Revision of Macroponema Mawson, 1978 (Nematoda: Strongylida) from macropodid marsupials with the description of two new species

Abstract

Abstract Background Species of Macroponema Mawson, 1978 are strongyloid nematodes which occur in the stomachs of macropodid marsupials in Australia. In this study, the genus Macroponema is revised, redescriptions of the two known species are provided, and two new species are added to the genus. Methods A molecular characterisation of the internal transcribed spacers of the nuclear ribosomal DNA of representative specimens of Macroponema from all known host species was undertaken to confirm the status of M. cf. comani. This resulted in the identification of a further new species within the genus. Consequently, a review of all available material in museum collections was undertaken. Results The two known species M. beveridgei Mawson, 1978 from Osphranter antilopinus (Gould) and O. robustus (Gould), and M. comani Mawson, 1978 from Macropus giganteus Shaw are re-described and their geographical distributions expanded. Two new species added to the genus are M. arundeli n. sp. from Ma. giganteus found in Queensland and the north east of New South Wales, and M. obendorfi n. sp. from O. antilopinus and O. robustus in the Northern Territory, the Kimberley Division of Western Australia and eastern Queensland. The latter species was formerly identified as M. cf. comani based on molecular studies. The specific identification of both of the new species is supported by ribosomal DNA sequence data. Conclusions Based on the morphological and molecular characterisation of nematodes, this study has revealed the existence of four species within the genus Macroponema. The current phylogenetic data suggest that Macroponema spp. plausibly evolved by host switching; however, further studies are required to test this hypothesis.