If Dinosaurs survived in Australia...

Majin Gojira · Post by **Majin Gojira** » 2006-03-16 11:31pm

Suppose that, through some lucky accident: Dinosaurs remain the dominant species on the Australia/Antartica continent (Marsupials still get there, but they don't leave that landmass for some reason).

How do you think the various species would adapt through the ages to Australia's climate changes?

What dinosaurs would fill what niches in the modern day?

Would any Megafauna/any dinosaurs at all survive humanity's first arrival on the island?

The Second?

What would the reaction be by the
a) Aboriginies?
b) White Explorers?

And, if they manage to survive to the present day, would their be any "global" or continental changes in Australian culture? How would it effect history?

Yes, I am aware of how fragementary most of the fossil material is for Australian Dinosaurs--they've got Throwbacks (Labarythnadon't amphibians and Diictodont Mammal-like Reptiles), Advanced creatures (Dromeosaurs, Protoceratopcians, llyellinasaura) and dwarfs (Allosaurus, Minmi).

Usefull Links
Australian Prehistory
Fossils from Oz

Before saying "We don't know what 65 million years of evolution would do!?" remember, this is Australia--they've got lots of living fossils there already. Second: Speculate! Have fun with it!

Post by **Sea Skimmer** » 2006-03-16 11:46pm

Odds are no dinosaur, at least no large ones, could survive today because the world had a higher oxygen percentage in its atmospheric 65 million years ago. That’s also why no really giant land animals evolved to replace them. If a bunch of small ones are running around, well given all the other unusual stuff in Australia I doubt it would change anything.

Molyneux · Post by **Molyneux** » 2006-03-16 11:53pm

Read Marvel 1602; it's got dinosaurs in North America.

Darth Raptor · Post by **Darth Raptor** » 2006-03-17 12:37am

Sea Skimmer wrote:Odds are no dinosaur, at least no large ones, could survive today because the world had a higher oxygen percentage in its atmospheric 65 million years ago. That’s also why no really giant land animals evolved to replace them. If a bunch of small ones are running around, well given all the other unusual stuff in Australia I doubt it would change anything.

The average dinosaur was the size of a sheep, and oxygen concentrations are not the limiting factor on dinosaur size. The giant sauropods of the Jurassic got that large because they needed that much intestine to digest the tough plant matter they pretty much swallowed whole. Once you have teeth and rumination, herbivore sizes shrink exponentially. And there most certainly were mammals who evolved to occupy the vacant "giant herbivorous dinosaur" niche. Specifically amongst the rhinoceras family.

Australia is so isolated that I would imagine dinosaurs would be flourishing there all the way up the arrival of white explorers. They probably wouldn't be very large or dinosaur-like, however. Herbivore niches would most likely be held by medium-sized descendents of the iguanodontidae, and preyed upon by allosaurs. 65 million years is simply too vast a stretch of time to extrapolate beyond that, however. Needless to say, the human interactions would be... interesting.

Xon · Post by **Xon** » 2006-03-17 12:49am

The Aboriginies probably would hunt them to dead, as well as the destruction of the interia forests due to thier tactics of starting large fires to kill 1 or 2 animals.

Post by **weemadando** » 2006-03-17 01:09am

Yeah, the aboriginals did a good job of wiping out Australian megafauna in a few short millenia not to mention permanently altering the ecosystem through the massive burnoffs.

The only reason that they can say now that they are in tune with the fucking wild is because they destroyed anything that didn't fit with their unique interpretation of "in tune".

Xon · Post by **Xon** » 2006-03-17 02:17am

And if any dinos did survive, well Britain of the time period did like thier big game hunts.

Darth Raptor · Post by **Darth Raptor** » 2006-03-17 04:49am

Assuming the original Aboriginal incursions even gained a foothold...

Anarchist Bunny · Post by **Anarchist Bunny** » 2006-03-17 11:24am

Well, I don't think chicken or dog fights would be nearly as popular.

Zero · Post by **Zero** » 2006-03-17 11:35am

If dinosaurs had survived in Australia, would they really have been so isolated that they wouldn't have affected the environment elsewhere?

wolveraptor · Post by **wolveraptor** » 2006-03-17 02:04pm

There are dinosaurs in Australia. If you mean non-avian ones, then we have an interesting question. Australia is pretty nutrient-poor, which is why ectotherms held and still hold a formidable grip on the ecosystem; they're more efficient in low-energy situations than endotherms. Smaller animals also do well. The largest animals the continent has ever had were 2-3 tonne rodents, in contrast with 7-8 tonne mammoths and elephants almost everywhere else.

