Carabhydrus mubboonus, new species (Coleopiera; Dytiscidae; Hydroporinae) from small. closed, forest streams of the Great Dividing Range of northern Queensland. Australia, is described. A key to the five described species of Carabhydrus is presented. The systematic position of the genus Carabhydrus Watts is reviewed. Although it resembles members of the Bidessini Sharp in some characters, others indicate the genus belongs in the tribe Hydroporini Erichson (1837) and has affinities with the subtribe Sternopriscina Van den Branden, However, no clear synapomorphy was discovered that unequivocally identifies the sister taxon.