Orange and pink

 

Sunset from Bodega Head, 14 November 2012

The oranges and pinks in the sunset photo reminded me of this nudibranch crawling on coralline algae photographed the day before (13 November 2012).

 

This is a Spotted Triopha (Triopha maculata).  Note the dark brown background color, bright orange projections on the head and back, and bright orange gills (ruffled structure about 2/3 of the way back from the head).

This nudibranch was ~3 cm long.  Smaller individuals may appear dominantly orange and larger individuals are often yellow, but all of them show the spots.  Interestingly, Morris, Abbott and Haderlie (1980) note that the color pattern resembles orange/brown kelp blades with white bryozoan colonies.  (Spotted Triophas are often found on kelp and they eat bryozoans.)

I don't have a photo of kelp with bryozoans, but I do have one of kelp with white spirorbid tube worms (next photo).  To my eye, the nudibranch spots also resemble these coiled worm tubes!

 

Here's a different individual, this one was discovered at Duxbury Reef in Bolinas in November 2007.  (The image below is posed; we placed the nudibranch in an empty mussel shell filled with seawater for the photo.)