Micranurida pygmaea is a tiny species which reaches 0.6 mm in length. It is probably widely-distributed although under-recorded due to its small size. Micranurida pygmaea is white to bluish-grey in colour, has no anal spines and the furca is absent. The eyes are composed of 2+2 ocelli (sometimes reduced to 1+1 according to the literature, although all the specimens I have seen have 2+2) and the post-antennal organ (PAO) is circular with between six and eight lobes (Figs. 1, 2).