Epilithic diatoms (Bacillariophyceae) in a tropical Andean River of Southwest Colombia

Abstract In tropical regions there are a large number of species of diatoms that have not been identified yet. This research aimed to study the composition of epilithic diatom flora found in samples collected in Dagua River a tropical Andean hydrographical basin located to the southwest of Colombia. Samplings were performed in three stations with their respective three replicas between January and April 2018 to collect samples for identification of diatom (Class Bacillariophyceae). These samples were analyzed with light microscopy and interferential contrast microscopy. The results indicated the occurrence of 18 taxa distributed in 9 families and 11 genera. Two of these are new records for Colombia: Navicula incarum and Fragilaria aff. socia. The most species-rich genera was Navicula. A comparison with the diatom flora of the region shows that 9 species were recorded in common with the Cali River.