Abstract
Aliaporcellanaspongicolasp. n. from the Philippines and Indonesia is described. The new species has been frequently photographed by divers because of its striking coloration, but has not been described yet. Aliaporcellanaspongicolasp. n. is in fact a widespread commensal of barrel sponges of the genus Xestospongia and other sponges. Morphological characters and ecological information of all described species of Aliaporcellana, and of other porcellanids associated with sponges and soft corals, suggest that all members of the genus are commensals, and that similar morphological adaptations to dwelling on these hosts have evolved independently in different evolutionary lines within Porcellanidae.