Pinnularia is a genus of predominantly fresh-water diatoms, usually found in ponds and moist soil. They are elongated elliptical unicellular organisms. Their cell walls are composed chiefly of a rigid silica framework.
Living diatoms are among the most abundant forms of plankton and represent an essential part of the food chain in the ocean. Diatoms are responsible for at least 25% of global carbon dioxide fixation.
The species name honors the group Caprichoso, from the “Boi Bumbá” Folkloric Festival, Parintins City, Amazonas State, Brasil.
For the experts: While possessing a remarkable diversity in the acidic and oligotrophic waters of the Amazon basin, the genus Pinnularia appears underdescribed in the region. In this study, we present light and scanning electron microscopical observations on Pinnularia caprichosa sp. nov. from Tupé Lake, a dendritic lake located on the floodplain of the Negro River basin. This new taxon has a large axial area and transapical striae that are slightly radiate to parallel and longer in the middle portion of the valve. The species was compared with Pinnularia elliptica, P. instabilis, P. lacunarum, P. montana, P. permontana and P. subflexuosa, all of which closely resemble P. caprichosa but differ from the new species in specific details of size, striae density and valve shape.