Sea spiders (Pycnogonida, Arthropoda) from the Great Barrier Reef, Australia: new species, new records and ecological annotations

Thirty-three species of tropical shallow-water pycnogonids are reported from the Queensland coast, and coral reef habitats of the Great Barrier Reef and the Coral Sea. New species in the genera Austrodecus, Anoplodactylus and Pycnogonum are described, and 14 species not previously recorded for Australia are reported. All the families except Rhynchothoracidae are represented in this collection and rare species such as Rhopalorhynchus tenuissimum and Nymphopsis acinacispinata among others are reported for tropical Queensland for the first time. Anoplodactylus appears as highly diverse with eight species found in the area. The intertidal green alga Cladophora prolifera supports a rich pycnogonid fauna shown by a total of 14 species found in the alga at two different sites. On coral reefs, microhabitats such as coral rubble, macroalgae and zoanthids seem to shelter conspicuous pycnogonid populations. Pycnogonid fauna from tropical Queensland is related to the Indo-west Pacific zoogeographical region also including pantropical species. This study highlights the diversity of pycnogonids in shallow-water habitats and contributes to the knowledge of tropical faunae. It includes illustrations and descriptions for relevant records and emphasizes the strong need of taxonomic and phylogenetic revision of some of the major taxa.