Phelloderma oxychaetoides sp. nov. is a remarkable new species from the deep Weddell Sea, bearing abundant oxychaetes (onychaete-like microxeas), morphologically distinct from the onychaetes of Tedania spp. collected in the same area. We give a redescription of the holotype of P. radiatum Ridley & Dendy, 1886, the type species of Phelloderma. We recognize three and a possible fourth species in Phelloderma: P. flava (Le´vi, 1993); P. oxychaetoides sp. nov.; P. polypoides Whitelegge, 1906; and P. radiatum Ridley & Dendy, 1886. An identification key for the species of Phelloderma is proposed. A discussion on the affinities of Phelloderma to both Mycalina and Myxillina is offered, and the current preference for the latter is further supported by the marked similarity between the oxychaetes of Phelloderma oxychaetoides sp. nov. and those of Chaetodoryx spp. (Coelosphaeridae, Myxillina).