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Re: Island-dwelling dinosaurs (was Re: Gargantuavis neck vertebra)



Forgive a non-biologist's input, but Australia has always had bats (both 
Microchiroptera and Macrochiroptera, c15Mya) for a very long time, and also I 
think native rats (c5Mya; I saw one last year outside my back door - about the 
size of an otter with a 12" tail; beautiful looking thing. They're mostly water 
rats, not domestic).

Also seals, dugongs, and of course cetaceans.

On 20/06/2012, at 2:34 PM, Anthony Docimo wrote:

> 
> 
>> Dr Ronald Orenstein <ron.orenstein@rogers.com> wrote:
>> 
>>> I was under the impression that the placentals-beat-marsupials argument had 
>>> been pretty well rejected, with evidence that the reverse may
>>> have happened on Australia.
>> 
>> 
>> As far as Australia is concerned, this hinges on the identity of a
>> single molar, named _Tingamarra porterorum_, from the Eocene of
>> Australia. The tooth has been regarded as coming from a "condylarth",
>> and therefore a non-volant eutherian.
> 
> 
> 
> At some point, I think I had heard that Australia has been a long-time host 
> of...I want to say Rodents, but I'm not sure that's the right clade.
> 
> 
> 
> Basically, I thought *Tingmarra* wasn't the only placental  (or if its not a 
> placental, that there were still placentals on the landmass)
> 
> 
> 
> 
> 
>> If true, it indicates that
>> placentals were once established in Australia, but were beaten out by
>> marsupials. However, not everyone is convinced that _Tingamarra_ is a
>> placental. One suggestion is that the tooth comes from an
>> ameridelphian marsupial (also known from the Tingamarra fauna). As
>> you might appreciate, this is a somewhat hotly contested topic. ;-)
>> 
> 
>                                         

-- 
John Wilkins PhD
john.s.wilkins@gmail.com
Administrative assistant to Dr Neil Thomason, PI for IARPA Grant