Physiological, ecological and evolutionary studies of Scaptodrosophila hibisci have led to recognition of a second species in the Northern Territory (Australia) which is described here as Scaptodrosophila aclinata n.sp. The new species is readily distinguishable by reference to the first orbital: it is large and proclinate in S. hibisci and small and reclinate in S. aclinata. Scaptodrosophila hibisci has been collected from the flowers of five Hibiscus species in eastern Australia and S. aclinata uses eleven Hibiscus species in the Northern Territory. Only H. meraukensis is a host for both, and there is no evidence of narrow host-specialization. The distributions are apparently disjunct. The two species can be reared in the laboratory on cultured plants. Hybridization studies showed the two species to be partially interfertile; S. aclinata has delayed sexual maturation and extended copulation latency when compared to S. hibisci. This species pair is already the subject of various eco-physiological and reproductive-biological studies because of so many useful experimental attributes: they are interfertile and can be laboratory-cultured, their hosts and reproductive biology are known, they are abundant and easy to find, and research is underpinned by extensive genetic information already available for Drosophila.