[In reply to a posted excerpt covering the _Scipionyx_ fossil and the
suggestion that dinosaurs were crocodilian in lung structure.]
The _Scipionyx_ analysis is rather controversial, especially because it
conflicts with a mountain of evidence for the bird/dinosaur link, but
also because the same group made a similar analysis of _Sinosauropteryx_
based on what was later determined to be a fracture in the rock slab and
preparation glue. Does suggest that a lot of ideology went into that and
this current analysis, and maybe all should wait until the dino-logists
have had a look at the "liver". I've been following the debate on the
"Dinosaur Mailing List", which has been a great insight into how
different scientists can be at each others' throats over "rock-hard
facts".
Personally I'm with the dinologists because more evidence keeps getting
dug up that supports their claims, and the scholarship of the
ornithologists who oppose them is not always up to date on the data.
However the ornithologists do have some valid points, and it seems more
likely that many of the very bird-like dinosaurs are in fact large
flightless birds - i.e. secondarily flightless. For example,
_Velociraptor_ and the various Dromaeosaurs ["sickle-claws"
collectively] are very similar in form to _Archaeopteryx_, but several
actually have skeletal features related to flight MORE advanced than
"Archie". It's unlikely that such large animals evolved advanced flight
characteristics at their current sizes, but very likely that they
evolved from smaller volant forms. The find in Madagascar of a fossil
flying, sickle-clawed bird _Rahonavis ostromi_ suggests this very
strongly.
More fossils, especially well preserved ones, are needed to tell us just
how bird-like some dinos were and how dino-like some birds were.
Adam
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