Speciation in ancient lakes: ecology and evolutionary diversification of spiny-eels from Lake Tanganyika

Research context The East African great lakes, some of the richest freshwater ecosystems on Earth, are regarded as biodiversity hotspots. Fascination with these ecosystems is in part because the lakes are home to hundreds of endemic species. As such they provide natural experimental settings in which to study processes that underlie speciation. Lake Tanganyika (LT), differs from other lakes, in harbouring multiple radiations of different animal groups, making it a particularly appealing comparative system to examine adaptive radiation and within lake diversification. Research efforts have focused on the much-celebrated cichlids fishes, with other faunas receiving far less attention. This is currently being addressed, but many groups remain over looked. This is true of mastacemblids (spiny-eels), a secretive and cryptic fish group, for which almost nothing is known regarding their evolutionary relationships, ecology or behaviour. That these fish have a radically different life history and ecology from previously studied faunas, makes them an important system for cross-taxonomic comparisons, leading to a better understanding of whether there are common factors that have promoted the elevated levels of species richness in this lake and how this biodiversity is maintained. Aims & objectives 1. Generating genetic data, the student will establish species-level relationships for African spiny-eels, with particular focus on LT. Lake colonisation history will be tested through inclusion of non-LT species, while LT biodiversity will be assessed through multiple sampling. Results will then be compared to patterns reflected in other well-studied LT faunas, to determine generalities common to these systems. 2. Ecological niche segregation plays an important role in the divergence of some LT faunas. Using stable isotope signatures, and gut contents, the extent of differences in feeding strategies will be examined. The results of the genetic and ecological data can then be synthesised in the context of adaptive radiation theory. 3. A genetic study of a single LT spiny-eel species will test the extent of genetic differentiation between populations along the LT shoreline. Similar studies on cichlids fishes indicate that climatically driven fluctuations in lake level may be an important factor in speciation, but their influence on non-cichlid groups is unknown. This will link to the initial aim in investigating the degree to which environmental factors maybe driving speciation in LT. Applications & beneficiaries This project represents a new collaboration between researchers with complementary interests and expertise in evolutionary and environmental biology and within institutions providing an unparalleled combination of facilities and expertise relevant to the success of the proposed research. The project builds on the link provided by Ms Brown (named student), who conducted her M.Sc project with Dr Day, investigating molecular phylogenetics and dating for a marine fish group (examined by Dr Rüber) and awarded a high distinction. The student is an exceptionally promising scientist, who has a thorough and independent approach to research and who is perfectly suited to the proposed project. The project will provide a broad training in various evolutionary and ecological disciplines, requiring practical and analytical techniques that reflect the need of the CASE partner to collaborate. The project will not only compliment the skills already gained by the student (e.g. phylogenetics, systematics) during her NERC funded M.Sc and as a research assistant (molecular biology), but aims to build and expand upon this training (e.g. population genetics, ecology) to ensure she will be competitive in pursing a future research career. Results will be disseminated to the scientific community via publication in international journals, conferences, as well as to a non-scientific audience (e.g. NHMs public lecture series).