Thursday, April 19, 2012

Is this a tunicate?

I have spent hours in the last couple of days, trying to identify the last animals I found in the clamshell. All to no avail; I am still as confused as I was before I started.

After all the creeping and scrambling beasties had been washed out and transferred to the aquarium, what remained were the little acorn barnacles, and, in the bottom of the shell, a colony of little brown jugs.

They're shaped like those little brown glass whiskey bottles I find in antique stores.

One opening at the top, curved "wings". The small barnacles give an idea of their size; maybe up to 1 cm. tall.

These look to me like solitary or social tunicates, but I can't find any that look like this. And tunicates are basically a living filter system, with two siphons, an intake and an outlet; most of these seem to have only one siphon. Where is the other one?

Removed from the shell, they stand up on my foam base. In this photo, it looks like two of them have the outlet siphon, as well.

A single animal, on its jelly base.

In the second photo, one has a snail crawling near the siphon. Here it is, greatly magnified.

It looks like a trophon snail.

I keep thinking of another species of tunicate, and going off hopefully to investigate. Everything is similar; nothing matches. Help!

17 comments:

  1. I'm going to FB this , and tag my daughter, who is an invertebrate marine biologist. She might have an answer for you.

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  2. It actually looks like snail egg cases. I would even suggest that that snail that you found may have hatched from it. (Hard to tell without relative scale)

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  3. Thanks, Brine Queen! The snail was about 1/4 the length of the egg case.

    I hadn't thought of egg cases; most of the eggs I've seen come in strings or clumps of "tapioca" balls, or in a mass of jelly.

    I'll investigate further. I don't find many sites or books where eggs are co-ordinated with their adults; do you know of any good links?

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  4. I can't find details either. I can narrow it down to Murex, but not to Trophon. While I can find similar images online, the closest they identify is "murex". I'm guessing that you'll probably need to go to a good print guide. The other person you might ask is Rick McPherson. I'll put him in touch via FB as well.

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  5. Thanks, Kate. I've found similar egg cases in a variety of Murex snails, but none just the same. I'll keep on looking; at least we seem to be on the right track.

    I don't know Rick; I'll watch for a comment from him.

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  6. RIck just commented on my timeline:

    Rick MacPherson They seem remarkably similar to a dog whelk egg mass. Tall, translucent "bottles". I don't think tunicate, no split or dual siphon. That's the best I can manage at the moment. Cool though!

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  7. Anonymous5:30 pm

    Any answer? I have something alive in a rock that looks the same shape, but its maroon in color. Its sensitive to light changes and will pull itself in the rock

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  8. Anonymous; the general consensus is that it's some kind of snail egg case. I'd like to see photos of what you have.

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  9. Anonymous6:29 pm

    I got two pics, sorry for the bad quality. These "snail eggs" are the closest thing i have seen to the shape of my mystery critter.
    http://s1153.photobucket.com/albums/p507/westendstp/

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  10. Anonymous; Is this in your aquarium? Where did it come from, and how big is it? It looks familiar, but from those photos, I can't decide why.

    You say it withdraws when it's in the light. Does it have a hole in the rock, or just shrink into itself?

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  11. Anonymous9:17 pm

    Yes it is in my aquarium, it came with a live rock from a local pet store. The rock is pretty smooth, not hole ridden like other live rock i have seen. It is in a hole, and it can completely disappear if it wants to. It's probably an inch and a half when long when fully protruded from the rock. It seems to drop waste from between the wings as pictured. The back of the rock also has a hole where the thinner part it sticks outs.

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  12. Sounds interesting! I know it's difficult, but it would be good if you could get more photos of your critter. I had better luck with aquarium photos using lights from various angles and setting the white balance under them before shooting. And taking lots and lots of photos and dumping most of them.

    If you can get back to the local store, maybe you can find out where they bring the live rock from. Location often helps with identification.

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  13. I forgot; does it change in any way beyond stretching and shrinking? Does the shape or colour change?

    How long have you had it?

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  14. Anonymous6:32 am

    Ill try to get better pictures later today. We have had it for about a month and a half. It can pull itself in very fast when startled. The tube at the end gets wider at times. I assume this when it is feeding because during this time small particles will roll down between the wings. The color says the same, a translucent maroon marble like pattern. The shape is so much like your pictures if you turn them upside down.

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  15. This gets more interesting with each detail you add. I think, if you get any clearer photos, I'll do a blog post, to get other people working on the id. And there are a couple of experts I'll contact directly.

    Where are you located? What else is in your aquarium? What do you feed them? I'm wondering about your critter's food: live, plankton, algae, etc.

    There may be a problem taking photos if it shrinks back into the rock under light. I would suggest setting up everything, lights, camera, etc, then turning the lights off for a while. Then, manually focus under dim light, switch on all the lights at once, and snap your photo instantly, to catch an extended critter. Would that work? You might need a helper for this.

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  16. I think I see a faint suggestion of tentacles on your first photo. Can you see these with the naked eye?

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