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Re: Dinosaur Dreaming report 2003



Tim Williams wrote:
> 
> > > or surely it's possible that Teinolophos represents a dead-end
> > > branch of monotremes that retained primitive charactersitics
> > > long after other monotreme species
> > > had already given rise to the placental/marsupial line?
> 
> This would make the Monotremata paraphyletic, wouldn't it?

I was thinking something like this:


|Primitive Monotremes
|
|-----|Modern Monotreme line
|     |(dentary-only mandibles)
|     |
|     |-----|Marsupials/
X     |     |Placentals
      |     |
      |     |
      |     |
   (the present)

Where the X represents a primitive monotreme stock that survived in
Australia (but not to the present). Australia in the Mesozoic seemed to
have had lots of relic populations of animals extinct in other parts of
the world. 

Teinolophos is known as a micro-monotreme, given its tiny size. I know
of no other monotreme species that were this small as adults (in fact,
some of them were the largest mammals around in the Mesozoic).

-- 
________________________________________________________________

Dann Pigdon                   Australian Dinosaurs:
GIS / Archaeologist         http://www.geocities.com/dannsdinosaurs
Melbourne, Australia        http://www.alphalink.com.au/~dannj/
________________________________________________________________