Phallusia arabica   Savigny,  1816 (Sea Squirt)
Organism information awaits expert curation
Class: Ascidiacea

Image copyrights: The Marine Biological Association of India

Size: Length 2.5-6.5 cm

Color: Smoke grey to dark brown. Young individuals are translucent white.

The individuals are fixed upright to the substratum by the posterior end of the body or by the posterior left side. They are oval to elongate with a slightly laterally compressed body. The surface test is naked, free of epibionts with longitudinal ridges extending from the siphons to the middle of the body. Generally, the test is thicker around the dorsal side than the other regions, but thinner where it is attached to the substrate. The test is firm, rigid, smooth and translucent. The branchial aperture is terminal. The branchial siphon is long, cylindrical and thick. The atrial siphon is short, cylindrical and lies halfway along the dorsal surface. Both the siphons are ridged. The atrial siphon is usually directed anteriorly or to the sides whereas the branchial siphon is rarely directed laterally and never posteriorly. There are 6-9 branchial lobes and 5-9 atrial lobes with ocelli between them. The main test vessel enters the test halfway from the anterior end to the left side of the ventral line. The vessels branch and small terminal vessels are evenly distributed on the test. The surface test has mass of pigments giving a prominent marking.

Both the siphons have well developed circular and longitudinal muscles. The right side of the body has strong longitudinal and transverse muscles bands forming a meshwork; musculature on the left side is feeble. Mantle is light brown to translucent. There are about 50-70 branchial tentacles of two sizes, long and short. The narrow prebranchial area is papillated. No V-shaped peritubercular area. The branchial sac is deeply plicated. There are about 10-12 stigmata in a mesh. Large tongue shaped branchial papillae are present at the junction of the internal longitudinal vessels with the transverse vessels. The gut loop is confined to the posterior half of the body. A short oesophagus arises from the middle of the dorsal lamina. The stomach has faint longitudinal striations. Opening of the anus is mostly smooth and rarely with small lobes.

The ovary is highly branched and situated in the primary gut loop. Testis follicles are present surrounding the ovary and also on the surface of the gut.

Synonym (s)
Phallusia philippinensis Millar, 1975
(Junior synonym)
Phallusia depressiuscula Tokioka, 1970
(Junior synonym)

Common Name (s)
Economic Importance and Threats
Importance:  Dangers
(Important component of the biofouling community)

Habitat:  Demersal, Rocky, Coastal


• Tamil Nadu, Tuticorin INDIA
• Tamil Nadu, Tuticorin (Lat: 8.75) (Long: 78.20) INDIA (Record: 2002-2003)
• Tamil Nadu, Tuticorin Harbour INDIA

Literature Source(s)
  • Meenakshi, VK and Senthamarai, S (2004) First report of a simple ascidian - Phallusia arabica Savigny, from Tuticorin coast of India Journal of the Marine Biological Association of India The Marine Biological Association of India, Cochin 46(1) 104-107 Available at - NIO, Goa
  • Society for the Management of European Biodiversity Data (2009) World Register of Marine Species (WoRMS) Available at -
  • Sealifebase 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; Renganathan, TK; Senthamarai, S and Jeyalakshmi, J (2003) Marine biodiversity - Taxonomy of Indian Ascidians Technical report Available at - Biodiversity Informatics Group, NIO, Goa

Page last updated on:2011-02-22

Back to Search