Observations on non‐didemnid ascidians from Australian waters (1)

Abstract

Thirty‐five species (including eight that are new) of non‐didemnid aplousobranch species and 25 phlebobranch (including one new) and stolidobranch species are discussed and a further 42 species in non‐didemnid taxa in all suborders are newly recorded. Material was taken by scuba diving in the waters around Kangaroo I. and other southern Australian and Tasmanian locations; and further material was taken by dredge from canyons off the southeastern Continental Slope and from inter‐reefal areas in the northern Great Barrier Reef region. The known geographic ranges of many southern Australian species are extended into Tasmanian waters and a new species of Rhopalaea is described from the Tasmanian Canyons. The genera Sigillina and Pseudodistoma are found to be diverse in Australian temperate waters, and they have many characters in common, suggesting a probable phylogenetic relationship that formerly was not recognised. The greatest diversity of species reported is from the vicinity of the northern Great Barrier Reef. Almost without exception these are non‐indigenous tropical species often extending into Australian temperate locations where they are sympatric with indigenous species found mainly around the southern half of the continent. Pyura stolonifera has a similar range in temperate Australian waters but appears also to occur on the South African and Chilean coasts in similar habitats and may represent a Gondwana relict.

Keywords:

• Aplousobranch
• Great Barrier Reef
• indigenous
• new species
• non‐indigenous
• phlebobranch
• Pseudodistoma
• Pyura stolonifera
• Rhopalaea
• Sigillina
• stolidobranch
• Tasmania
• temperate
• tropical

Acknowledgements

Again, Karen Gowlett Holmes' beautifully photographed material, on this occasion from Kangaroo I. and Port Davey (south‐western Tasmania), has appreciably added to our understanding of the indigenous species of Australian temperate waters. Also, I am grateful to CSIRO and Dr Alan Williams for the opportunity to examine material from the deep water canyons of the continental slope off northeastern and northwestern Tasmania. The tropical material examined in connection with this paper is part of a collection made in a joint programme conducted by the Queensland Museum, the Australian Institute of Marine Science, and CSIRO Marine Research. In this programme, known as the GBR Biodiversity Project, the inter‐reefal sea‐floor habitats of the northern Great Barrier Reef are being systematically surveyed. The material was sorted into phyla in the Museum of Tropical Queensland (Townsville) under the direction of Dr Peter Arnold and I am grateful to have had this opportunity to examine the tunicates collected. The black and white drawings were prepared by Eileen Salisbury, whose salary as my assistant is provided by a grant (2004–2007) to me from the Australian Biological Resources Survey (ABRS). Her assistance in many other ways contributed to the compilation of this paper. I also thank the Director and Trustees of the Queensland Museum for their continuing support by providing me with the accommodation that enables me to pursue my work.