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Australian Megafauna A-Z: C is for Centropus

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.

This is the pheasant coucal (Centropus phasianinus), the only living australian coucal species. Image source: Wikipedia.

This is the pheasant coucal (Centropus phasianinus), the only living australian coucal species. Image source: Wikipedia.

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.

A reconstruction of the giant coucal (Centropus colossus) feeding on a small lizard just in front of the sink hole whereits fossils where found. Image by Frank Knight, from Kadimakara.

A reconstruction of the giant coucal (Centropus colossus) feeding on a small lizard just in front of the sink hole whereits fossils where found. Image by Frank Knight, from Kadimakara.

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:

A is for Alkwertatherium

B is Barawertornis

Australian Megafauna A-Z: B is for Barawertornis

Just over a month ago I started a new series here on Blogozoic, the Australian megafauna A-Z, in order to show people the weird and wonderful products of the evolutionary and geographic isolation of Australia. In the first post of the series I wrote about Alkwertatherium, a large marsupial that roamed the Northern Territory in the Late Miocene. Now we move onto the letter B and this time the animal, somewhat appropriately, is a bird.

The group to which this bird belongs is the Dromornithids. Those of you with very good memories may remember I wrote a post giving an introduction to these giant, extinct, flightless birds back in February (click here to read it). This time however I will focus on one species of dromornithid in particular, the species in question is Barawertornis tedfordi.

A reconstruction of Dromornis stirtoni by the fantastic palaeo-artist Peter Trusler.

A reconstruction of the dromornithid Dromornis stirtoni by the fantastic palaeo-artist Peter Trusler.

Barawertornis tedfordi isamong the oldest known dromornithids, dating to the Late Oligocene to Early Miocene. Its generic name means ‘ground bird’ and it specific name is in honour of the vertebrate palaentologist Richard Tedford, who was one of the first people to collect dromornithid remains in Australia. The holotype, a partial left femur, was described along with other partial hind limb fragments and a dorsal vertebra by Vickers-Rich (1979). Little more was discovered of the taxon until 2010, when Nguyen and colleagues described multiple partial femora, tibiotarsi and tarsometatarsi from the Riversleigh World Heritage Area in north-western Queensland. This new material allowed the researchers to better understand the relationship of B. tedfordi to other dromornithids as well as make some inferences about how this animal may have lived.

Some of the new material described in 2010 by Nguyen and colleagues. You can see the fragmentary nature of the material, one of the joys of palaeo in Australia! Image from Nguyen et al. 2010.

Some of the new material described in 2010 by Nguyen and colleagues. You can see the fragmentary nature of the material, one of the joys of palaeo in Australia! Image from Nguyen et al. 2010.

As well as being one of the oldest dromornithid species, B. tedfordi is also the smallest known species of dromornithid and would have been similar in size to the extant southern cassowary (Casuarius casuarius), with an estimated mass of around 45 – 65 kg (Nguyen et al. 2010). Furthermore, the relative proportions of the hind limb bones in are also most similar to that of the southern cassowary, suggesting that it may have been capable of similar cursorial (walking and running) abilities. With Australia being mainly covered by forest during the Early Miocene it makes sense that B. tedfordi would have converged upon a similar physique to the cassowary that today still roams the forests of north-eastern Australia and Papua New Guinea.

Anyone who thinks birds aren't related to dinosaurs need to look at the cassowary. Barawertornis is thought to have lived in a similar manner to this modern day forest-dweller. Image from www.flickr.com.

Anyone who thinks birds aren’t dinosaurs need to look at the cassowary. Barawertornis is thought to have lived in a similar manner to this modern day forest-dweller. Image from http://www.flickr.com.

The phylogenetic position of B. tedfordi is also still not certain. Previous analyses (e.g. Murray & Vickers-Rich 2004) and the strict consensus of the analysis by Nguyen et al. (2010) found that B. tedfordi was the sister taxon to all other dromornithids. However, Nguyen et al. (2010) also found weak support for B. tedfordi forming a clade with Ilbandornis sp., I. woodburnei, Dromornis planei, and D. stirtoni. The fragmentary nature of most dromornithid material however prevents more definitive statements being made about their phylogenetic relationships at present.

The phylogeny on the left shows the currently accepted position of B. tedfordi. The phylogeny on the right shows the position that Nguyen et al. 2010 found weak support for. Images modified from Nguyen et al. 2010.

The phylogeny on the left shows the currently accepted position of B. tedfordi. The phylogeny on the right shows the position that Nguyen et al. 2010 found weak support for. Images modified from Nguyen et al. 2010.

So that’s B done, I’ll leave it up to you clever people to figure out what letter is coming next. Stay tuned…

References

MURRAY, P.F. & VICKERS-RICH, P., 2004. Magnificent Mihirungs: the Colossal Flightless Birds of the Australian Dreamtime. Indiana University Press, Bloomington, 410 pp.

NGUYEN, J.M.T., BOLES, W.E. & HAND, S.J., 2010. New material of Barawertornis tedfordi, a dromornithid bird from the Oligo- Miocene of Australia, and its phylogenetic implications. Records of the Australian Museum 62, 45–60.

