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.
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.
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.
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.
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:
Travis Park 