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Re: "Feathery fossil shows birds aren't dinosaurs"



Dinogeorge wrote...

>Sorry, you are dead wrong here. If birds >descended< from dinosaurs like
>Deinonychus, Velociraptor, and so on, then we should be finding such
>dinosaurs in the Jurassic >before< Archaeopteryx as well as after
>Archaeopteryx. But we don't. They only occur >after< Archaeopteryx.

    Here, you are doing it again.  You just said this sort of assumption was
"hogwash".  A missing fossil record doesn't prove that something wasn't
there.  At least you don't have to extend the currently blank fossil record
for bird-like dromeosaurs as far to put them immediately before
Archaeopteryx as you do for Triassic archosaurs.  Why is your stretch more
reasonable?

>All the
>bigger theropods of the Jurassic are much more primitive theropods,
>descendants of the much more primitive dinobirds of the Triassic and early
>Jurassic.

    Whatever came right before Archaeopteryx must have looked something like
it, and Archaeopteryx looks an awful lot like a dromeosaur.  Even if you
want to argue that most of the really bird-like features shared by
Archaeopteryx and Cretaceous dromeosaurs appeared in Archeopteryx first, its
immediate ancestor couldn't have looked too radically different.  Something
bird-like, and more bird-like then most Jurassic theropods, was around right
before Archaeopteryx.  You say dino-bird, others say Jurassic dromeosaur.
    Even if you are right about dromeosaurs being descended from
Archaeopteryx, Archaeopteryx still looks a lot more like Jurassic theropods
then it does like Longisquama.  At least we have fossil evidence that there
were theropods of some kind around in the Jurassic.  If you must have an
arboreal origin of flight why don't you just take a cursorial early-middle
Jurassic theropod and stick it into a tree, rather then inventing a
completely hypothetical lineage of dino-birds?  If there was no Jurassic or
Triassic fossil record of theropods at all, I could understand the
neccesity, but not when there is.  You don't have to change a known Jurassic
theropod as much to make it look like Archaeopteryx as you do for ANY
non-dinosaurian Triassic archosaur.  Again, why is your stretch more
reasonable?

>The big problem is that dinobirds were small animals not easily recovered
as
>fossils, whereas their larger descendants made for large fossils. This
>collection bias has strongly skewed the understanding of how theropods and
>birds are related, as your post demonstrates.


    Your statement could be applied equally to Jurassic dromeosaurs.  You
can't just apply this argument to one group, then say the exact opposite for
the other side.

LN Jeff

You have to study a great deal to know a little.
-Baron de Montesquieu

They may forget what you said, but they will never forget the way you made
them feel.
-Carl W. Buehner
********************
Jeffrey W. Martz
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