Leptachirus, a new soleid fish genus from New Guinea and northern Australia, with descriptions of eight new species

WA Museum Records and Supplements | Updated 7 years ago

ABSTRACT – Leptachirus is described as a new genus of Soleidae for Aseraggodes klunzingeri (Weber) and eight new species from fresh or brackish water habitats in southern New Guinea and northern Australia formerly identified as A. klunzingeri. Leptachirus is differentiated from Aseraggodes, all species of which are marine, by its more slender body (depth 2.7-3.55 in SL), the corner of its jaws exposed on the cheek, usually 3 or 4 pelvic rays, shorter pelvic fins, each usually with 3 or 4 rays, and different pattern of its cephalic lateralis sensory system. The type species, L. alleni, is from the Bintung River, New Guinea; L. bensbach, L. kikori, and L. lorentz are named for the rivers in New Guinea in which they were collected; L. robertsi is from the Fly River in Papua New Guinea; L. darwinensis, very similar to L. bensbach, from the East and South Alligator Rivers and the Adelaide River of the Northern Territory of Australia; L. polylepis, with a high lateral-line scale count of 103-111, from the East, West, and South Alligator Rivers and the Mary River; and L. triramus from the Victoria River of Northern Territory and the nearby Ord River of Western Australia. The last species is the most divergent, having three instead of two branches of the lateral line on the ocular side of the head, and the pelvic fin of that side attached to the genital papilla. The holotype of L. klunzingeri Weber, described from one specimen collected in the mouth of the Merauke River, New Guinea, has been lost. Weber's illustration shows a fish with a deeper body and broader interorbital space than the other eight species. Additional species of Leptachirus might be expected from other rivers of New Guinea and northern Australia are better collected.