Cymadusa filosa Savigny, 1818 Cryptogenic (= Grubia australis Barnard, 1916)

Weaving a nest out of algal fronds, this amphipod inhabits estuarine areas. It was first recorded from South Africa by Barnard (1916) based on specimens collected in 1913. He described it as a new species, Grubia australis, and later transferred it to the genus Cymadusa (Barnard, 1940); in turn, it was later synonymized with the older name Cymadusa filosa by J.L. Barnard (1955). Transport in algae on ships’ hulls appears to be the most probable vector. Once thought to be globally distributed, Cymadusa filosa, originally described from the Mediterranean (Egypt), has been shown to be a species complex (Peart 2004). South African material now bears re-examination to determine whether the stem species, the Mediterranean Cymadusa filosa, is in South Africa, or whether another species is involved.