Ascidia tuticoriensis     (Sea Squirt)
Organism information awaits expert curation
Class: Ascidiacea

Image copyrights: The Marine Biological Association of India

Size: 7.5 cm long and 2.5 cm wide

The individual is roughly oval or egg shaped with a rounded posterior end. The body is laterally flattened with the right side having a prominent ridge from the outer side of the base of the branchial siphon to the postero-dorsal side. This makes the right side to have a triangular surface with the ridge forming its apex. The branchial aperture is terminal and the atrial aperture one-third from the anterior end on the dorsal surface. The siphons are moderately long, branchial siphon 2 cm and atrial siphon l.5 cm long. Both the siphons are ridged, directed anterio-dorsally and the ridges are crossed by circular furrows so that on the siphons small squarish markings are present. Test cartilaginous and opaque. Epibionts and sand present on the outer surface along with fairly large papilla like outgrowths more on the anterior side. The branchial aperture has 8 lobes and the atrial aperture 6 lobes. Each lobe has 7 tentacular fringes. Attachment only by the posterior left side so that the individuals look upright in posture.

The internal siphons are also as long as the external siphons with well developed circular muscles. The longitudinal muscles radiate from the siphons extend onto the right side and together with the transverse muscles form an irregular mesh which straightens to form transverse bands along the ventral margin. On the left side musculature is present only anterior to the gut loop. There are more than 80 branchial tentacles of 3 different sizes arranged on a velum. Prebranchial area is moderate. Peritubercular area V-shaped. Dorsal tubercle large and has a V-shaped slit with one horn turned out. Dorsal ganglion lies just posterior to the dorsal tubercle. Dorsal lamina is a ribbed membrane double anteriorly. Branchial sac pleated with 6-8 stigmata in a mesh. Branchial papillae are rounded with a projection at their concave base. Small conical intermediate branchial papillae are present at the crossings of parastigmatic vessels. The gut forms a deeply curved loop. Oesophagus short, stomach elongate with faint striations. The axis of the gut loop passes through the pyloric end of the stomach. The intestine is not distended with mud. Anterior margin of the gut loop is in level with the atrial siphon. The anus has a smooth border and lies posterior to the pole of the gut loop. Gonads in the gut loop. The ovary has short branches which occupies the primary and secondary gut loop. Testis follicles are spread over the gut loop.

Similar species: The present species resembles Ascidia occidentalis Kott, 1985 in the presence of tentacular fringe on the lobes of apertures and a mesh of muscles on the right side of the body. But it differs from the latter in the external appearance, attachment to the substratum, presence of fewer stigmata in a mesh, the internal longitudinal vessels with conical intermediate branchial papillae and the anal opening posterior to the pole of the gut loop. These differences are considered to be of taxonomic significance and hence treated as a new species.

Synonym (s)

Common Name (s)
Economic Importance and Threats



• Tamil Nadu, Off Tuticorin INDIA (Record: 2005) (Depth: -5 mts)

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 -

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