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worms > Phylum Platyhelminthes > Class Turbellaria > Order Polycladida
Blue-dot margined flatworm
Pseudoceros indicus*
updated Oct 2016

Where seen? This little flatworm with blue dots on its body margin is often seen on many of our shores. On rocky shores, on boulders and under stones, also near reefs.

Features: 2-3cm long. Body uniformly white or cream with closely-set dark blue dots along the body margin. When the worm is contracted, the dots merge so the worm appears to have a solid blue margin. Sometimes with a faint central stripe, white or pale brown. The body margins are only slightly ruffled when the worm is in water. It has a pair of erect pseudotentacles at the front made up of folded edges of the body.

The worms have been observed enveloping spherical objects. Could they be eating the Yellow clustered bead ascidians (Eudistoma sp.) that grow on the rocks? They have also been seen on Beige sheet ascidians.

Pulau Sekudu, Jul 05

Front end of the worm.

Seen on Beige ascidians.
Chek Jawa, Aug 05

Pulau Hantu, Mar 06

Eating Yellow clustered bead ascidians?
Changi, Jun 08

*Tentative identification. Species are difficult to positively identify without close examination.
On this website, they are grouped by external features for convenience of display.

Blue-dot margined flatworms on Singapore shores

Photos of Blue-dot margined flatworms for free download from wildsingapore flickr

Distribution in Singapore on this wildsingapore flickr map

Beting Bronok, Jun 10
Photo shared by Loh Kok Sheng on his flickr.

Sentosa Serapong, May 16
Photo shared by Ian Siah on facebook.

Seringat-Kias, Nov 14
Photo shared by Marcus Ng on facebook.

Pulau Tekukor, May 10
Photo shared by Loh Kok Sheng on his blog.

Sisters Island, Aug 09
Photo shared by Neo Mei Lin on her blog.

Pulau Semakau, Aug 14
Photo shared by Russel Low on facebook.

Beting Bemban Besar, Apr 10
Photo shared by Loh Kok Sheng on his flickr .

Terumbu Bemban, Jun 10
Photo shared by Toh Chay Hoon on her blog.

Terumbu Selegie, Jan 17
Photo shared by Loh Kok Sheng on his blog.

Terumbu Raya, May 10
Photo shared by Toh Chay Hoon on her blog.

Terumbu Semakau, Dec 11
Photo shared by James Koh on his blog.

With grateful thanks to Leslie H. Harris of the Natural History Museum of Los Angeles County for comments on this worm and its identification.


  • Pseudoceros indicus on Encyclopedia of Life, LifeDesks, Marine Flatworms - Polycladida: Technical fact sheet.
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