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Re: Island mammals



I'm a little behind in my Email so I apologise if this is really out of order.

>>>The only island ecosystem I can think of, in which the top >predator prior
>>to human intervention is a non-avian tetrapod >that seems substantially to
>>have evolved in place (rather than >being a small modification of something
>>that came with the >island, as in Tasmania or Madagascar), is Komodo...

I haven't followed this thread too closely, but how did Tasmania sneak in?
Firstly, it has only been something like the last 20,000 years that
Tasmanian has been an island. Prior to this it was connected to mainland
Australia due to lowered sea levels. And 20,000 years is hardly enough time
to evolve anythiong special. Secondly, exactly what what non-avian tetrapod
evolved into the to predator role in Tasmania?

>New Caledonia had until very recently a terrestrial Crocodile.

This is Mekosuchus inexpectatus, probably went extinct at the end of the
Pleistocene although there is some claims of younger specimens based on
dodgey stratigraphy. Top predator? Maybe, but remember that Mekosuchus was
only a metre or so long, not particularly big.

>In New
>Guinea today the largest predators are crocodiles and monitor lizards; even
>in Australia you might argue for the Saltwater croc, the Perentie and one
>of the larger pythons as up there with the thylacine.

Pre-people (around 60,000 years ago) we had much bigger reptiles than
mammalian carnivores, as has been discussed on this list previously.

And the news over here, if it hasn't filtered through yet; last years
claims of Aboriginal sites in Australia dating to between 116,000 and
176,000 years old have been bought into question this week. Revision of the
data by other workers has given dates of around 20,000 years, well within
the normally accepted range of ages normally accepted for Aboriginal
occupation of Australia.

Cheers, Paul


Dr Paul M.A. Willis
Consulting Vertebrate Palaeontologist
Quinkana Pty Ltd
pwillis@ozemail.com.au