphipods. One called Phronima is pretty common in your area. There's a great picture of a hyperiid at http://mywebpages.comcast.net/kils/hyperia/hyperia1.htm Supposedly the screen "Alien" was modeled after a Phronima according to David Attenburgh in "The Blue Planet"

If you want to send me high-res files I can pass them around to 'pod people around here to see if they can verify the id. Cheers, Leslie

The Phronema I have seen had clear eyes but maybe this varies by sp.?

I saw two this past week in net hauls in the Gulf of Alaska done with a MOCNESS. Did not shoot them but have some on the ext HD at work from last year that I could dig up when I get back from a trip to this big Arctic meeting taking place in your neck of the woods.

Yup, I have heard they were the model for the aliens in the Aliens movies, easy to believe too.

Tom

I don't know if it's species or depth related. How deep were the MOCNESS samples? the ones I've collected using a night light from the Friday Harbor Lab boat dock were like Marli's & had big black eyes while other animals from midwater trawls had transparent eyes. I have no idea if they were the same species or not.

I like to think that the model for the Alien's eversible proboscis was a polychaete.

0 to 100m. I think of polychaetes as the model for the worms in the Dune books by Frank Herbert. The Phronema I have seen came from the open sea and look like the ones illustrated in the Open Sea double volume by Sir Allister Hardy, which is presently at the office too. I have not seen them yet (I now have a decade of observation) in tows done in Prince William Sound or from the inner Gulf of AK shelf, which appear to me to have strong coastal influence.

Tom

I'm not sure if it helps, but these had a distinct reddish area on what I assume are their backs.

Funny, when I got the photo back, Aliens are exactly what came to mind. Eewww.

Cheers,

Marli

Hi Marli -- Here's a best guess by a real 'pod person, Don Cadien...

"Just a guess, but the available detail in the photo suggests Hyperia

medusarum (O. Muller 1776), or Hyperia galba (Montagu 1815). Both species are known to occur on a variety of medusae, and are sufficiently similar in morphology and behavior that they cannot be separated based on evidence in the photo. At first I was leaning towards Vibilia, but the first antenna is not right for that genus.

By the way, if they are indeed Hyperia this isn't a joy-ride. The amphipods

feed on the tissues of the medusae."

Thanks for the info Leslie!

I love the Critter ID forum.

I love the Critter ID forum.

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So do I. I just wish there were more posts to play with!

Wow! Tissue eating "aliens" nonetheless

I must say that I love this forum too. There's always a lot of great stuff to learn in here.

Thanks guys!

David.

Yup, it is great. I often spend more time on this forum than taking photos!

Thanks, Leslie!

Guess this jelly won't be getting to the usual size.

Cheers,

Marli