"Pinnants" (was Re: BIRDY _ARCHAEOPTERYX_)

["Jerry D. Harris" <102354.2222@compuserve.com>]

Message text written by INTERNET:jjackson@interalpha.co.uk

>And good luck to them. The mani's I claim to be absent from the K (except
olshevskyans v. close to Archae) are the "maniraptora", which is
oviraptors,
'dromeosaurs' and birds.  I was not referring to "maniraptoriforms" because
that would include _Coelurus_, _Compsognathus_, _Sinosauropteryx_ and
_Ornitholestes_, which I don't want as Archae descendants.  However it also
contains the arctometatarsalia: ie the tyrannosaur and
bullatosaur(troodonts/ornithomimids) groups, which I do want.  I did start
by referring to the group as the Arctos/mani group, which would have been a
tautology had I meant maniraptoriforms which of course subsumes arctos.<

        Um...OK.  I'm not following something here (am I alone in this?) 
Firstly, as I recall, _Compsognathus_ as a compsognathid (and
_Sinosauropteryx_, if it is indeed a compsognthid) are considered basal
members of the Tetanurae (thus well below the maniraptoriform node), not
the Maniraptoriformes (or the Maniraptora).  As far as I know, few people
have outrightly stated that these two were descendants of _Archaeopteryx_. 
Second (and I'm sure Tom will correct me here if I'm wrong!), but the
Arctometatarsalia, as originally defined by Tom, has fallen apart, since
the arctometatarsalian condition in alvarezsaurids seems to have arisen
independently from any other group (what with alvarezsaurids being nested
with the Avialae, not closer to troodontids and tyrannosaurids).  I'm
unclear on whether the Arctometatarsalia still stands, but without the
alvarezsaurids, or if it's been dumped altogether (which wouldn't make much
sense to me, anyway...)

        Third, and more importantly, I'm rather unclear on (and,
admittedly, taken aback by) your phraseology above, about what you do and
don't want for this or that.  Perhaps I'm not reading this correctly (and
if not, please forgeive me and please also explain what I'm missing!), but
this brings to mind a political cartoon I saw a while back:  on the left
half (titled "The Scientific Method") is a university professor talking to
a student, saying "Here are the facts; what conclusions can we draw from
them?"  On the right half (entitled "The Creationist Method") is a
minister, proffing a bible, talking to a young person, saying "Here's the
conclusion; what facts can we find to support it?"  It _sounds_ as if
you've got a predetermined conclusion (that birds are not theropods) and
are dismissing evidence to the contrary simply because it doesn't uphold
your conclusion.  On the other hand (and yes, perhaps I'm beginning from my
own set of biases), the evidence for a closer relationship of
_Archaeopteryx_ and all other birds to theropods than to anything else has
been supported in multiple analyses, and the eminently testable data for
this has been put forth in numerous papers (and has yet, to my knowledge,
been superceded by an equally rigorous analysis with a more compelling data
set.

>>Of course, I don't actually agree with groupings which put troodonts
closer
to compsognathids for example than to birds...I shall refer
to all members of arctometatarsalia and maniraptora (in TMKeeseys
structure)
as "Pinnants".<<

        For the sake of this discussion, fine...but I must second Tom's
insistence here that new taxon names _not_ be bandied about in this forum
or anywhere else until defined and diagnosed in a scientific forum (journal
of some sort).

>>Enants
might either subsume the arctos or siblate them.  If the arctos did split
off before the enants, they wouldn't have had much time to do it, but they
may have done, because the whole lot of them would have been going faster
than Dave Martill's landrover in the first 10mys after Archae.<<

        Again, some confusion on my part.  One of the defining features of
enantiornithine birds is that the tarsometatarsus is completely fused at
the proximal end -- there is no reduction of the proximal end of MT III. 
Are you proposing that the arctometarsalian condition evolved by the
_un_fusing of the proximal tarsometatarsus, and then the reduction of the
proximal MT III?



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                     Jerry D. Harris
                 Fossil Preparation Lab
          New Mexico Museum of Natural History
                   1801 Mountain Rd NW
               Albuquerque  NM  87104-1375
                 Phone:  (505) 899-2809
                  Fax: ; (505) 841-2866
               102354.2222@compuserve.com