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R: polyphyletic Alvarezsauria assemblage



From: Ken Kinman


> Mickey, Jaime, and others,
>       I've been looking at the characters that supposedly unite
> Alvarezsauria, and all I can see is a bunch of homoplasic >"noise".




>The
> first two (small cervical epipophyses and neural spines) seem to be very
> subject to convergence and found in other groups.  Procoelous caudals and
> sacrals pop up here and there in all kinds of archosauromorphs (incl. the
> bird Patagopteryx), and they grade into slightly
procoelous-to-amphiplatyan
> forms in a variety of neotheropods.  I find nothing convincing in this
list
> of so-called synapomorphies.

****other nine were listed....arguing against the validity four is not
exactly like showing they're ALL  unappliable...but as usual you've got your
and ear telling you of "homoplasic noise".....mah...


 > The similarities appear to be pretty
> superficial and homoplasic.

****"apper" ... "are likely to be" ..."seem to me"..."make me think"...
what are we talking about???



>      My conclusion is that Alvarezsaurus is fairly closely related >to
> segnosaurians, and it would not surprise me if they form a clade.

****OBVIOUS!......being possibly unrelated to one clade makes a taxon
automatically close to something else??

>On the
> other hand, the differences between Alvarezsaurus and Mononykiformes are
> considerable, and I can certainly discuss those when I have more time.  I
> never did think they were related (as I have expressed on this list from
> time to time), and now I am even more convinced such an assemblage is
> polyphyletic.

***Why are you NOW even more _convinced_ of this? has any new evidence come
out?  or is it just that you need that to be so?

>      Order Mononykiformes, is much closer to birds, as is Family
Avimimidae.
>   It would not even surprise me if mononykiforms and Avimimus form a
> holophyletic group.  They are certainly far more alike than either is to
> Alvarezsaurus.  It is really too bad Alvarezsauria is anchored on
> Mononychus, because I think we have another Ornithosuchia problem here.
> Alvarezsaurus may be several outgroups away from Alvarezsauria (if you do
> anchor it on Mononykus).  This is a mess.  Sorry, but EVERYONE doesn't not
> think this is a holophyletic group, and what surprises me is that it has
> gone almost unchallenged after so many different cladistic analyses.

***does it really surprise you??  so many different analyses  coming to the
same conclusion and you're surprised of the fact that nobody has challenged
this?  well, perhaps they have just  looked at how things really are, have
put their codings into their matrices , run their analyses  and got the same
results....should have they argued against those results only because they
didn't like them?  .... hope I've missed your point here

Filippo


>                          Ken
>