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Re: Greg Paul is right (again); or "Archie's not a birdy"
Gregory S. Paul <GSP1954@aol.com> wrote:
> While I'm on this, it is a pecuilar feature of the main Xu et al cladogram
> that at the base the taxa are short tailed Early Cretaceous taxa, which
> implies that the Late Jurassic archaeopterygids reevolved long tails.
Or that short tails evolved more than once. This doesn't sound too
unreasonable, in light of the fact that short-tailed taxa such as
_Beipiaosaurus_ and _Nomingia_ arose independently in other
maniraptoran clades. Forelimb truncation is a recurring feature among
non-avian maniraptorans (_Caudipteryx_, _Mahakala_, _Balaur_, etc).
So why not caudal truncation?
> Me very,
> very doubtful about that, its a real stretch. This sort of thing is one
> reason I won't do cladograms since I would not be willing to publish what is
> probably an errant result like that. I mean really, I'd be embarrassed and
> would have to spend a good chunk of the paper ranting about how its probably
> not true. I'm not kidding. What would I do if a cladogram I ran came up
> with results that did just not appear to make sense as they fairly often do,
> publish it and call it a load of crap?
Doesn't make sense to whom?
> Best avoid such awkward situations.
> Anyhow, it is much more likely that deinonychosaurs were basal to the short
> tailed dinobirds, with LJ archaeopterygids being basal to later
> that were either better adapted for flight or secondarily flightless. Then
> came along the short tailed fliers which spun off short tailed nonfliers.
> Just makes more sense to me.
You believe a cladogram because it puts _Archaeopteryx_ in the
Deinonychosauria, and therefore "makes more sense" ... but otherwise
the method sucks? I don't think it's kosher to cherry-pick a
cladogram, but malign the method that generated it. Just sayin'.
> If so then the beginnings of dinoavian flight was
> pretty predaceous, and then went more herbivorous. Call me screwy for
> prefering phylogenetic-temporal logic and instinct over computer character
> crunching, but that's what got me to were I am today so I don't mind being
> crazy -
> like a fox.
To play Devil's advocate here... aren't you going down the same path
as the BANDits, in coming up with 'phylogenies' that fit pre-conceived
notions? I'll readily concede that, unlike the BANDits, your approach
has had some success - especially if the
_Archaepteryx_-is-a-deinonychosaur hypothesis gains traction with
future discoveries. But despite the intuitive attraction of the idea
that dromaeosaurids, troodontids and oviraptorosaurs were all
secondarily flightless, the osteological evidence (especially the
dearth of features required for sustained, flapping flight) points to
a more conservative hypothesis that powered flight is limited to
pygostylian birds (and so was absent from archaeopterygids,
jeholornithids, and maybe confuciusornithids as well).