New and little-known gnathiid isopod crustaceans (Cymothoida) from the northern Great Barrier Reef and the Coral Sea

Ten species of Gnathiidae (Crustacea, Isopoda, Cymothoida) including six new species, are reported from Lizard Island and nearby reefs, northern Great Barrier Reef and reefs of the Coral Sea (Chesterfield Reefs, Mellish Reef and Marion Reef): Gnathia wistari sp. nov. (Lizard Island region and Capricorn Group, southern Great Barrier Reef), Gnathia coralmaris sp. nov. (Mellish Reef), Gnathia varanus sp. nov. (Lizard Island group), Gnathia marionis sp. nov. (Marion Reef), Gnathia hamletgast sp. nov. (Chesterfield Reefs) and Elaphognathia australis sp. nov. (Chesterfield Reefs). New localities are reported for four other species: Gnathia aureamaculosa Ferreira and Smit, 2009 and Gnathia masca Farquharson and Smit, 2012 from Lizard Island and nearby reefs; Gnathia falcipenis Holdich and Harrison, 1980 and Gnathia variobranchia Holdich and Harrison, 1980 from Lizard Island, Wistari Reef, Heron Island and Chesterfields Reefs