A case for realigning species limits in the southern Australian whipbirds long recognised as the Western Whipbird (Psophodes nigrogularis)

ABSTRACT

The Western Whipbird (Psophodes nigrogularis) has a highly disjunct west–east distribution across southern Australia. Earlier morphological analyses recognised four subspecies in one species: P. n. nigrogularis and P. n. oberon in south-west Western Australia, and P. n. leucogaster of the Eyre and Yorke Peninsulas and the Murray Mallee, and P. n. lashmari, restricted to Kangaroo Island, both in eastern Australia. Later morphological analyses elevated P. n. nigrogularis to monotypic species rank, and placed the remaining western and two eastern taxa as three subspecies of a second species P. leucogaster. Initial mtDNA analysis questioned both arrangements but could not include all taxa. We used mtDNA sequence data from all available specimens of the entire group (DNA extracted from cryo-preserved tissues, toe-pads and feathers; holotypes excepted) to derive a more stable view of species limits. The samples fell into two strongly divergent but geographically structured groups, completely reflecting the eastern and western components of the distribution. Thus we see merit in treating the two geographical groupings as two species, P. nigrogularis in the west and P. leucogaster in the east, each having two subspecies. Nuclear data could test whether the two western subspecies in particular are genetically isolated or currently exchanging genes.

KEYWORDS:

• Psophodes
• whipbird
• mtDNA
• systematics
• southern Australia

Acknowledgements

Funding for laboratory expenses and some fieldwork was provided by BHP Billiton’s Ravensthorpe Nickel project; we are grateful to Roy Teale of Biota Environmental Sciences, who facilitated provision of this funding. We thank the Australian Federation of University Women – Doreen McCarthy Bursary, Holsworth Wildlife Research Endowment and the Nature Foundation of South Australia for providing funding for vocalisation fieldwork. We would like to thank Joanna Sumner (Museum Victoria, Melbourne), Claire Stevenson and Ron Johnstone (Western Australian Museum, Perth), Steve Donnellan, Philippa Horton and Leanne Wheaton (South Australian Museum, Adelaide), Paul Sweet (American Museum of Natural History, New York) and Robert Prys-Jones (Natural History Museum, Tring) for providing and sampling museum specimens. Petter Zahl Marki and Roger Jaensch assisted with photography of an NHM specimen. Emily McGuire and Angharad Johnston assisted with vocalisation fieldwork and Prof. Sonia Kleindorfer provided guidance and advice on the analysis of vocalisations. David Stewart allowed us to use his recordings of Western Whipbirds held in the sound library of the Australian National Wildlife Collection. We thank Alex Drew and Margaret Cawsey (Australian National Wildlife Collection) for help with our assessments of vocalisations.

Supplemental data

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Additional information

Funding

This work was supported by BHP Billiton’s Ravensthorpe Nickel project; Australian Federation of University Women – Doreen McCarthy Bursary; Holsworth Wildlife Research Endowment; Nature Foundation of South Australia.