Other posts in the Australian Megafauna A-Z series:

A is for Alkwertatherium

Australian Megafauna A-Z: A is for Alkwertatherium

This blog has been going for just over four months now and a couple of weeks ago I broke through the 2,000 hits barrier. Whilst that may be a drop in the ocean for some of the more popular blogs on the internet, the fact that my inane ramblings about palaeontology have been viewed over 2,000 times feels pretty cool and definitely spurs me on to keep writing the blog. So if you’re someone who’s been here before, thank you, I hope you’ve enjoyed my articles and will continue to do. If this is your first time here, welcome!

Now that there are least a trickle of people who read the blog on a semi-regular basis, I wanted to start the first regular feature on Blogozoic. Since I’m a palaeontologist (in training) working in Australia I thought that I should write a series of posts showing off some of Australia’s extinct beasties. So this is the first post in the Australian Megafauna A – Z. Every now and again there will be a new post covering an extinct megafauna taxon whose name begins with a different letter. I do also have an ulterior motive for doing this as it means I will become more familiar with the Australian megafauna whilst I write the series; having not grown up in Australia (I’m originally from Belfast, Northern Ireland and have lived in Melbourne for the past six years), I’m not as clued up on this group of animals as I would like to be.

Before I introduce the first species of the series, I’ll quickly define what I mean when I say Australian megafauna. They were a of group large animal species that existed in Australia until sometime in the Pleistocene. They weighed at least 30 kg, with the largest taxa weighing up to an estimated 2,000 kg! What exactly caused the Australian megafauna to go extinct is still the subject of very intense debate here in Australia, with research continually providing new perspectives on the matter (e.g. a PLOS One paper that came out last week showed via isotope analysis of kangaroo and diprotodontid teeth that southeastern Queensland in the late Miocene and Pliocene was less arid than previously thought, with tropical forests, wetlands and grasslands all present (Montanari et al 2013)). The Australian megafauna were comprised mostly of marsupials, but also contained reptiles and birds, some of which we’ll meet in subsequent posts. Let’s meet the first species in this series then shall we? The first taxon under the spotlight is Alkwertatherium webbi.

Alkwertathrium webbi is a zygomaturine diprotodontid known only from the Alcoota Local Fauna in Northern Territory. The diprotodontids were medium to large sized herbivorous marsupials that included the largest known marsupial, the rhino sized Diprotodon opatum (you may hear about it in a few posts time). There are two currently recognised sub-families of diprotodontids, the Diprotodontinae and the Zygomaturinae, of which A. webbi belongs to the latter. The two sub-families are distinguished mainly on the basis of differences in the structure of their third premolar.

Alkwertatherium webbi was a small zygomaturine, around the size of a horse. The holotype specimen, found at the famous fossil bearing site at Alcoota Station, includes a skull with lower jaws and measured just over 40 cm in length. The features of Alkwertatherium’s skull show similarities to several other zygomaturine taxa, causing confusion to those who have attempted to decipher its phylogenetic position. Some workers (Black and  Archer, 1997) have placed it within the Zygomaturinae, whereas Murray (1990), in the paper where he described the holotype specimen, suggested it was in fact the sister taxa to all other zygomaturines, a claim that would mean it was the sole survivor of this ancestral group due to its Late Miocene age. Mackness (2010) follows the placement of Black and Archer (1997), in addition to stating that the archaic features of Alkwertatherium support the view that the Zygomaturinae evolved from basal Diprotodontinae.

The holotype skull of Alkwertatherium webbi. Apologies for the crappy picture quality, this is a scan from Wildlife of Gondwana by Pat & Tom Rich.

The holotype skull of Alkwertatherium webbi. Apologies for the crappy picture quality, this is a scan from Wildlife of Gondwana by Pat & Tom Rich.

Despite not being as well-known as other extinct megafauna taxa, Alkwertatherium gives a glimpse into past diversity in Australia. That’s the first in the Australian Megafauna A – Z Series; stay tuned for more to come in the following months!

References

Black, K and Archer, M (1997) Silvabestius gen. nov., a primitive zygomaturine (Marsupialia, Diprotodontidae) from Riversleigh, northwestern Queensland. Memoirs of the Queensland Museum 41: 193-208.

Mackness, B (2010) On the identity of Euowenia robusta De Vis, 1891 with a description of a new zygomaturine genus. Alcheringa 34:455-469.

Montanari S, Louys J, Price GJ (2013) Pliocene Paleoenvironments of Southeastern Queensland, Australia Inferred from Stable Isotopes of Marsupial Tooth Enamel. PLoS ONE 8(6): e66221. doi:10.1371/journal.pone.0066221

Murray, PF (1990) Alkwertatherium webbi, a new zygomaturine genus and species from the late Miocene Alcoota Fauna, Northern Territory (Marsupialia, Diprotodontidae). The Beagle, Records of the Northern Territory Museum of Arts and Sciences 7: 53-80.       

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