Re: EVOLUTION OF BIRD

["Ralph Miller III" <gbabcock@best.com>]

I've been reading Chatterjee's _The Rise of Birds: 225 Million Years of
Evolution_.  One thing that strikes me as odd is that, although this is
apparently Chatterjee's meticulously illustrated answer to the critics who
have been asking for a paper describing Chatterjee's interpretation of
_Protoavis texensis_, there are neither illustrations nor photographs
anywhere in the book to show the position of the _Protoavis_ bones in situ,
nor even any photographs of the bones themselves (which would help us to
appreciate the condition of the fossils), nor a thorough accounting of the
extent of skeletal elements recovered.  This would appear to be a serious
omission considering the reservations expressed by Chatterjee's peers who
have actually seen the material.  Ignoring this oversight, I found other
sections of the book informative and provocative.

I have a question.  How confident can we be of the assignment of
pre-Archaeopteryx tracks to Aves?  On pages 137-138, Chatterjee depicts and
describes tridactyl and tetradactyl prints which show a wide divarication
angle between digits II and IV, caudally directed halluces, and slim claws.
 Among these footprints are _Plesiornis_ from the Late Triassic Manassas
Formation of Virginia and _Trisauropodiscus_ from the Early Jurassic
Portland Formation of Massachusetts.  Can we tell from the tracks alone
that these were birds?  Can we formulate valid generalizations regarding
the range of divarication angles of the phalanges of small non-avian
coelurosaurs?

-- Ralph Miller III     gbabcock@best.com