Modern and fossil ostracods from ancient lakes.

Ancient lake systems contain incredibly rich archives of past biological and environmental change. Ostracods have long been associated with ancient lakes, largely because as a group they are common in such habitats, often occupy specific ecological niches and, generally, can be relatively easily studied. In addition, their excellent potential for preservation ensures that they frequently have a long fossil record, thereby providing a convenient means for investigating temporal changes in the lake system. Here we use a combination of biological and geological criteria to classify ancient lakes and, by means of a series of case studies using both extant and fossil exam-ples, go on to review some of the evolutionary and palaeoclimatic issues that can be addressed with respect to ancient lake ostracod faunas. We also high-light some of the current deficiencies in the field and make a call for more concerted research, not only from taxonomic and ecological standpoints, but also in the provision of rigorous chronological control for fossil sequences. The potential to couple both modern and fossil faunal data with new genetic analysis techniques will ensure that ostracod studies remain at the forefront of palaeoclimatic and evolutionary research in ancient lake environments.