Bzzzzzzzzzzz (was Re: Mongolian troodontids)

["Tim Williams" <twilliams_alpha@hotmail.com>]

> Free access to heaps of AMNH papers!
>
> http://diglib1.amnh.org/novitates/

Thanks David.  One paper in particular caught my attention:

Engel, M.S. (2003).  A new interpretation of the oldest fossil bee 
(Hymenoptera: Apidae).  Am. Mus. Novit. 3296: 1-11.

The 65 MYA eusocial stingless bee _Trigona prisca_ is put in its own genus 
_Cretotrigona_.  Its place in apid phylogeny indicates that bees diversified 
long before the end of the Cretaceous.

This got me thinking... a lot has been said lately about a "trees down" 
origin of flight, courtesy of the evidence for gliding and scansoriality in 
_Microraptor_.  But maybe avian flight did evolve from the "ground up", 
among theropods that leaped into the air against insects.  However, the 
target was not flying insects, but their combs and nests.  This removes the 
difficulty of explaining how small cursorial theropods could have 
outmaneuvered flying insects.  Combs and nests offered a stationary target - 
as did spiders' webs, or arthropods just sitting on leaves.

Again, I don't want to breathe life into the old "ground-up" vs "trees-down" 
debate.  I think the ancestors of birds divided their time between both 
ground and the trees, and both played a role in fostering the development of 
the wing.  Maybe "Proavis" was an opportunist, and leaped from either the 
ground or a tree-branch, depending upon what was more convenient.



Tim



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