Dinosaurs survived in Antarctica? (Was: Re: "Dinosaurs Died Within Hours After Asteroid Hit Earth...")

[Michael Kaib <michael@kaib.org>]

> My question on birds originating in Antartica or on the southern 
continent
> is were not other dinosaurs also in that place at the time.    If as the
> genetic studies suggest the major categories of birds diverged during the
> Cretaceous, then atleast four to six groups of birds survived the 
exinction.
> How come they were the only dinosaurs?
>
> Yours,
> Dora Smith
> Austin, Texas
> villandra@austin.rr.com

Interesting question! There is no doubt that dinosaurs without flying 
capability inhabited Antarctica up to the K-T border. Although the 
fossil findings situation from Antarctica is quite poor, no reason is 
known for their extinction before the K-T border, since the Antarctic 
climate has been quite moderate in these times. It is an interesting 
hypothesis, that they could have survived the K-T border in Antarctica 
for possibly many million years. Due to the sparse known fossil record 
up to now I wouldn't know how to disprove this without more intensive 
local research. Of course surviving dinosaurs had become extinct by 
Antarctic climate cooling down, latest by the total glaciation in 
Oligocene - an often undervalued mass extinct where all Antarctic 
species lacking good swimming or flying capabilities became extinct - 
maybe including real non-bird dinosaurs.

At the K-T border the Antarctic climate was doubtless the globally most 
extreme. Hence the special Antarctic climatic conditions might have 
given Antarctic habitants a higher probability to survive the mass 
extinct. E.g. darkness lasting several years as recently postulated 
would not be very unusual for an Antarctic population. The Antarctic 
survival hypothesis could be a challenging motivation for further 
Antarctic research.

However, for birds a very important reason for their K-T border survival 
until today could be their capability to fly long distances. They were 
easily able to escape even rapid climatic changes by moving to habitable 
zones in far regions, even on other continents. This was rarely possible 
for land animals without flying or large distance swimming capability, 
since at this time the land consisted of 7 isolated continents and many 
large islands without land bridges. For long-distance swimmers like some 
crocodiles, swimming could have been a similar successful survival 
strategy in this global crisis. But it seems that crocs had a better 
strategy, because they were nearly untouched by the event. For some 
small mammals and lizards alternative survival strategies were more or 
less successful, as discussed above. This Antarctic survival hypothesis 
still leaves some open issues: Why became pterosaurs and plesiosaurs 
extinct? May be there is a different answer for them.

On the other hand, a global fire as postulated by Robertson sounds 
curious for me. I've read about recent research restricting the fire 
zones to less than 1000 km. And if there were a global fire why not in 
Antarctica? For me the reason for the extinction should to be a period 
of more complex rapid climatic changes. However, the latter survival 
strategies might have been important. I still search for a simple 
hypothesis explaining
-    extinct of (non-flying) dinosaurs, plesiosaurs and pterosaurs
-    reduction of mammals, birds and lizards to few small species
-    leaving crocodiles nearly untouched
at the K-T border. What happened to the other sea fauna, insects or flora?

Yours,
Michael Kaib
Munich, Bavaria
michael@kaib.org