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Botryllus tuberatus (Ritter & Forsyth, 1917)

Pacific Star Tunicate

Adeline Ang (2014)



Fact Sheet

Brief Summary

Physical Description

External Features

Internal Features

Slides Preparation


Life History & Behaviour

Feeding Mechanisms


Internal Transport & Movement

Asexual Reproduction

Sexual Reproduction

Anatomy & Physiology

Evolution & Systematics

Biogeographic Distribution

Biofouling Threats

References & Links


B. tuberatus, just like any other ascidian, uses the branchial basket as a mode for respiration as well.  As mentioned under the section 'Feeeding mechanisms', fresh seawater flows from the incurrent aperture of the individual zooids, through the branchial basket whereby gaseous exchange occurs, and out of the excurrent aperture into the common cloacal aperture, and then expelled (Kott 1989).  The arrangement of the zooids is such that the incurrent apertures of the individual B. tuberatus zooids are facing away from the common cloacal aperture, so as to minimize the amount of water re-entering the organism before it could be carried away by the currents (Kott 1985).