Re: Ruben Strikes Back

[NJPharris@aol.com]

In a message dated 9/24/99 12:43:06 PM Pacific Daylight Time, 
Dinogeorge@aol.com writes:

> Well, secondary flightlessness has occurred in dozens of modern avian 
>  lineages independently and convergently. 

Though most occurrences were under specialized conditions, esp. on islands or 
isolated continents.


>Why shouldn't this also be the case 
>  with theropods, particularly since those flying ancestral forms were not 
>  nearly as derived for flight as are modern birds?

Speaking of which, why wouldn't they have been "nearly as derived for flight 
as are the modern birds"?  This hypothesis requires tens of millions of years 
of essential stasis at a low level of flightworthiness, even though only a 
few million years had to pass to derive fliers of essentially modern flight 
competence from _Archaeopteryx_ or like forms.

And bats and pterosaurs appear to have gone from arboreal (?) forms to 
full-blown fliers so fast that we don't even have any fossils to record the 
change--at least, none widely recognized as such.

--Nick P.