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Re: Tinamous: living dinosaurs



Yes, of course, we might well expect a radiation of diverse brooding strategies 
among Dinosauria, as so many millions of years went by and so many specialized 
lineages diverged.

There may even be a sample bias, also, for those taxa that nested on the ground 
on floodplains. I w=myself wouldn't be at all surprised if we find one day an 
alvarezsaur female seated atop one or two very large eggs, for example.

But, nonetheless, we have several samples of non - avian maniraptoran nests and 
they are consistent in the features of large numbers of eggs in the clutches 
and males brooding them alone.

Also, I'm not clear from your e-mail if you are suggesting that Tinamous 
evolved paternal - only brooding independently of ratites (since tinamous are 
not large and flightless)?

Let me put it this way: if you HAD to reconstruct the brooding of a non - avian 
maniraptoran now, wouldn't it be safest to go with the paternal - only brooding 
model? Anything else would be pure speculation.

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? It certainly could have been independently derived, 
but that just requires more assumptions and thus is less parsimonious.

Cheers
-Jason

On Jun 24, 2011, at 11:35 AM, Ronald Orenstein wrote:

> I would be very nervous about doing this.  We have no idea if paternal care 
> is a 
> basal character or simply a common feature (symplesiomorph?) of ratites.  
> Ratites are still neornithine birds, and there is a lot of intervening 
> evolution 
> between them and maniraptorians.  I would be reluctant to assume that any 
> behavioural characteristic of ratites not associated with large size or 
> flightlessness is any more likely to be a basal feature than  the behavioural 
> characteristics of any other ground-living bird (such as a lyrebird, for 
> example!).
> 
> Ronald Orenstein
> 1825 Shady Creek Court
> Mississauga, ON L5L 3W2
> Canada
> ronorenstein.blogspot.com
> 
> 
> 
> ----- Original Message ----
> From: Jason Brougham <jaseb@amnh.org>
> To: dinosaur@usc.edu
> Sent: Fri, June 24, 2011 10:17:27 AM
> Subject: Tinamous: living dinosaurs
> 
> I put up a  new blog post about Tinamous, and how they are underexploited
> as models for extrapolations about the biology of extinct maniraptorans.
> Since their egg brooding behavior is comparable to Troodon and
> oviraptorids, can we infer that the behavior between the father and the
> chicks was the same also?
> 
> http://web.me.com/jasonbrougham/Site/Blog/Entries/2011/6/18_Tinamous__Living_dinosaurs.html
> 
> 
> 
> Jason Brougham
> Senior Principal Preparator
> Department of Exhibition
> American Museum of Natural History
> 81st Street at Central Park West
> 212 496 3544
> jaseb@amnh.org

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