Six closely related species of the Copidognathus gibbus group (Acarina : Halacaridae) from north-eastern Australia

During a survey of the halacarid fauna of the Great Barrier Reef and reefs of the Coral Sea 70 species of Copidognathus were collected, among them 31 species of the gibbus group. Five new and closely related species in this g roup, namely C. aenigmatus sp. nov., C. asketus sp. nov., C. seductus sp. n ov., C. squarrosus sp. nov. and C. thompsoni sp. nov., are described. C. ca naliculifer is also recorded from the Great Barrier Reef. The holotype and paratype of this species are found to differ and the consequences of this o bservation are discussed. C. canaliculifer plus the five new and three prev iously described species are found to form an easily recognizable group tha t is characterized by wide and densely punctate idiosomal plates and a seri es of arched dorsolateral striae.