Re: Gansus Bird-Dino Connection - Penn Press Release

[Michael Habib <mhabib5@jhmi.edu>]

> HI:
>  Then why do most Archaeopteryx reconstructions show it in trees?
>
> --

There are quite a number of reasons, many of which are of dubious logic.

One reason was that Archaeopteryx appeared to have a long reversed 
hallux with a highly curved claw, initially.  However, the most recent 
specimen demonstrated that the Archaeopteryx lacked a reversed hallux.

Additionally, arboreal gliding hypotheses for Archaeopteryx require an 
elevated launch point.  There are a couple of problems with this model, 
one of them being that the arguments tend to be circular.

However, arboreality and perching may not always correlate 1:1.  
Archaeopteryx, and several other Cretaceous birds (as well as 
Microraptor and kin) may have climbed quadrapedally, without actually 
perching.  Many modern birds that retreat to trees cannot really 
'perch' in the technical sense.  However, such a model is very 
speculative at present.

Cheers,

--Mike Habib

On Friday, June 16, 2006, at 04:47 PM, Ian Paulsen wrote: