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Re: BCF AND PDW
<<Big theropods six feet long or bigger simply ran around flapping
their arms, and suddenly, like Peter Pan, they became small and could
fly. This is the miracle.>>
Tom Hopp (to whom I owe a great appology) wrote:
<...you imply that no theropods existed which were smaller than six
feet. Somebody once said that, due to the patchy nature of the fossil
record, it is virtually impossible to prove that something DIDN'T
EXIST. Doesn't your statement assume the non-existence of tiny
theropods in the Triassic/Jurassic that could have evolved into birds?>
To reiterate, *Eoraptor* and *Pisanosaurus* are contiguous taxa
(they lived at the same time) and are very close osteologically. One
is three feet long, the other three to four feet (I think) and the
closest known outgroup to dinosaurs, *Marasuchus*, was around two feet
long. The evolutionary gap between the lagosuchid dinosauriforms and
true dinosaurs (i.e. *Eoraptor*) is not large, but it gives some room,
about a few tens of millions of years, to evolve an arboreal, possibly
feathered form that developed into later coelurosaurian "dino-birds".
I would choose compsognathids (early age and "downy fluff" and
ornitholestids as jump-points to see how many steps it would take to
get from *Lagosuchus* to _________ (fill in blank).
Who's to say the arboreal or cursorial ancestor of avian or
non-avian theropods wasn't small? There's physiological room, and
Archie was only around two feet, and even squirrels are relatively
large (in fact, and a few may disagree, the larger sugar gliders are
more than two feet in length).
Of course, I'm busy with ornithomimids right now, so someone else
can do this analysis (if viable).
Jaime A. Headden
Qilong, the website, at:
All comments and criticisms are welcome!
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