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Sunday, November 10, 2013

Bells on the beach

Our last day in Oxnard, and we took one more very quick walk on the beach before the meeting started this morning.  Interestingly, today we found some siphonophores (at least parts of them) washing up on the sand.

Last April I posted about finding this siphonophore on Salmon Creek Beach, so you may want to review that entry, or read it now if you're new to the blog.

I feel pretty confident that we were finding the anterior nectophores (swimming bells) of Chelophyes appendiculata today.  Remember that they're ~1.5 cm long and look like little diamonds on the sand.  The anterior swimming bell has several pointed structures on one end that give it a jagged appearance (see below).

But we were also finding another swimming bell (at least that's what I think it is) that looked different, and I'm wondering if it's the posterior nectophore (see next image).  It wasn't quite as rigid, and came to one dramatic curved point at one end.

It might be helpful to review a diagram of the nectophores or swimming bells from the earlier post so you can imagine how they would be positioned on the living animal (see especially the left-hand illustration below).  Note that the top of the posterior nectophore is a curved point into which the siphosomal stem can be withdrawn.  [In the picture above, the swimming bell is being held upside down, only because that was the easiest way to photograph it at the time.]

Modified from Siphonophores and Velellids by Kirkpatrick and Pugh (1984) 

I have a lot to learn about siphonophores, but if was to fun to recognize these swimming bells on another beach at a different time of year!

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