Abstract
Megapodes are unusual galliform birds that use passive heat sources to incubate their eggs. Evolutionary relationships of extant megapode taxa have become clearer with the advent of molecular analyses, but the systematics of large, extinct forms (Progura gallinacea, Progura naracoortensis) from the late Cenozoic of Australia has been a source of confusion. It was recently suggested that the two species of Progura were synonymous, and that this taxon dwarfed into the extant malleefowl Leipoa ocellata in the Late Pleistocene. Here, we review previously described fossils along with newly discovered material from several localities, and present a substantial taxonomic revision. We show that P. gallinacea and P. naracoortensis are generically distinct, describe two new species of megapode from the Thylacoleo Caves of south-central Australia, and a new genus from Curramulka Quarry in southern Australia. We also show that L. ocellata was contemporaneous with larger species. Our phylogenetic analysis places four extinct taxa in a derived clade with the extant Australo-Papuan brush-turkeys Talegalla fuscirostris, L. ocellata, Alectura lathami and Aepypodius bruijnii. Therefore, diversity of brush-turkeys halved during the Quaternary, matching extinction rates of scrubfowl in the Pacific. Unlike extant brush-turkeys, all the extinct taxa appear to have been burrow-nesters.
Highlights
Megapodes (Megapodiidae) are a family of galliform birds endemic to Oceania
The fossil specimens described below are referred to Galliformes and therein to Megapodiidae based mainly on features noted by Mourer-Chauviré [46], Worthy et al [17,21] and Mayr & Weidig [47]
There was high support for the fossil megapode genera that we identified in our morphological examinations: P. gallinacea and P. campestris formed a clade with 79% bootstrap support and La. naracoortensis and La. olsoni formed a clade with 92% support
Summary
Megapodes (Megapodiidae) are a family of galliform birds endemic to Oceania. Among birds, they do not use body-heat to incubate their eggs [1]. A few species do not build mounds, and bury their eggs in warm sand, using either geothermal heat from volcanoes or the heat of the sun for incubation [3], while some species in the genus Megapodius are flexible in their nesting strategies depending on environmental circumstances [4]
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