Ascidia glabra   Hartmeyer,  1922 (Sea Squirt)
Organism information awaits expert curation
Class: Ascidiacea

Image copyrights: The Marine Biological Association of India

Size: 4 cm long and 2 cm broad with the posterior end rounded and anterior end narrow.

Color: Live individuals are pale straw colored.

Laterally compressed and attachment is by the whole of the left side. Apertures are on short conical ridged siphons. The branchial aperture is terminal and the atrial aperture half the distance from the anterior end on the dorsal surface. There are 7 branchial and 8 atrial lobes on the apertures with ocelli between the lobes. The lobes do not have tentacular fringe. Test thin, soft and translucent with faint longitudinal striations. There are minute papillae on the surface concentrated near the apertures. Minute test hairs are present. Test vessels branch profusely, there are no papillae and in the main test vessel the red blood cells were found.

The body wall is thin, delicate with a meshwork of muscles on the right side. On the left only longitudinal muscles are present anterior to the gut loop. More than 120 branchial tentacles crowded at the base of the branchial siphon. Prebranchial area narrow. Peritubular area very shallow. The dorsal tubercle is a large cushion with a V-shaped slit with both the horns turned in. The neural ganglion is midway between the dorsal tubercle and the atrial aperture. The dorsal lamina is ribbed membrane double anteriorly. Branchial sac with shallow pleat. Internal longitudinal vessels with triangular papillae. The meshes are rectangular with 5-6 stigmata. There is no intermediate branchial papilla. The gut loop is deeply curved. The oesophagus is short, stomach smooth, pear shaped. Primary gut loop long. Rectum proceeds anteriorly and opens at the base of the atrial siphon. Anus has a smooth border and is more or less in level with the pole of the gut loop. Gonads in the gut loop. The proximal end of the ovary branched. The branches are short and bunched. They do not project beyond the border of the gut loop. Testis follicles small and spread all over the mesial surface of the gut loop.

Similar species: It resembles Ascidia gemmata in its habit, nature of test, number of lobes in the siphons, branchial tentacles, the mesh of muscles on the right side, the position of neural ganglion presence of ridged siphons, etc. But it is distinguished from Ascidia gemmata by its shorter and more numerous stigmata and the position of the anus more or less in level with the anterior pole of the gut loop.

Synonym (s)

Common Name (s)
Economic Importance and Threats

Habitat:  Demersal, Rocky, Coastal


• Tamil Nadu, Valinokkam Port INDIA

Literature Source(s)
  • Meenakshi, VK (2005) Addition to the ascidian fauna of India Journal of the Marine Biological Association of India Marine Biological Association of India, Cochin 47(1) 36-49 Available at - NIO, Goa
  • Society for the Management of European Biodiversity Data (2009) World Register of Marine Species (WoRMS) Available at -
  • Sealifebase Available at -

Page last updated on:2010-08-18

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