[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: dino extinction



Nick Longrich wrote:

>     I sit and wonder how on earth the dinosaurs could have gone
> extinct, after all that success. And then when I'm done with that, I
> wonder how on earth mammals could have gone extinct. They did in one place
> in the world, New Zealand.

According to Archibald's data on K/T extinctions in Montana (and I can 
thank John Bois' previous posting for this info), less than 10% 
of marsupial species survived the end of the Cretaceous in North 
America.  Placentals, by comparison, apparently survived unscathed.

Mesozoic mammalian faunas of Australasia are very poorly known; to my 
knowledge, only two species, both monotremes (E. Cret., sthn 
Australia), have been found in the region.  Nevertheless, it is 
possible that only monotremes and marsupials existed in the Antipodes 
during the Cretaceous.  In other words, placentals may never have 
arrived there in the Mesozoic.  So, if Archibald's data holds true 
for New Zealand, then the event that nearly wiped out the marsupials 
of North America could easily have wiped out ALL of NZ's mammals.

> I don't think that they were there in the past 65 million years and
> went extinct. And I don't buy that they weren't there initially.

Almost certainly there were mammals there.  Just the wrong types of 
mammals.

>  Which makes me think that it's likely that whatever did
> in the dinosaurs did in New Zealand mammals as well.
     
Agreed.  And the enantiornithines, and the pterosaurs, ...etc. etc. 
 
Tim Williams