Ciliated protozoa from a volcanic crater-lake in Victoria, Australia

Abstract

We have investigated the ciliated protozoa living in the crater-lake of an extinct volcano in Australia. Our principal objective was to discover if such a habitat— geographically distant and isolated from Europe (the latter having provided most of the diversity on which ciliate taxonomy is based)— could yield species that were unusual, and perhaps new to science. Numerous samples were taken from the superficial layer of lake sediment, and examined fresh in the laboratory. Thereafter, the samples were manipulated to encourage growth of rare and cryptic ciliate species. Eighty-five species of ciliated protozoa were identified. None of these was new, all having been found previously in fresh-or brackish water, sea water, or soil. All, apart from one (Oxytricha salmastra), are already known from Europe. In order to test our ability to discover new ciliate species, we examined a variety of water samples from other lakes, including those known to harbour endemic algae. One new ciliate species (Lembadion curvatum) was discovered in a lake in Western Tasmania. We conclude that the ciliate fauna of Australia is remarkably similar to that in Europe and other parts of the world. This is supported by the example of those ‘endemic’ ciliate species described in the literature which have, in response to additional sampling, been found elsewhere in the world.

Keywords:

• Cosmopolitan
• Australia
• Biogeography
• Dispersal
• Southern
• Hemisphere
• Soil Ciliates
• Freshwater
• Marine
• Lembadion