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Re: Vegavis gen. nov. - new anseriform in today's Nature

Grasses in the Miocene..._Bullockornis_ in the Miocene.

Well... or Oligocene.

Re: "ordinary tropical rainforest".  This quote is from _Magnifiscent
Mihirungs_, by PF Murray and P Vickers-Rich, (2004) talking about popular
paleontological misconceptions: The vast majority of Australia's
vertebrate fauna evolved in, and were adaptive responses to, scleromorphic
woodlands that grew in any precipitation regime...it is about time we
retired this old rainforest flag." (don't have page number--quate is under
fig. 215).

Then what is Riversleigh???

Several factors relate to why Australia.  Any continental ground-nesting
bird has to either hide or defend.  If it hides it must have an effective
concealing medium (e.g., grass for ostriches).

Why do you think a rainforest is less effective?

Murray and Vickers-Rich note that egg shells have not been found at most
sites where predators are abundant.

AFAIK dromornithid eggshells are only known from *Genyornis*.

In either case, concealment may not have been
primary if predator density/potency was low enough.

Quite impressive thylacinid species coexisted with *Bullockornis*.