So Antarctica was once a part of the big super continent that broke up into the continents we have today. And Antarctica must have had several millions of years of warmer climate, obviously not covered in ice. So are there unique branches of life that evolved and thrived on Antarctica and then died off when the continent froze over? Have scientists been able to even search for this stuff considering the continent is just about completely covered in ice? Could there be some fossils of undiscovered taxonomic branches waiting under the ice? What era would this have been?
Dunno if it qualifies as a unique branch of life, but this link describes fossils of two previously unknown dinosaur species found in Antarctica.
I remember years ago seeing an article in National Geographic that showed fossils of some dino-type critter that was only found in Antarctica and India. The fact that the same beastie was found in such different regions was one of the bits of proof for the theory of continental drift.
Australia’s largest Antarctic fossil collection at Monash
I looked around the Monash U website, but did not find a geology museum museum page.
Antarctica is unlikely to have had much in the line of endemic higher taxa, since it was pretty much at the heart of Gondwanaland, and the overwhelming majority of orders, families, etc., were in place by the time it became an island continent. (It’s been icecovered for about 15 million years, though no doubt it was not much of a tropical vacation paradise beforehand – Tierra del Fuego, Kerguelen Island, South Georgia, etc., are not noted for their pleasant climate, which would parallel what it would have had before the icecap formed.
However, there are a lot of potential fossils under the ice – just from what is known from outcrops rising above the ice, the Glossopteris flora, Lystrosaurus (a rhynchosaur), and a few other of the key markers of Gondwanaland were discovered there. In fact, it was those finds that were essentially the turning point in the acceptance of continental drift among orthodox geologists.
What Polycarp said. A lot of South African Karroo fossils - the Glossopteris plants, the Synapsids (mammal-like reptiles),etc are also known from Antarctic finds.
One quibble, though, Poly - Lystrosaurus is a synapsid not a rynchosaur. Seen a few of the buggers locally. Once, in situ. Cute, though, like a Sabre-toothed Staffordshire Terrier in the latest reconstructions.
Also, the continent is not completely covered in ice. Parts of it (the “dry valleys”, IIRC) are relatively snow-free and scoured clean by high winds. Plus there are fossiliferous bits that poke out of the ice as mountains.
Like that found by the Pabodie expedition of '30-'31.
Does that mean there could be whole animals frozen deep in the ice from back then, in the same way mammoths have been found deep frozen in Siberia?
Well, the ice isn’t stable for that long. If flows slowly from the center of the continent out to the oceans, and there are periodic alternating warm and cold spells that will melt and refreeze the ice. And there would have to be creatures living on the ice in order for them to get frozen in the ice. Given that animals need food to live, there aren’t any animals that live on continental glaciers. The mammoths that are found frozen weren’t wandering over glaciers.
Anyway, there’s a big difference between being frozen for a few thousand years and being frozen for a few million years.
I had no idea really. I figured that the continent was formed so long ago that it would have had a much less diverse and developed set of organisms. There were dinosaurs on what is now Antarctica at one time? Fascinating. Were there also mammals there? Can anyone suggest a book on this subject? (One that a layman could enjoy).
Mr Dibble is of course correct – Lystrosaurus was a cynodont synapsid (“mammal-like reptile”), not a rhynchosaur. The finds at Coalsack Bluff in the Transantarctic Mountains, however, included a number of Triassic species including a rhynchosaur, which like Lystrosaurus has “sabre teeth” – in this case, however, formed of the frontal bone of the upper jaw, not teeth. These are of Early Triassic age – somewhat less than 250 million years back.
In reference to the question about mammals, I found an interesting bit of information that said that marsupials, edentates, and notoungulates had been found on the Antarctic Peninsula dating about 40 million years back. The marsupials were members of the extinct family Polydolopidae, which is typically South American rather than Australian, and the edentates and notoungulates are of course typical elements of Tertiary South American faunas.
The comment was that this find supports a theory that marsupials evolved in North America, spread into South America and radiated there, and then made their way to Australia across Antarctica before the ice cover formed. (The three continents were touching as close as 50 million years back.)
Right. Frozen animals are generally found in permafrost, not in glacial ice.
Looking up something totally unrelated to this topic on marsupials and following up a hyperlink, I found the following bit of interesting comment on this topic in Wikipedia:
The paper quoted is M. A. Reguero, A. M. Sergio and S. N. Santillana. (2002) “Antarctic Peninsula and South America (Patagonia) Paleogene terrestrial faunas and environments: biogeographic relationships”. Palaeogeography-Palaeoclimatology-Palaeoecology, 179, pages 189–210.