Mediolabrus comicus
Mediolabrus comicus, known previously as Minidiscus comicus, is a species of nanophytoplanktonic centric diatoms within the family Thalassiosiraceae. Its cells have diameters as small as 1.9 μm, which makes M. comicus one of the smallest known diatoms and brings it near to the theoretical lower size limit for photosynthetic eukaryotes.