Two new freshwater crayfishes (Decapoda: Parastacidae) from Whitsunday Island, The Coral Sea, Australia

Abstract

Two new species of the crayfish genus Cherax are described from Whitsunday Island in the Coral Sea, Cherax austini sp. n. and Cherax cid sp. n. These two island species are similar to the 'C. depressus' species group from the Queensland mainland, differing in spination of the chelipeds and the development of the rostral ridges and sternal keel. Remarkably, Cherax austini sp. n. displays faint development of a median ridge on the cephalon, a feature otherwise associated with the disjunct and phylogenetically distinct fauna from the extreme south-west of Western Australia. Genetic analyses supported the close relationship of these two new species to the 'C. depressus' group from the mainland, with a comparatively recent divergence event between these two island species.