Abstract
Cyclotella katiana sp. nov. is described from La Reina Swamp, Parque Nacional Natural Los Katios, Colombia. Studied samples were collected from the stomach contents of Prochilodus magdalenae (Bocachico), an iliophagous fish species. The new taxon is distinguished from the related taxa C. atomus Kutzing, C. meneghiniana Kützing, and C. meduanae Germain, by the central valve face slightly undulated, the lack of fultoportulae in the valve face, the fultoportulae opened on every 2nd or 3rd interstriae and mantle spinulae at the valve face/mantle junction ever present. Also in the samples two other similar Cyclotella taxa were found; they were compared with the species above mentioned and with C. atomus var. gracilis Genkal & Kiss.