Granulina margaritula the “Little Pearl” is a prosobranch gastropod belonging to the Marginellidae family that ranges from Southern Alaska to Panama. The bright colouration shown in this photo comes from the animal’s “mantle” which is an extension of the “dorsal body”. The epidermis of the mantle can secrete CaCO3 to create a shell.

To see G. margaritula’s shell and mantle: http://calphotos.berkeley.edu/cgi/img_query?enlarge=0000+0000+03…
A special thank you to Dr. Alan Kohn at University of Washinton for his help in identifying G. margaritula.

This is the first one photographed underwater at Race Rocks

Compare the size Granulina margaritula to Flabellina verrucosa beside it in this photo.This “Three-lined” aeolid is seasonally abundant from Baja to Alaska (Behrens, 1991). Aeolids are opisthobranch gastropods known as sea slugs because they have lost their shells. This photo shows the nudibranch’s “oral tentacles” (bottom), ridged sensory antennae called “rhinophores”, “cerata” which contain stolen stinging cells for defense, and a “propodial tentacle”. This aeolid is common year-round at the Race Rocks Ecological Reserve where it is often observed feeding on hydroids such as Tubularia.
Macro images by Ryan Murphy

Other Members of the Phylum Echinodermata Mollusca at Race Rocks

Return to the Race Rocks Taxonomy and Image File

The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams. January 2011, Ryan Murphy