Snow white

 

From a distance, I looked into a tidepool and saw a snow white nudibranch.  When I got closer, I noticed the small brownish spots scattered across the upper surface.  My eyebrows furrowed.  My head tilted.  I recognized this species — a Ring-spotted Dorid (Diaulula sandiegensis) — but it looked different than every other individual I've seen on Bodega Head and in northern California.

Here are two examples. The first is from Bodega Head in July 2010:

 

Two individuals, side-by-side.  Note the beige or yellow background coloration, and that there are fewer, larger spots.

Below is a second example from Point Reyes in November 2013:

 

Three individuals, again with beige coloration and fewer, larger spots.

Now here's a picture of a Ring-spotted Dorid from Monterey in April 2013:

So...back to the individual I found today...the first picture of this post.  Which do you think it looks more like?  The nudibranchs from Bodega Head in 2010 (picture 2) and Point Reyes in 2013 (picture 3), or Monterey in 2013 (picture 4)?  

I think the individual I found today looks more like the individual from Monterey.  But I'm not sure what this means.  Is it possible that larvae drifted in the plankton from southern areas to Bodega Head this year?  Given the presence of warmer water along our coast during the summer and fall of 2014, this seems like a possibility.  Or is there something else going on?

Maybe it's just variation within the species, but it's puzzling that I haven't seen any individuals this pale or with this type of ring pattern on Bodega Head until this year.