A new species, Aulacocyclus yorkensis sp. nov., is described from Cape York Peninsula, Australia. This species is similar to A. teres Percheron, these two being the largest Aulacocyclus in Australia, but they can be distinguished by the shape of the central tubercle and the pattern of pubescence on the mentum and metasternum. Additionally, illustrations of the new species and a key to the identification of the species of Aulacocyclus of Australia are provided.