Ascidiacea (Tunicata) from deep waters of the continental shelf of Western Australia

Abstract

Seventy‐eight species of Ascidiacea, including 21 new species from deeper waters (about 100 m and occasionally to about 500 m) off Western Australia appear to represent a diverse fauna not previously sampled. The relatively few solitary species taken include two possibly introduced (Styela plicata and S. clava). Large aplousobranch colonies dominate the collections. Aplousobranch species with numerous, small, deeply embedded zooids in massive three‐dimensional, vertical and often branched or stalked inflexible colonies supported by embedded sand (Polyclinindae) or calcareous spicules (Didemnidae) are common. Species with flexible stalks (enabling them to respond to prevailing currents) such as Clavelina meridionalis, Sigillina australis and S. cyanea were not taken often. Some known species (e.g. Synoicum chrysanthemum, and Atriolum tubiporum) previously considered rare were taken at these depths in significant numbers. Other unusual taxa (Pseudodiazona longigona and Condominium spp.) are recorded from new locations but do not appear to be common.

Keywords:

• Protopolyclinidae
• Pseudodistomidae
• Polyclinidae
• Didemnidae

Acknowledgements

I am grateful to CSIRO Division of Marine and Atmospheric Research and Dr Alan Williams for the opportunity to examine material from the CSIRO survey SS10/2005 from the outer continental shelf off Western Australia.

The majority of the black and white drawings and scanning electron micrographs of spicules reproduced in this work were prepared by Michelle Baker, and the remainder by her predecessor Julie Anne Popple. Their salaries as my assistants were provided partly by a grant (2004–2007) to me from the Australian Biological Resources Survey (ABRS) and partly by CSIRO. Michelle's assistance in other ways contributed to the final compilation of this paper.

I am especially grateful to the Analytical Electron Microscopy Facility of the Queensland University of Technology, and in particular to Dr Thor Bostrom (Co‐Director) and Mr Loc Duong (Senior Technician) for their generous technical assistance to Ms Baker.

I also thank the Director and Trustees of the Queensland Museum for their continuing support in providing me with the accommodation and infrastructural support that enable me to pursue my work.