Glossodoris hikuerensis (Pruvot-fol, 1954)
This week we feature a remarkable photo of an equally remarkable species. This is Glossodoris hikuerensis, a chromodorid nudibranch known from throughout the tropical Indo-Pacific, and the Red Sea. In Constantionos' photo here we see one of several defense mechanisms utilized by opisthobranch to ward off predators. As mentioned in previous BOW's, some members of the Chromodorididae have acid glands buried in the tissue along the margin of the mantle. When antagonized, tiny pores connecting these glands to the surface of the notum open and release their acid substance in a cloud or stings as seen here. Although the actual chemical mechanism is unknown, the response by predators is pretty acute, as they leave the nudibranch alone immediately.
This interesting behavioral activity is just one of many featured in Constantinos' new book - Realm of the Pigmy Seahorse
Originally described from the Tuamoto Archipeligo of the Society Islands, Glossodoris hikuerensis is similar in coloration to Glossodoris cincta as seen in Mary Jane Adam's photo on Bill Rudman's Sea Slug Form. In Glossodoris hikuerensis the three marginal bands are wider and of different color, the outer band being pale brown, followed by a whitish band and an inner blackish band.
An interesting features of the anatomy in this genus is the large spiraling
gills. From the side view they almost look like several Christmas tree
worms on the back of the dorid. On the Sea Slug Forum , Bill
Rudman suggests that as the individual grows larger the increase in the
number of gills provides increased surface area for respiratory gas
exchange. This is a plus, as larger animals have thicker skins which
reduce gas exchange over the body surface.
Realm of the Pygmy Seahorse 2001.
Award-winning photographer Constantinos Petrinos, chose the Lembeh Strait in North Sulawesi, Indonesia to document this fascinating underwater wonderland. He spent 5 months in the region, did 320 dives and took 25,000 slides. This book features 280 of these amazing photographs. Underwater photographers will find a wealth of information on technique. For the naturalist, the rich text explains the spectacular behavior seen in the photographs.
David W. Behrens
Pacific Coast Nudibranchs