What do we know about the harvestmen (Arachnida: Opiliones) from Paraná State, Brazil? A diversity hotspot in the southern Atlantic Forest

. The knowledge of the diversity and distribution of Opiliones in Brazil can be considered suitable. However, while the harvestmen fauna of the southern Atlantic Forest is also well-known, several gaps remain and they are still far from complete, notably those in Paran & aacute;. Thus, investigations on regional assemblages focused on primary data are critical for promoting many key research fields such as taxonomic and phylogenetic studies, as well as encouraging conservation efforts. This study provides a comprehensive overview of the knowledge on diversity, distribution, and the history of Opiliones research from the state of Paran & aacute;. Knowledge gaps are identified and the background of taxonomic studies, highlighting the key contributors, is also discussed. A total of 1115 records were compiled, with 584 from Paran & aacute; for 118 species belonging to five families. This compilation allowed to identify 60 endemic species and 106 type localities (including invalid specific names) for the state. Despite being one of the three Brazilian states with the greatest diversity of harvestmen, this knowledge is concentrated in a small region in the First Plateau and is the result of the efforts of a few researchers and collectors over a few decades. To overcome these limitations further sampling is required in the state's western region. This study is a very first step toward to achieve a comprehensive database of knowledge about Opiliones from one of the richest hotspots for these invertebrates in the world. We encourage similar approaches that consider the state of art for other research fields such behavior, ecology, and natural history in the state, as well as to other neotropical areas.