TY - JOUR T1 - On the Age and Origin of Lake Ejagham, Cameroon, and Its Endemic FishesAbstract JF - Quaternary Research Y1 - 2018 A1 - Curt Stager, Jay A1 - Alton, Kenneth A1 - Martin, Christopher H. A1 - King, David T. A1 - Petruny, Lucille W. A1 - Wiltse, Brendan A1 - Livingstone, Daniel A. KW - Africa KW - cameroon KW - Cichlid KW - Diatom KW - evolution KW - Lake Ejagham KW - Speciation KW - West African monsoon AB - Lake Ejagham is a small, shallow lake in Cameroon, West Africa, which supports five endemic species of cichlid fishes in two distinct lineages. Genetic evidence suggests a relatively young age for the species flocks, but supporting geologic evidence has thus far been unavailable. Here we present diatom, geochemical, mineralogical, and radiocarbon data from two sediment cores that provide new insights into the age and origin of Lake Ejagham and its endemic fishes. Radiocarbon ages at the base of the longer core indicate that the lake formed approximately 9 ka ago, and the diatom record of the shorter core suggests that hydroclimate variability during the last 3 millennia was similar to that of other lakes in Cameroon and Ghana. These findings establish a maximum age of ca. 9 cal ka BP for the lake and its endemic species and suggest that repeated cichlid speciation in two distinct lineages occurred rapidly within the lake. Local geology and West African paleoclimate records argue against a volcanic, chemical, or climatic origin for Lake Ejagham. Although not conclusive, the morphometry of the lake and possible signs of impact-induced effects on quartz grains are instead more suggestive of a bolide impact. VL - 895716332765461461671825961727356647223 UR - https://www.cambridge.org/core/product/identifier/S0033589417000370/type/journal_articlehttps://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033589417000370 IS - 01 ER -