Occurrence of lungfish in the Brisbane River, Queensland, Australia dates back to 3850 yr BP

Abstract

Bone fragments collected from the Platypus RockShelter in southeast Queensland, on the banks of the Brisbane River, can be compared with bone from the living Australian lungfish, Neoceratodus forsteri, and suggest that this species, which was widely distributed in Queensland in Pliocene and Pleistocene deposits, was also found in the Brisbane River as recently as 3850 years before the present, based on current 14C dates. The fragments have dimensions and morphology consistent with parts of lungfish jaws and palatal bones, and differ from the bones of teleost fish of comparable size that live in the Brisbane River. Unfortunately, attempts to extract mitochondrial DNA from the bones have not been successful due to very low levels of endogenous DNA. The presence of morphologically identifiable lungfish bones suggests that the Brisbane River has, and always did have, a population of lungfish that belong in this river and were not translocated. The Brisbane River is separated from the Mary and Burnett Rivers by mountain ranges, and the Rockshelter is 90 km away from the nearest tributary of the Mary River. Using a morphological analysis of carbon-dated midden site skeletal material, we show that lungfish were present in the Brisbane River over three thousand years ago, and may always have been there, despite attempts to translocate lungfish to this habitat. This finding is significant because lungfish are now seriously at risk in all of their present habitats from human interference in the environment and the resulting loss of biodiversity. Confirmation that the Brisbane River contains a population of lungfish, and always has done, increases the need for protection of this endangered species.