 The Williams' mud turtle is restricted to Lake Victoria and other lakes, rivers, and swamps in the upper Nile basin.Lake Victoria formerly was very rich in fish, including many endemics, but a high percentage of these became extinct during the last 50 years.The main group in Lake Victoria is the haplochromine cichlids ("Haplochromis" "sensu lato") with more than 500 species, almost all endemic, and including an estimated 300 that still are undescribed.