Time for another entry in my Australian megafauna A-Z series. We’ve previously looked at Alkwertatherium and Barawertornis. Both these taxa have come from the north of the continent, so I think it’s only fair we give some attention to fossils from the southern end of the continent this time around. This fossil bird species was found in a cave in the south-eastern corner of South Australia. Ladies and Gentlemen, C is for Centropus colossus, better known as the giant coucal.
Coucals are closely related to cuckoos and roadrunners (it’s a real bird not just a cartoon). They are also related to the enigmatic South American bird the hoatzin, although exact relationships are still being debated. This makes the group one of the earlier diverging lineages of modern birds (Edit: thanks to David in the comments and also me going and doing some further reading, coucals are not closely related to the hoatzin. Moral of the story, check your sources! Thanks for the heads up David!). Today in Australia there is one living species of coucal, the pheasant coucal. However, this taxon only lives in the northern forests of Australia and when the fossil species was found in the late seventies, it came as a bit of a surprise to discover this group so far south.
Centropus colossus was described based on an almost complete left humerus by Robert Baird in 1985. Its reduced muscle attachment points on the pectoral crest of the humerus suggest that it was flightless. Modern coucals only fly when disturbed, but the giant coucal was a third larger in size than the pheasant coucal and may therefore have been completely flightless. The presence of the giant coucal in what is today relatively arid country suggests that in the past this region had much more plant cover.
A similar issue has arisen with the discovery of fossil coucal remains from the Thylacoleo Caves in the Nullarbor Plain, south-central Australia. These remains, which are from an undescribed species of coucal were discussed in a talk at CAVEPS 2013 (the conference I recently attended, see here for my quick round up of the week) by Flinders University PhD student Elen Shute (also see this article for further info). The presence of the coucal indicates that this region was thickly covered in vegetation in the past, despite it being desert at present.
The generic name, Centropus, comes from two Latin words; centro, meaning spine and pus, meaning foot. This is referring to the characteristic elongate nail on the hallux of other taxa in the genus. The specific name refers to the fact that this species is larger than other taxa of this genus.
Well that’s C done, D will be a slightly better known animal, if not the best known of all the Australian megafauna. All will be revealed in the near future…
References
Baird, Robert F., 1985. Avian fossils from Quaternary deposits in ‘Green Waterhole Cave’, south-eastern South Australia. Records of the Australian Museum 37(6): 353–370.
Baird, R.J.F. 1985. Centropus colossus Baird 1985, The Giant Coucal, Pp. 205–208 in Vickers-Rich P., and Van Tets, G.F. (eds), Kadimakara, Extinct Vertebrates of Australia. Princeton University Press: New Jersey. 284 pp.
Clode, D. 2009. Prehistoric giants, the megafauna of Australia. Museum Victoria Nature Series, Melbourne, 72 pp.
Other posts in the Australian Megafauna A-Z series:
Travis Park 
The hoatzin is not specifically related to the coucals. Some people used to think it was a cuculiform, as the coucals indeed are – but it’s not.