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Re: Definitions



  *Warning!* Only part of this post is to be taken
seriously. Further, it is not a rant against Archosaur
J. :) Or maybe I should just put up the director's
note at the beginning of _Dogma_.... Without the
platypuses.

Georgiodraco olshevskii wrote:

<Keeled breastbones may go back quite a way in
theropods. I recall Dan Chure displaying the keeled
breastbone of his formerly headless Dinosaur National 
Monument allosaurid at a fairly recent SVP annual
meeting.>

  Perhaps in reply to Archosaur J's post?

  Fused sternae and keels are not key to flight, at
least by an evolutionary perspective: there are birds
that fly which do not possess keels ... or have
horribly reduced ones, and those that don't that do.
:) Furthermore, keeled sterna are present in more than
dinosaurs, they're known in pterosaurs and some other
forms mentioned previously on this list (as part of a
project, I am looking at keels and sternal fusion, so
this is important stuff! :) ). The ankylosaurids had
fused sternae, and further structures similar to birds
which are intrinsic to bird flight _now_ are present
in a host of non-flying and even non-dinosaurian or
archosaurian taxa. Others have mentioned some of this
on the "Pygostyle" thread.

  *Archaeopteryx* was capable of attaining flight,
perhaps even powered flight. All but one of the eight
specimens known (sadly, one is missing) lack sternal
keels, and in the one (Aktein-Verein spec. = *A.
bavarica*) that possesses it, it is quite small.

  However, the term "carinate birds" or "carinates"
does not imply that only these birds possess keels. As
part of my ongoing campaign to uphold separate
concepts between vernacular and scientific usage, and
the past-used discussion of scientific names not being
taken literally as an absolute, I will now scream at
the next person who supposes that Carinatae become an
apomorphy-based clade by allusion (not fact) that is
defined on the sole basis of the carina (keelbone)!
AAAAAAAAAAAAAAAHHHHHHH! Let this be a warning to you
all!!!!!!!!!!!!!!!!!! :) ;)

  Calmly,

=====
Jaime "James" A. Headden

  Dinosaurs are horrible, terrible creatures! Even the
  fluffy ones, the snuggle-up-at-night-with ones. You think
  they're fun and sweet, but watch out for that stray tail
  spike! Down, gaston, down, boy! No, not on top of Momma!

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