Asteronotus sponicolus Gosliner & Valdes, 2002
Talk about a plain Jane. Most of us who have dived the south Pacific have looked right at this guy and never seen it. Cryptic as all heck. Ruben shared that when he took this shot it "appeared as a bump on the coral, and was totally attached, with very little demarcation. It didn't even react to touch." I believe that the substrate the slug is sitting on is actually a sponge.
Aside from the substrate this species is common found on; its key identifying feature is the light stripe down the middle of the dorsum ending between the rhinophores.
Both A. sponicolus and its sister species, Asteronotus mimeticus can be found feeding on the underside of the sponge Carteriospongia sp. in shallow water on patch reefs. The bland coloration makes the slug almost impossible to see, so turn the sponge over carefully and look closely.
Both of the species are presented in Indo-Pacific Nudibranchs and Sea Slugs. If you don't have a copy, sorry - the book sold out this month!
This species is known from Tanzania, eastern Australia, Malaysia and the Philippines.
Dr. Ruben Sarkissian on location somewhere
in the Banda Sea
Ruben is a retired Dentist and Faculty. Diving since 1980 with over 5000 dives. Shoots Nikon D200 in SeaCam Housing with Sea and Sea Strobes.
Send Ruben email at firstname.lastname@example.org