Flatworms; Platyhelminthes

Visitors to Koh Phangan, snorkelling or diving for the first time will often confuse Flatworms with Nudibranchs. Flatworms are more primitive animals and have no rhinophores or external gills (although, of course, it’s never quite that simple…)

Acanthozoon species

A commonly encountered flatworm, comfortable when swimming as well as moving over the bottom.

Genus Phrikoceros

These flatworms seem to have a distinctive ridge on the back and a special shape of head.

Genus Pseudobiceros

We're not sure of the determining characteristics of these beasties - they look wider than our Pseudoceros flatworms. (2 Galleries)

Genus Pseudoceros

They seem to be a little slimmer than their Pseudobiceros relations. (5 Galleries)

Planocerid Flatworm

Looks like a Nudibranch at first, with its rhinophore-like head tentacles.

Thysanozoon nigropapillosus

Up to 4 cm in length, with yellow spots on black, and white edges.

Other Flatworms; Platyhelminthes

Some tentatively named, others not, because they are not easy to classify even if they are listed...