DISTINCTIVE ASPECTS OF THE ZOOPLANKTON OF LARGE LAKES IN AUSTRALASIA,ANTARCTICA AND SOUTH-AMERICA

Not only has the degree of species-level cosmopolitanism amongst zoopl anktonic organisms been considerably overestimated, but differences be tween the different classical biogeographic regions (established from terrestrial studies) occur at supra-specific levels as high as family or even suborder. The Centropagidae, and particularly the genus Boecke lla, are found in New Zealand, most of Australia, southern and high al titude regions of South America, and around the periphery of Antarctic a. The biogeography and ecology of this family is discussed in detail. Most predaceous families of Cladocera are entirely absent from the Au stralian and Neotropical regions. The genus Daphniopsis occurs in salt lakes in Australia and South America and in freshwater lakes in Antar ctica. In southern Australia numerous species of ostracod have coloniz ed the limnetic region of salt lakes, and the largest of these prey on species of Calamoecia, Daphniopsis and small ostracods. Chaoboridae a re absent from New Zealand as, too, are obligate planktivorous fish. T he Chilean flamingo, Phoenicopterus chilensis, and Wilson's phalarope, Phalaropus tricolor, are significant predators on Boeckella poopoensi s in salt lakes on the Andean Altiplano and elsewhere in South America .