An Overview of the Tabanidae (Diptera) of Uruguay

The Tabanidae fauna of Uruguay has historically received limited attention, with most records dating from the 19th and early 20th centuries and concentrated near Montevideo. Here, we provide an updated synthesis of the Uruguayan Tabanidae fauna based on a comprehensive review of the literature, examination of historical material, recent field surveys, and validated records from citizen science. We recognized 52 valid species in 15 genera and six tribes, representing approximately 1% of the world diversity of the family. Four species are currently considered to be endemic to Uruguay. Since the last national revision, species richness has increased by 12%, largely through overlooked bibliographic records, the re-examination of museum specimens, and new distributional data. The fauna is dominated by the subfamily Tabaninae, particularly the tribes Diachlorini and Tabanini, whereas Pangoniinae is poorly represented. Males are described for 62% of the species, but immature stages are known for fewer than 20%, highlighting significant gaps in knowledge. Distributional data reveal a strong spatial bias: nearly half of the species are known from a single department, and four departments still lack records. A comparison with the Brazilian Pampa suggests that only slightly more than half of the species are shared, indicating that the regional fauna remains incompletely documented. Primary-type specimens are predominantly housed in European institutions, reflecting the historical development of Neotropical dipterology and the absence of resident specialists. Overall, our results suggest that the apparent modest diversity of Uruguayan Tabanidae likely reflects historical sampling bias, rather than true faunal impoverishment. Expanded field surveys and integrative taxonomic approaches are essential to clarify species limits, document immature stages, and better understand the biogeography of horse flies in the Pampa biome.