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Re: Microraptor hanqingi, new species from China.



Anthony Docimo <keenir@hotmail.com> wrote:

>  Then what is a great analog for basal paravians?


There may not be a "great analog".  Not in the modern world, anyway.
Why is it so important to have a modern analog in the first place?


With birds we have a group that evolved from within a lineage of
erect, terrestrial obligate bipeds.  This might only have happened
once in the history of the Earth (dunno about pterosaurs).  It may not
be appropriate to use behaviors documented in modern birds (which
collectively represent a highly derived subset of Avialae) to try and
reconstruct incipient arboreal or flight behaviors in basal paravians
or basal avialans.  WAIR has been criticized for this reason.


This issue is not unique to avian evolution, BTW.  There is a
hypothetical scenario for the origin of flight in insects that uses
surface-skimming behavior in stoneflies (Plecoptera) as a model for
how pterygote insects evolved flight.  This scenario has been
criticized on several fronts, especially given that Plecoptera are
fairly derived within the Pterygota, and surface-skimming in modern
stoneflies is clearly derived from flapping flight.  Also, it is not
clear whether the first pterygotes were even aquatic; for example,
basal pterygotes such as the Palaeodictyoptera (which includes the
so-called 'six-winged' insects) were terrestrial as both nymphs and
adults.


To answer Jason's query, it is quite possible that small basal
paravians moved around in trees, without needing a long or reversed
hallux.  But this is not the same as saying that they were arboreal.
To approach this issue scientifically, I think we have to identify
morphological correlates of arboreality in fossil theropods, rather
than invoke behaviors in modern birds as "easy" for any small theropod
to do.






Cheers

Tim