Tentacles and naked gills

February 24, 2014

Despite the recent series of unfortunate oil spills that occurred in our southern waters, it was a glorious weekend for divers over at Pulau Hantu yesterday! Lots of nudibranches and other spineless creatures tried to be cryptic but could not escape the eyes of our experienced and nosy guides! Above is a series of photographs that depict the swimming behavior of the Starry bornella (Bornella stellifer) © Jeemee Goh/Hantu Blog

Jorunna funebris

Phestilla melanobrachia is a relatively large aeolid nudibranch (to 40mm long) that has been recorded from southern Japan, and Hawaii, to northeastern Australia, suggesting a western Pacific distribution. It has both bright orange-yellow and black colour forms. Its colour matching the colour of the coral (Tubastrea, Dendrophyllia) on which it is feeding. The “frilly” part of its body, the cerata, have been likened more to ‘arms’ – brachia, rather than ‘gills’ – branchia. Hence the name! [Source]

Cadlinella ornatissima

From left: Glossodoris pallida is characterised by the opaque white marks on the mantle; Ceratosoma gracillimum amongst a bed of hydroids.

Many species of Phyllodesmium have evolved a symbiotic relationship with single-celled plants called zooxanthellae which they keep alive in their bodies, and living to some extent from the products of the zooxanthellae photosynthesis. Phyllodesmium serratum (above) does not have such a relationship, and is unusual in feeding on a wide variety of octocorals. As colour is dependent on the colour of the food they are eating, this species is highly variable in colour except for the white median dorsal line. [Source]