ascidians text index | photo index
Phylum Chordata | Subphylum Tunicata/Urochordata | Class Ascidiacea
Yellow clustered bead ascidians
Eudistoma sp.*
Family Polycitoridae
updated Mar 2020
Where seen? These clusters of yellow blobs are commonly seen on many of our Northern shores, on hard surfaces near the mid-water mark.

Features: Each blob about 1cm across, somewhat columnar with a rounded top. Clusters of blobs form on boulders and larger rocks, usually near the base and under overhangs. Also on jetty pilings.

Blue-dot margined flatworms have been seen near them, appearing to envelope a similarly shaped object. Do these worms eat the ascidian?
Labrador, Mar 05

Are they eaten by the Blue-dot margined flatworm?
Changi, Jun 08

Tuas, Nov 03

Chek Jawa, Sep 02

Changi, Jun 08

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

Yellow clustered bead ascidians on Singapore shores
On wildsingapore flickr

Other sightings on Singapore shores

Berlayar Creek, Dec 10
Photo shared by Loh Kok Sheng on flickr.

Cyrene, Jun 20
Photo shared by Kelvin Yong on facebook.

Beting Bemban Besar, Mar 20
Photo shared by Kelvin Yong on facebook.

Terumbu Pempang Tengah, Nov 18
Photo shared by Richard Kuah on facebook.

Terumbu Pempang Laut, Dec 18
Photo shared by Liz Lim on facebook.

  • Chim C. K., R. S. L. Ong & Gan B. Q. Penis fencing, spawning, parental care and embryonic development in the cotylean flatworm Pseudoceros indicus (Platyhelminthes: Polycladida: Pseudocerotidae) from Singapore. 10 July 2015. The Comprehensive Marine Biodiversity Survey: Johor Straits International Workshop (2012) The Raffles Bulletin of Zoology 2015 Supplement No. 31, Pp. 60-67.
  • Allen, Gerald R and Roger Steene. 2002. Indo-Pacific Coral Reef Field Guide. Tropical Reef Research. 378pp.
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