Gregory S. Paul says in Predatory Dinosaurs of the World that stiff-bodied, bird-like dinosaurs fare poorly in the world of small terrestrian animals because they, unlike mammals, are not supple-bodied. One thing I've seen that seems to support this is the increasing number of mammals being found to play in important ecological role in the small omnivore or insectivore niche. Dinosaurs seem unable to fill this position. Because of this, I'm not sure what would occur in Australia, where many animals are modestly-sized. Mammals would still have a powerful hold there, and dinos would probably fill the niches of tasmanian devils, dingos and kangaroos.

Majin Gojira · Post by **Majin Gojira** » 2006-03-17 03:15pm

Going through some searching, I deduced that the only mammals to survive in austrailia would be, on average, half a meter or smaller in body size. This would mean, if they were to develope similar to what we have in reality, the following native mammals would likely still be around in Australia (Generalized).

Bandicoots
Platypus
Echidna
Numbat
Quolls
Marsupial Moles
Possums
Rat Kangaroos
Sugar/Squirrel Gliders
Bats
Rats
Potoroos

Koala's might make it given their niche', but are very specialized.

Being closer to ectothermic relaives might ease their transition to lower-metabolism organisms (or improve their own natural low-metabolic rates).

My own thoughts, generalized, are as follows:

There would be several species of small Ankylosaur. These primitivre, heavily armored and extremely dumb animals would probably do well in this environment. They'd likey fill in the niche of modern-day wombats, grazing and holling up in burrows/dens during the colder months.

Hypsolophodontids would fill in most of the niches currently occupied by Kangaroos, Wallabies and other Macropods.

There would likely be a single large Carnosaur, probably around the same dimensions of the dwarf Allosaur species found in Australia's early cretaceous--5-6m long, 2.2m high and about half a ton in weight. Possibly it would be covered in small feathers, or not-depending if subspecies devlop for certain habitats (those rainforests can get fleece-wearing cold in the winter).

Onithomimids would likely fill in the niches of the ground-birds of Australia (Emu and Casoauri).

There would likely be two other carnivours -- an equivilent to the wolf and fox/Hyena/Tasmanian Tiger and Tasmanian Devil. I'd go with a dromeosaur and a troodontid.

Iguanadonts would likely fill in the large herbivor rolls, but throwing in the weight restrictions, they'd likely be 4-6m long, and up to 3 tons, with multiple species.

A Titanosaur might make an appearence, but would not get much bigger than an elephant (at least, at the shoulder), and be a giant Gigantotherm.

Another posibility would be to check out the Mongolian dinosaurs for comparison, given the similar environment (AFAIK). -- with Pachycephpolosaurs, Protoceratopsians, Dromeosuars, Hadrosaurs, Troodontids, Oviraptorids, Ornithomimids, Tyrannosaurids and Ankylosaurs to give a general of what could make it in such a desert back then (though, IIRC, it was a little less arid in the mongolian deposts of 80 million years ago).

And there is (scant) evidence of most of those families in Australia.

Darth Raptor · Post by **Darth Raptor** » 2006-03-17 03:58pm

Zero132132 wrote:If dinosaurs had survived in Australia, would they really have been so isolated that they wouldn't have affected the environment elsewhere?

Yes.

woveraptor wrote:Gregory S. Paul says in Predatory Dinosaurs of the World that stiff-bodied, bird-like dinosaurs fare poorly in the world of small terrestrian animals because they, unlike mammals, are not supple-bodied. One thing I've seen that seems to support this is the increasing number of mammals being found to play in important ecological role in the small omnivore or insectivore niche. Dinosaurs seem unable to fill this position. Because of this, I'm not sure what would occur in Australia, where many animals are modestly-sized. Mammals would still have a powerful hold there, and dinos would probably fill the niches of tasmanian devils, dingos and kangaroos.

Yeah, mammals would thrive, no doubts there. They simply wouldn't occupy the medium to large herbivore niches, or any significant predator niches.

Oh, you won't find any ornithomimids, dromaeosaurs or troodontids in Australia. I suppose ankylosaurs and titanosaurs are possible, but I would put my money on almost all significant herbivore niches being occupied by iguanodonts and hypsilophodonts.

Majin Gojira · Post by **Majin Gojira** » 2006-03-17 04:42pm

Actually, there is the Ornithomimid Timimus. And there is some dromeosaurid material:

Dromaeosaurid:

Teeth from the Southern Victoria sites (Otway and Strzelecki ranges), 106-115 MYA. Unlike the teeth of many northern hemisphere dromaeosaurs, which have denticles (serrations) on both edges of the tooth, the Victorian examples only have them on the inside (posterior) edge. This pattern is also seen in the second maxillary teeth of Sinornithosaurus millennii.

?Dromaeosaurid:

A partial humerus from Western Australia (Giralia ranges) dating to the Late Cretaceous. It is poorly preserved and there is some doubt as to its original classification. It could have come from a small theropod with large arms (like a dromaeosaur), or perhaps from a much larger theropod with reduced forelimbs. There has been some suggestion that the humerus could possibly be from a therizinosaur.

Troodontids is a streatch.