Where ichthyofaunal provinces meet: the fish fauna of the Lake Edward system, East Africa

Cycles of fusion and fission enabled rapid parallel adaptive radiations in African cichlids

Although some lineages of animals and plants have made impressive adaptive radiations when provided with ecological opportunity, the propensities to radiate vary profoundly among lineages for unknown reasons. In Africa's Lake Victoria region, one cichlid lineage radiated in every lake, with the largest radiation taking place in a lake less than 16,000 years old. We show that all of its ecological guilds evolved in situ. Cycles of lineage fusion through admixture and lineage fission through speciation characterize the history of the radiation. It was jump-started when several swamp-dwelling refugial populations, each of which were of older hybrid descent, met in the newly forming lake, where they fused into a single population, resuspending old admixture variation. Each population contributed a different set of ancient alleles from which a new adaptive radiation assembled in record time, involving additional fusion-fission cycles. We argue that repeated fusion-fission cycles in the history of a lineage make adaptive radiation fast and predictable.

The non-Haplochromis fish fauna in Uganda: an update on the distribution and a review of data gaps

Freshwater fishes are the second most threatened group of vertebrates after amphibians. In most developing countries, the conservation of freshwater fishes is largely hampered by limited information and data. The Red List assessments by the International Union for Conservation of Nature (IUCN) provide a benchmark for monitoring and mitigating species extinction risk, but these assessments require, inter alia, quantitative information on the species range in the wild. This information is largely missing for many species that face extinction threats. Here, we combine species occurrence data, expert knowledge, and literature to (i) review and update the distribution of non-Haplochromis fish species native to Uganda and (ii) determine the national geographical range of these fish species relative to their global range. For the latter, we use the IUCN's standard protocol for mapping distribution of freshwater species from which we derive both the national and global extent of occurrence (EOO) and area of occupancy (AOO). We show that at least 110 non-Haplochromis species occur in Uganda, with the majority species having a wide distribution outside the national boundaries. However, substantial gaps exist in data on presence of the species in their native range, where more than 60% of the species are designated as "possibly extant." We elaborate on fish species previously believed to occur in Uganda, e.g., Amphilius kivuensis Pellegrin, 1933; Bagrus degeni Boulenger, 1906; Marcusenius macrolepidotus (Peters, 1852); Petrocephalus catostoma (Günther, 1866); and Lacustricola pumilus (Boulenger, 1906), but where recent studies suggest they lack a native distribution within the country. In addition, we highlight fishes with occurrence records that site them in areas beyond their previously known range, requiring further investigations to ascertain their present status. This work has potential to (i) trigger evidence-driven policies aimed at site-based conservation and rethinking of extent of protected areas, (ii) stimulate data collection, especially in areas where fishes are designated as "possibly extant" and "presence uncertain," and (iii) aid the IUCN Red List assessments, for which conservation status of the majority non-Haplochromis species is outdated and many others remain unevaluated due to lack of quantitative information on their range.