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Species
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Species

Species - Botryllus schlosseri

Scientific name:
Botryllus schlosseri (Pallas 1766)
Common name:
star ascidian
Developments:
Report to NIMPIS of specimen with characteristics consistent with B. schlosseri from Bunbury, WA. Specimen was washed up after a storm in June 2020 (see photo).
General description:
Summary Description

Botryllus schlosseri is an colonial ascidian composed of many individual asexually produced zooids arranged in clusters. Colonies vary in size and shape from sheets to stalked or sessile, fleshy lobes. Colour is variable from purple or brown to colourless tests with yellow, white or orange zooids. The 3 mm long zooids are arranged in circular or elongate flower-like clusters, with all zooids in a cluster sharing a large, circular opening - an exhalant siphon. Spherical ampullae (small bumps) occur in the test between the zooids and become more elongate at the edges of the colony. Internally, the inhalant siphon (atrial aperture) is small, the body wall forming a broad siphon, with a small lip on the upper border of the opening.
Australian distribution:
Established
Detected in:
Tasmania
Victoria
Western Australia
Invasion status:

Cryptogenic

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Caption:
Botryllus schlosseri.

Source:
Copyright Notice: Karen Gowlett-Holmes, CSIRO Marine Research. Acknowledge: true
Caption:
Botryllus schlosseri.

Source:
Copyright Notice: Karen Gowlett-Holmes, CSIRO Marine Research. Acknowledge: true
Caption:
Botryllus schlosseri diagram & key features. Colonial ascidian. Firm and fleshy test. Colonies grow as sheets. Zooids in groups sharing exhalant siphons. Location of the developing ova (protrudes into the atrial cavity - not shown on diagram).

Source:
Copyright Notice: Diagram: Kott, 1985. Acknowledge: true
Caption:
Acsidian with characteristics consistent with Botryllus schlosseri found on beach at Bunbury, WA.

Source:
Korben Paddick, 6 June 2020 Report submitted to NIMPIS

Last modified: 6 July 2020