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Re: Segnosaurs ejected from AVES
What gets me is why the name Maniraptora, which is diagnosed by that
semilunate carpal block, wasn't good enough for this group; it even
defined the function of the wrist or "wing" in any included animal, except
that for some reason segnosaurids reversed the contition --
*Beipiaosaurus* has a fully fledged dromaeosaur-like semilunate carpal
block, and indicates that the condition was _reversed_ in later forms.
Now, after decided that Gauthier's name wasn't good enough, Ken will move
Aves up to it, and known a taxon out just because it lacks a single
diagnostic feature, whether or not the other fifteen or so various
unambiguous and ambiguous features fit. Here we get an example of making
the tree fit the theory, will-he, nill-he to anything else that might make
that tree _wrong_. There are about 20 different features that unite
segnosaurs and oviraptorosaurs. Knocking them all off because one feature
has apparently decided evolution in that area ... I'm sorry ... it just
won't work. Absolutely nothing except personal opinion and "feel good"
attitudes permit this to actually take place in any phylogeny. At this
point, it ceases to be anything like science.
Anyone wants to use a graded feature to define a group? Go ahead: it's
not an apomorphy in the sense that it is a distinct feature; how long a
tibia is is the same thing. I could have easily use the feature tibia >
100mm to name some groups of birds, but size is no apomorphy, nor is
length. I had to quantify the feature in the sense of my coding to a
measure of degree of arc, not even how curved it was. It should be plain
that gradational qualities are so unreliable and plastic that they make it
impossible to sit there and use them apomorphically because then you only
use a gradation segment ... no constant at all. But please, use it if you
would. The bowed ulna, slc block, caudal count, and so forth weren't good
enough, some feathered animals must be birds, so let's move Aves (which is
obviously the bird group and nothing else could be) up to the first animal
with feathers, but because that feature won't work, let's pick something
that must be so easy that is must support the theory it was just put
This just insn't science.
Jaime A. Headden
Little steps are often the hardest to take. We are too used to making leaps
in the face of adversity, that a simple skip is so hard to do. We should all
learn to walk soft, walk small, see the world around us rather than zoom by it.
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