Pseudobiceros sp. 1

kingdom: Animalia
phylum: Platyhelminthes
class: Rhabditophora
order: Polycladida
family: Pseudocerotidae
genus: Pseudobiceros
species: Pseudobiceros sp. 1

Pseudobiceros sp. 1 is a marine polyclad flatworm in the family Pseudocerotidae. It has not yet been formally described, so it has no species name.

This one has a green-yellow body. Like other Pseudobiceros, it has a pair of small folded flaps at the front, called pseudotentacles, which work like a nudibranch's rhinophores to sense the water.

Flatworms are often mistaken for nudibranchs, but they are paper thin and have no gills on the back. They glide over the reef on a rippling body edge and can even swim by flapping it. Many polyclads in this family feed on sea squirts and other small invertebrates.

In the Philippines flatworms turn up on reefs and rubble slopes on both day and night dives. They move faster than most sea slugs, so set your focus early and shoot as the front edge lifts to show the pseudotentacles.