Investigating Africa’s freshwater fish diversity through the lens of species description trends: How many species are there?

Abstract Africa hosts one of the world’s richest freshwater ichthyofaunas, yet major gaps persist in species diversity, distribution, and evolutionary knowledge. We compiled a comprehensive dataset of all valid African freshwater fish species described from 1758 to 2025 and analyzed taxonomic, biogeographical, authorship, and conservation patterns based on species description trends. Historical analyses revealed geopolitical signatures: description rates accelerated during late nineteenth-century European exploration, declined after mid-twentieth-century decolonization, and have partially recovered as African institutions strengthened their taxonomic capacity. Our logistic model predicts 9,964 freshwater fish species for Africa, indicating that over 6,600 remain undescribed. Species accumulation curves show marked heterogeneity among ichthyofaunistic provinces: the Congo basin exhibits the highest richness, whereas provinces such as the East Coast remain under-sampled, despite hosting numerous threatened species. Authorship data highlight persistent geographic asymmetries, with most species historically described by European and North American researchers. International Union for Conservation of Nature (IUCN) assessments indicate that 17.6% of evaluated species are threatened, notably among Cichliformes. Collectively, these results quantify Africa’s taxonomic impediment and identify priority regions, taxa, and institutional needs. Strengthening local taxonomic capacity, expanding integrative sampling (voucher, DNA, eDNA), and improving biorepositories and collaboration networks are essential for accelerating species discovery and supporting freshwater biodiversity conservation across the continent.