Historical Biogeography Of Fishes Of The Fouta Djallon Highlands And Surrounding Areas
The purpose of this study is to elucidate the historical processes that have impacted the fishes of the Fouta Djallon highlands and surrounding areas. This mountainous region in Guinea, West Africa, lies on the northern edge of the Guinean Range. This geologic formation, of Jurassic origins, has long reported to serve as a barrier to dispersal in the region. These highlands currently separate two ichthyo-provinces in the area. The upper-Guinean province encompasses rivers on the Western slopes of the range that flow directly into the Atlantic Ocean. The Nilo-Sudan province is comprised of the rivers and streams on the Eastern slopes of the Guinean Range. These rivers flow west or north through the Sahel and eventually back to the Atlantic Ocean. While these highlands clearly serve as a barrier to dispersal for most fish taxa, some taxa are reported to occur on both sides of the Fouta Djallon. This study investigates three groups of these â€œamphi-Guineanâ€ taxa to determine if the same taxa are present within both provinces and what processes would have allowed for this dispersal to take place. In addition to the biogeographical questions addressed within the Fouta Djallon region, specimens from the surrounding areas are included to further understand the historical biogeography of these groups in West Africa. This study revealed the presence of numerous undescribed species within the Amphilius, Chiloglanis, and â€˜Barbusâ€™ groups investigated. While some taxa do appear to be amphi-Guinean others are restricted to one ichthyo-province or the other. Numerous headwater capture events within the area have allowed taxa to expand ranges and diversify. This study also provides insights on areas of endemism within the region where additional undiscovered diversity is likely to occur.