Abstract
Species belonging to the genus Laonice (Polychaeta: Spionidae) from continental shelf and slope depths off western and northern Australia are described. Three species are new to science (L. lemniscata, L. insolita, L. pectinata), two additional species of uncertain identity are recognised from incomplete material and are similar to existing species. A key is provided to allow identification of all six Laonice species known from Australia. Also, a new standard for the observation of hooded hooks in Laonice is established. One of the Australian species, L. quadridentata, belongs to a group of Laonice species with fused prostomium and peristomium. These species are of great morphological similarity and several are reported to exhibit ontogenetic and individual variability and we discuss the significant taxonomic problems that are a consequence of that variability. The faunas of the continental margin of western and northern Australia were poorly sampled prior to the extensive surveys that generated our study material; this study and other current work suggests that our present estimates of species richness of the Australian marine invertebrate fauna significantly underestimate species richness, perhaps by as much as 50%.
NSTL