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worms > Phylum Platyhelminthes > Class Turbellaria > Order Polycladida
Sapphire flatworm
Pseudoceros caeruleocinctus
Family Pseudocerotidae
updated Feb 2020

Where seen? This beautiful worm is rarely seen.

Features: About 4cm long. Body black to reddish brown, margin bright blue, the outer margin comprising black with a very fine white outermost margin. Underside uniformly black with a fine white margin. The body is usually not highly ruffled. It has a pair of pseudotentacles that are simple and made up of folded edges of the body.

Tuas, Apr 05

Pseudotentacles made up of folded
edges of body margin.

Lazarus, Mar 20
Photo shared by VIncent Choo on facebook.

Sapphire flatworms on Singapore shores
On wildsingapore flickr

Grateful thanks to Rene Ong for sharing details and identifying the flatworms on this page.


  • Pseudoceros sapphirinus on Encyclopedia of Life, LifeDesks, Marine Flatworms - Polycladida: Technical fact sheet.
  • Rene S.L. Ong and Samantha J.W. Tong. 29 October 2018. A preliminary checklist and photographic catalogue of polyclad flatworms recorded from Singapore. Nature in Singapore 2018 11: 77–125
  • D. M. Bolaños, B. Q. Gan & R. S. L. Ong. 29 Jun 2016. First records of pseudocerotid flatworms (Platyhelminthes: Polycladida: Cotylea) from Singapore: A taxonomic report with remarks on colour variation.(pdf) The Raffles Bulletin of Zoology Supplement No. 34: 130-169  Pp. 130-169.
  • Newman, L.J. & Cannon, L.R.G. Pseudoceros (Platyhelminthes: Polycladida) from the Indo-Pacific with twelve new species from Australia and Papua New Guinea. The Raffles Bulletin of Zoology 1998 Pp. 293-323.
  • Newman, Leslie and Lester Cannon. 2003. Marine Flatworms: The World of Polyclads. CSIRO Publishing. 97pp.
  • Humann, Paul and Ned Deloach. 2010. Reef Creature Identification: Tropical Pacific New World Publications. 497pp.
  • Kuiter, Rudie H and Helmut Debelius. 2009. World Atlas of Marine Fauna. IKAN-Unterwasserachiv. 723pp.
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