Taxonomy and Biogeography of the Sea Star genus Patiriella in Tasmania

An annotated list of' the sea star fauna of Tasmania is given and an outline of the history of its investigation provided. The composition of the fauna is considered and although a small number of endemic forms are known its relationships are clearly with south-eastern continental Australia. This compares markedly with the New Zealand Asteroidea of which some 80 percent are endemic. Also whilst Tasmania and New Zealand possess some 15 genera of asteroids in common only six species are present in both areas. In Part II the taxonomy of the genus is Patiriella is considered in some detail. The form of the carinal abactinal plates is included as a diagnostic character for‚Äö the genus. The genus Patiriella is divided into regularis‚ÄövÑvp, exigua‚ÄövÑvp and gunnii‚ÄövÑvp groups and Patiriella gunnii (Gray) redescribed. A key to the species of Patiriella found in Tasmania is provided and geographic and vertical distribution considered. Some account of reproductive and feeding mechanisms, as far as they have been studied, is offered. An account of morphological variation as it affects choice of taxonomic characters is presented with particular reference to those characteristics offered by H.L.Clark (1946) and the distinction between Patiriella gunnii (Gray) and Patiriella brevispina H.L.Clark, about which there has been some confusion in the literature. The biogeography of the genus Patriella in the Southern Hemisphere is considered in Part III. Patiriella fimbriata (Perrier) is considered not to belong to the genus. It is suggested that the genus originated in the Indo-Pacific area and that the greatest proliferation of species has occurred along the east and south coasts of Australia. Hypothetical dispersal routes of forms of Patiriella have been constructed. The family Asterinidae is in great need of revision and familial and generic limits are still undefined in many cases. A prospectus is presented as an aid to future study of the Asterirddae and eventual revision of the family, it being considered that this thesis has laid a basis for further work. After the main text of this work was completed further information became available, mainly concerning the identity Patiriella exigua (Lamarek) and this is presented in the addenda. Five papers are bound at the rear of the volume as supporting evidence.