Weekly Wonders: Bullockornis

12 11 2009

Good tidings and well-wishes!

Nick-naming prehistoric animals seems to largely fall into the hands of Cenozoic paleontologists. After-all, while most people would be more likely to recognize the name ‘wooly mammoth’ over its scientific title of Mammuthus primigenius, no such cognomen has been bestowed upon Tyrannosaurus rex despite the efforts of Bill Watterson as shown in this now-infamous strip:

They don't make comics like this anymore...

Similarly, you’d be hard pressed to locate a layperson whose familiarity with Smilodon fatalis exceeds that of the ‘saber-toothed cat’. However, in my humble opinion, no paleontological pseudonym can compete in terms of sheer awesomeness with that which has become associated with Bullockornis planei: also known as (are you ready for this?)…”THE DEMON DUCK OF DOOM!!!”

(Note: anybody who can tell me who coined this gets a cookie!)

The owner of this insanely-cool distinction is a member of the Dromornithidae, a group of large, flightless birds which wandered throughout modern-day Australia from the Oligocene to the Pleistocene (although the earliest known fossils of these great birds hail from the Miocene, fossilized footprints suggest that they debuted in the previous epoch). In “Dinosaurs of the Air: The Evolution and Loss of Flight in Dinosaurs and Birds”, author and artist Gregory S. Paul writes:

“Long thought to be small-headed ratites, the robust dromornithids, or mihirungs, of Australia were actually big-headed neognathes, probably related to the duck group. The dromornithids had exceptionally large heads for birds, up to nearly half a meter in Dromornis [(the name-giving genus)]. Dromornis was also about as heavy as the moa and elephant birds… and other dromornithids were as small as emus.”

A flock of Bullockornis statues.

While the sheer size of these birds is indeed quite remarkable (Bullockornis itself stood approximately 2.5 meters in height), the vast majority of the scientific inquiry surrounding them concerns their diets. Peter F. Murray and Patricia Vickers-Rich have observed in their definitive volume on these animals entitled “Magnificent Mihirungs: The Colossal Flightless Birds of the Australian Dreamtine” that:

“The beaks of the larger mihirungs, Bullockornis planei and Dromornis stirtoni, were only recently discovered. The upper mandibles of these forms are deep, with a strongly arched culmen like that of the famous Eocene Euramerican giant ground bird Diatryma gigantea… Although enormous in isolation, the mandibles of Bullockornis planei and Dromornis stirtoni are not especially large in proportion to their bodies. A 50-cm long skull is impressive by itself, but connected to a 2.8-m tall, massively built  skeletal frame, it looks about average with, if not somewhat smaller than, the relative head-body proportions of a typical living anseriform bird.”

Gastornis (the currently accepted name for Diatryma) itself is quite controversial with regards to its suspected dietary preferences, with some paleontologists arguing that it was a fearsome predator (as seen in the BBC special ‘Walking With Prehistoric Beasts’), others maintaining that it was a strict herbivore which may have used its enormous beak to crack large nuts and seeds, and still others suggesting that it was an omnivorous generalist, all of which have been suggested as lifestyles for large dromornithids as well.

Bullockornis skull

However, the debate concerning the mihirungs has been complicated by an analysis of Genyornis eggshell isotopes which, according to Paul, “indicates that they were browsers… Murray and Megiran came to the same conclusion on the basis of their examination of skull structure.” Despite this, Australian paleo-ornithologist Stephen Wroe argues in this article that:

“Recent evidence, based on the relative proportions of different carbon isotopes present in fossil eggshells, has been interpreted as supporting the hypothesis that Genyornis was primarily a browser. However, in arriving at this conclusion the authors have assumed, a priori, that the bird was a herbivore. If we dismiss this assumption, as we must until more conclusive evidence comes to hand, then these data could just as easily support the proposition that Genyornis fed largely on browsing herbivores. Consequently, I conclude that isotopic evidence lends nothing to either pro-herbivory or pro-carnivory arguments at present.”

It should also be noted that Genyornis sported a significantly more gracile skull than either Bullockornis or Dromornis.

I also couldn’t resist mentioning that everyone’s favorite extinct varanid quite likely devoured these birds on occasion, though this is admittedly a speculative suggestion.

At any rate, regardless of what fodder Bullockornis and its relatives relied upon for their survival, nobody can deny that these avian giants were certainly highly intriguing beasts, but then, what else would you expect from Australia?

May the fossil record continue to enchant us all!




2 responses

16 11 2009

Yes, dinosaurs may have cooler sounding scientific names then Cenozoic critters (though i find many Cenozoic scientific names have a sort of poetic ring to them), they have cooler common names. In that same line of thought, people will also recognize that annoying surname “saber-tooth tiger”.

And that lizard mentioned is one of my favorite prehistoric animals. Australia has some truly fantastic fossil fauna. Too bad we don’t see much of them over here. Best i have come is a Diprotodon skull at the Smithsonian and a cast of Dromornis at the Burke Museum of Natural History in Seattle, WA.

16 11 2009

I’ll readily agree with you on both points: Australian fauna has always been truly amazing, yet it’s frustratingly difficult to locate any fossil specimens here in the states.

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