Picozoa

Picozoa is a phylum of tiny marine single-celled eukaryotes, each smaller than about three micrometres across, that live by feeding on organic particles rather than by photosynthesis. The group was first detected in 2007 from ribosomal RNA gene sequences in plankton samples from the North Atlantic and the Mediterranean, and it was first called the picobiliphytes because the cells seemed to carry phycobiliproteins, pigments known from red algae. Two studies in 2011 found no sign of photosynthesis, and in 2013 the group was formally described as a phylum of heterotrophic nanoflagellates with a feeding organelle and unusual movement. The phylum currently holds a single named species, Picomonas judraskeda, and its closest relatives are thought to be the red algae within the Archaeplastida, although that placement is still uncertain.