Wednesday, August 17, 2016

[PaleoOrnithology • 2016] Three Terrestrial Pleistocene Coucals (Centropus: Cuculidae) from southern Australia: Biogeographical and Ecological Significance; Centropus colossus, C. bairdi & C. maximus


Centropus phasianinus (Latham, 1801)

Centropus bairdi   C. maximus

Shute, Prideaux & Worthy, 2016 
  DOI:
 10.1111/zoj.12387  
theconversation.com

Abstract  

Coucals are large, predatory, primarily ground-dwelling cuckoos of the genus Centropus, with 26 extant species ranging from Africa to Australia. Their evolutionary and biogeographical history are poorly understood and their fossil record almost non-existent. Only one species (Centropus phasianinus) currently inhabits Australia, but there is now fossil evidence for at least three Pleistocene species. One of these (Centropus colossus) was described from south-eastern Australia in 1985. Here we describe additional elements of this species from the same site, and remains of two further extinct species from the Thylacoleo Caves of the Nullarbor Plain, south-central Australia. The skeletal morphology and large size of the three extinct species indicates that they had reduced capacity for flight and were probably primarily ground-dwelling. The extinct species include the two largest-known cuckoos, weighing upwards of 1 kg each. They demonstrate that gigantism in this lineage has been more marked in a continental context than on islands, contrary to the impression gained from extant species. The evolutionary relationships of the Australian fossil coucals are uncertain, but our phylogenetic analysis indicates a possible close relationship between one of the Nullarbor species and extant Centropus violaceus from the Bismarck Archipelago. The presence of three coucals in southern Australia markedly extends the geographical range of the genus from tropical Australia into southern temperate regions. This demonstrates the remarkable and consistent ability of coucals to colonize continents despite their very limited flying ability.

  KEYWORDS: Centropus bairdi; Centropus colossus; Centropus maximus;  coucals; Cuculidae; fossil birds; Green Waterhole Cave; Nullarbor; Pleistocene; Thylacoleo Caves 


Thunder thighs: The femur of a modern Pheasant Coucal Centropus phasianinus (left) looks puny next to the bones of the extinct Nullarbor species Centropus bairdi (middle) and Centropus maximus (right). 
photo: Elen Shute  theconversation.com


Conclusion

There is now compelling fossil evidence that Australia hosted an endemic radiation of coucals during the Pleistocene, and that the current limitation of the genus to northern/eastern Australia is relictual or the result of recent recolonization. Lack of local diversity in this genus must now therefore be explained in terms of extinction processes, but this requires a better understanding of the geographical and temporal distribution of the three Pleistocene species. Our data show that Pleistocene species loss in Australia's birds has been underestimated. We hope that future fossil finds will clarify whether the exceptionally large species discussed here were part of localized biodiversity ‘hotspots’, or whether the species turnover long observed in Australia's Pleistocene marsupial megafauna is matched in the avifauna on a continental scale.

  
Elen Shute, Gavin J. Prideaux and Trevor H. Worthy. 2016. Three Terrestrial Pleistocene Coucals (Centropus: Cuculidae) from southern Australia: Biogeographical and Ecological Significance.  Zoological Journal of the Linnean Society. 177(4); 964–1002.  DOI: 10.1111/zoj.12387 

The world's biggest cuckoos once roamed the Nullarbor Plain https://theconversation.com/the-worlds-biggest-cuckoos-once-roamed-the-nullarbor-plain-54050 via @ConversationEDU

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