New syntheses and new species in the Australian Ascidiacea

Fifty-one species are discussed of which five are new. Of the remaining 46 species, 20 previously known from one to three records and 11 more frequently recorded have their known geographic range and/or range of morphological variation extended and the synonymy of a further 15 species is revised. Taxonomic problems, including phylogeny, are addressed in Rhopalaea crassa, Pycnoclavella detorta, Ecteinascidia spp. and Plurella (see Phallusia polytrema). New species are Sigillina pulvinus, Polyclinum corbis, Perophora longicaulis, Stolonica brevigastra and Botrylloides saccus.