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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

References & Links

Abbott, DP & Newberry A 1980, Intertidal invertebrates of California: Urochordata- the tunicates,pp.177-226, Stanford University Press, USA.

Akhmadieva, AV, Shukalyuk AI, Aleksandrova, YN & Isaeva VV 2007,‘Stem cells in asexual reproduction of the colonial ascidian Botryllustuberatus (Tunicata: Ascidiacea)’, RussianJournal of Marine Biology, vol.33 (3), pp.181-186.

Australian Museum 2009, Image of heron island, viewed on 4thJune 2014, <>

Boyle, M, Janiak, D & Craig, S 2004, Succession in a HumboldtBay marine fouling community: The role of exotic species, larval settlement andwinter storms, Proceedings of the 2004Humboldt Bay symposium

Cima, F, Ballarin, L, Gasparini, F & Burighel, P 2006, ‘Externalamebocytes guard the pharynx entry in a tunicate (Ascidiacea)’, Develpmental and Comparative Immunology,Vol. 30, pp. 463-472. 

Cima, F, Bragadin, M & Ballarin, L 2008, ‘Toxic effects of newantifouling compounds on tunicate haemocytes I. Sea-Nine 211TM and chlorothalonil’, Aquatic toxicology, vol. 86, pp. 299-312. 

Delsuc, F, Brinkmann, H, Chourrout, D & Philippe, H 2006, ‘Tunicatesand not cephalochordates are the closest living relatives of vertebrates’, Nature, vol.439, pp. 965-968. 

Flood, PR & Fiala-Medioni, A 1981, ‘Ultrastructure andhistochemistry of the food trapping mucous film in benthic filter-feeders(Ascidians)’, Acta Zoologica, vol.62,pp. 53-65. 

Fiala-Medioni, A, 1978, ‘A scanning electron microscope study of thebranchial sac of benthis filter-feeding invertebrates (Ascidians)’, Acta Zoologica, vol.59, pp.1-9.

Gittenberger, A 2011, Dutch Ascidian Website, viewed 4thJune 2014, <>

Kott, P 1985, ‘The Australian Ascidiacea Part I, Philebobranchia andStolidobranchia’, Memoirs of theQueensland Museum, vol. 23, pp. 1-440. 

Kott, P 1989, ‘Form and function in the ascidiacea’, Bulletin of Marine Science, vol.45 (2),pp. 253-276. 

Kott, P 2005, Ascidiacea of Catalogue of Tunicata in AustralianWaters (CTAW), viewed 4th June 2014, <>

Lesser, MP, Shumway, SE, Cuccia, T & Smith, J 1992, ‘Impact offouling organisms on mussel rope culture: interspecific competition for foodamong suspension-feeding invertebrates’, Journalof Experimental Marine Biology and Ecology, vol. 165, pp. 91-102. 

Lukowiak, M 2012, ‘First record of late Eocene ascidians (Ascidiacea,Tunicata) from southeastern Australia’, Journalof Paleontology, vol.86 (3), pp. 521-526.

MacGinite, GE 1939, ‘The method of feeding of Tunicates’, Biological Bulletin, vol.77 (3),pp.443-447.

McHenry, MJ 2005, ‘The morphology, behaviour and biomechanics ofswimming in ascidian larvae’, CanadianJournal of Zoology, vol. 83, pp. 62-74. 

Pennati, R, Groppelli, S, Bernardi, FD, Mastrototaro, F & Zega,G 2009, ‘Immunohistochemical analysis of adhesive papillae of Clavelina lepadiformis (Muller, 1776)and Clavelina phlegraea (Salfi, 1929)(Tunicata, Ascidiacea)’, European Journalof Histochemistry, vol. 53 (1), pp. 25-34. 

Petersen, JK 2007, ‘Ascidian suspension feeding’, Journal of Experimental Marine Biology andEcology, vol.342, pp.127-137. 

Rocha RM & Kremer LP 2005, ‘Introduced ascidians in ParanaguaBay, Parana, southern Brazil’, RevistaBrasileira de Zoologia, vol.22(4), pp.1170-1184.

Ruppert, EE, Fox, RS & Barnes, RD 2004, Invertebrate zoology: A functional evolutionary approach, 7thedn, Brooks/Cole, Belmont USA. 
Shenkar N & Swalla, BJ 2011, ‘Global diversity of Ascidiacea’, PLoS ONE,vol.6 (6), pp.1-12. 

Simkanin, C, Davidson, IC, Dower, JF, Jamieon, G & Therriault,TW 2012, ‘Anthropogenic structures and the infiltration of natural benthos byinvasive ascidians’, Marine Ecology,vol.33, pp.499-511.

Vlaams Instituut voor de Zee 2014, WoRMS- Ascidiacea WorldDatabase, viewed 4th June 2014,<>