Eudistoma laysani   (Sluiter,  1900) (Sea Squirt)
Organism information awaits expert curation
Class: Ascidiacea

Image copyrights: Teresa Zubi

Colour: Living colonies are bluish white irridescence and colourless in preservative.

Colonies are lobed with a basal mass of common test. The lobes have a cylindrical stalk which expands into a flat or rounded head covered by delicate transparent test. Crowded faecal pellets make the stalks opaque. The stalk is covered by epibionts but devoid of sand. zooids open separately and there are no systems, 40-50 zooids are present in a lobe. Well expanded zooids are narrow, very long, with a long oesophageal neck; thorax about 1mm; circular muscles are present only in the thora. The atrial siphon originates opposite to the first row of stigmata. The smooth stomach at the posterior end of the abdomen and an oval posterior stomach. Gonads present in the gut loop; 2-3 embryos in the atrial cavity. An otolith and an ocellus are present.

Synonym (s)
Archidistoma parva (Sluiter, 1900)
(New combination)
Distoma laysani Sluiter, 1900
(Original combination)
Distoma parva Sluiter, 1900
(Original combination)
Eudistoma parva (Sluiter, 1900)
(New combination)
Polycitor laysani (Sluiter, 1900)
(New combination)

Common Name (s)
Economic Importance and Threats

Habitat:  Demersal, Rocky, Coastal


• Tamil Nadu, Mandapam (Lat: 9.28) (Long: 79.12) INDIA
• Kerala, Vizhinjam Bay INDIA
• Kerala, Vizhinjam Bay (Lat: 8.37) (Long: 76.93) INDIA
• Tamil Nadu, Kadiapattanam (Lat: 8.12) (Long: 77.30) INDIA (Record: 2002-2003)
• Tamil Nadu, Valinokkam INDIA
• Tamil Nadu, Mandapam INDIA
• Tamil Nadu, Ervadi INDIA

Literature Source(s)
  • Rao, DVS (2005) Comprehensive review of the records of the biota of the Indian Seas and the introduction of non-indigenous species Aquatic Conservation: Marine and Freshwater Ecosystems John Wiley and Sons, Ltd. 15(2) 117-146 Available at -
  • van der Land, J UNESCO-IOC Register of Marine Organisms Available at -
  • Society for the Management of European Biodiversity Data (2009) World Register of Marine Species (WoRMS) Available at -
  • Abdul, JAH and Sivakumar, V (2007) Occurrence and distribution of ascidians in Vizhinjam Bay (south west coast of India) Journal of Experimental Marine Biology and Ecology 342(1) 189-190 Available at -
  • Sealifebase Available at -
  • Starfish Available at -
  • Jaffarali, HA; Sivakumar, V and Selvi, MT (2010) New records of colonial Ascidians from the South West coast of India Middle-East Journal of Scientific Research IDOSI Publications 5(5) 366-373 Available at -
  • Jaffar Ali, AH; Sivakumar, V and Tamilselvi, M (2009) Distribution of Alien and Cryptogenic Ascidians along the Southern Coasts of Indian Peninsula World Journal of Fish and Marine Sciences IDOSI Publications 1(4) 305-312 Available at -
  • Meenakshi, VK. (2002) Occurrence of a new species of colonial ascidian- Eudistoma kaverium sp.nov. and four new records of Eudistoma to Indian coastal waters Indian Journal of Marine Sciences Scientific Publishers 31(3) 201-206 Available at -

Page last updated on:2011-02-07

Back to Search