Contributions to the Biology of freshwater planarians (Turbellaria) from the Victorian Alps, Australia

The ten species of freshwater planarians known from Victoria, including one new species, are briefly reviewed. Detailed field and laboratory studies of six of these have been made and a close correlation between seasonal variation in numbers and viability at different laboratory temperatures is demonstrated. Thus Spathula camara and Reynoldsonia reynoldsoni inhabit temporary habitats that experience wide temperature fluctuations and these two species survive equally well in the laboratory at a wide range of temperatures. In contrast Spathula tryssa appears stenothermal in habitat and in the laboratory cannot tolerate even a small temperature increase. Cura pinguis and Dugesia (Girardia) sp. also show wide temperature tolerance both in terms of abundance in the field and viability studies in the laboratory. Spathula agelaea sp. nov. is unusual in that it shows two annual peaks in abundance and also exhibits aggregatory and cannibalistic behaviour that may be involved in population regulation. Aspects of the distribution, abundance, and life cycle, of all the species are discussed in relation to what is known generally of planarian ecology.