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Thursday, July 13, 2017

Stauro-gazing


Not much time tonight, but I think you can see why I couldn't resist sharing this photo.  It's one of my favorites of the year!

If you've been following this blog for a while, you might have seen this species before, but it's been several years.  This is Manania gwilliami, a beautiful staurozoan. [Staurozoans are now a separate taxonomic class within the cnidarians.  Sometimes they're informally called stalked jellyfish.]  It was found locally today in the rocky intertidal zone.  We didn't measure it, but estimate it was ~12 mm long.

Here's the entire animal:



This individual had beautiful purple highlights.  Check out this close-up of two tentacle clusters:



When looking at the tentacles, I noticed some whitish pads at the base of some of the tentacles.  Here's one view:



After doing some research, I learned that these are adhesive pads.  It is hypothesized that when the staurozoan releases its pedal disc (the base of the stalk) from the substrate, it sometimes holds on with these pads while it reattaches.  Since I haven't been able to find many pictures of these interesting structures, here's one more image.  Look for the swollen white areas at the bases of the front three tentacles:



I'm sharing these staurozoan photos with you thanks to Hao Hao, one of Eric's summer students at the marine lab.  Her curious eyes spotted it attached to a blade of algae in the intertidal zone.  Thanks, Hao Hao!

P.S.  For an introduction to staurozoans, review the post called "Twinkle, twinkle, little stauro" from 12 November 2012.

3 comments:

Tessera said...

Wonderful!

Audrey Falconer said...

You might be interested in looking at my paper on these.

Falconer A. (2013). A Stalked Jellyfish Stenoscyphus inabai (Kishinouye, 1893) (Stauromedusae), found at The Jawbone, Port Phillip Bay, Victoria. The Victorian Naturalist 130 (5):202-207

I've also done a booklet on the species present in Victoria which can be downloaded from the Marine Research Group of the Field Naturalists Club of Victoria Facebook page.

I don't know if this link will work! https://www.facebook.com/groups/294926707198638/1931274213563871/

No need to post this comment if you don't want to.

Jackie Sones said...

Hi, Audrey!

Thanks so much! I'll try to find a copy of your paper. I'd be very interested in seeing your booklet, but I can't seem to access that link. (I don't have a Facebook account.) Is there another way to download the booklet?

Thanks for writing!

Jackie