Nudibranchs and Sea Slugs of Guam (Part IV)

The first nudibranch appears to be Phidiana salaamica, though the species is known only from Tanzania and Japan; it is possible that they were accidentally transported to Guam on the hulls or in the ballasts of ships.  Pleurobranchs, such as this Pleurobranchus albiguttatus, are also known as "side-gilled slugs" and are mostly nocturnal carnivores.  These Phyllaplysia sp. are members of the "sea hare" family, and are masterfully camouflaged to the only species of grass on which they live; in the daytime they are buried deep at the base of the grass, and only come out at night.  This unidentified dorid looks like a member of the Dendrodoris genus; while most nudibranchs have tooth plates know as "radulae", dendrodorids secrete digestive enzymes on sponges and ingesting the digested tissues.  One of the more charismatic nudibranchs, Risbecia tryoni is know to exhibit regular "mantle-flapping", as seen in this video; the purpose of this behavior is unknown, though it may aid in sensing chemical cues in the water.  This unidentified discodorid is well-camouflaged as a sponge, the main source of food for this group of nudibranchs.  Another pleurobranch, this Berthellina sp., has recently ingested a small snail, which can be seen through the body of the slug.  The fantastical coloring and shape of Halgerda tesselata actually makes them hard to find; however, once an observer discovers them, they become one of the most commonly seen nudibranchs on Guam.  In this video you can see two H. tesselata mating through the genital openings on the right sides of their bodies.