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Monday, September 9, 2013

Gaze into my crystal bell

During a very short walk on 8 September we saw over 20 of these hydromedusae washed up on the outer beach:

This individual was ~9 cm across, but most were smaller in diameter.  This is Aequorea sp., sometimes known as the Crystal Jelly.  

Note its transparency and the hundreds of radial canals projecting outward towards the bell margin (see below).  The tentacles are missing, as is the mouth, probably because these medusae were tumbled in the surf.  But it's still a decent example of this distinctive species.

Aequorea are famously bioluminescent.  There's a nice description and images showing the bright green points of bioluminescence encircling the bell margin on the Bioluminescence Web Page.


David A. Hofmann said...

Hi Jackie,
Great find on the beach. On Aug.11, 2010 I found them alive at the Porto Bodega boat basin. I identified them as Many-ribbed Hydromedusa/Aequorea aequorea. My two photos are on Flickr.

David A. Hofmann said...

Hi Jackie,
Excuse my mistake. I identified the ones I saw at Porto Bodega as Aequorea victoria.

Jackie Sones said...

Hi, David!

Thanks for your comments and confirming that you've also observed Aequorea at Porto Bodega!

No worries about the species identification issue. It's actually a long-standing problem along the West Coast. There may be several species of Aequorea in the Northeast Pacific Ocean, but because there are few visual characters to separate them, the taxonomy hasn't been worked out (that I know of). I had heard that Mike Dawson (UC Merced) might be working on their genetics, so perhaps I'll check in with him to see if he learned anything about the different species that might be present in our region!

Claudia said...

Beautiful. Like blown glass.