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Re: Tinamous: living dinosaurs



I think you're probably right in some cases. For example, if we consider three 
groups of flightless diving birds, and they all breed with the same strategy, 
it might be shakier to infer that their flying ancestors all bred the same way 
also.

But this seems to be an opposite case. It seems that, between medium - sized 
flying birds like tinamous, and huge ground ones like ostriches, there is less 
in common ecologically than between the ostrich and Troodon. Also, any of these 
animals can flip back and forth freely between paternal only, maternal only, 
biparental, and megapode - like no care strategies. All would fit their 
ecology, don't you agree?

Therefore I think it is remarkable that all the most basal living birds, and 
all the non - avian maniraptorans we have samples of, seem to have the same 
brooding strategy, and that is paternal only.

On Jun 27, 2011, at 2:01 PM, Don Ohmes wrote:

> On 6/27/2011 12:40 PM, Jason Brougham wrote:
>> In other words, isn't it most parsimonious to assume that the brooding 
>> strategy held in common by Troodon, oviraptorids, (possibly Gobipteryx), 
>> tinamous and ratites is a synapomorphy, rather than a strategy that was 
>> independently converged upon four times?
> 
> Maybe. Do the tinamous and ratites have compelling reasons to behave in the 
> specified way?
> 
> If a paternal-only model conveys obvious advantage over other models within 
> the context of the common aspects of ratite/tinamou lifestyle, and those 
> common aspects are time-transcendent and applicable to 'Troodon, et al', then 
> I would suggest that that makes convergence more likely. If, OTOH, everyone 
> is scratching their heads wondering "Why the heck are these birds are doing 
> this?", then that makes convergence less likely...

Jason Brougham
Senior Principal Preparator
American Museum of Natural History
jaseb@amnh.org
(212) 496 3544