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Re: Revising Hou et al, 96 (woo-o-o-o-o-o-o doggy!)



Mickey Mortimer (Mickey_Mortimer111@msn.com) wrote:

<Yes, you've kept the same theme.  However, you change the structures we
are speaking of in various exchanges, which gets VERY annoying.  This
sounds like nit-picking (and probably is), but debating is EXTREMELY
difficult when one party misquotes the other, claims to have not said what
they said previously and changes topics without warning or reason.>

  I went back and read my previous posts last night. Spent an hour and
half doing this to clear what I saw as the chain of conversation in each
topic. What I saw was quite different than what you did, as in my
continuity (notice qualification there) I was responding only to things
you said previously, and kept in mind their continuity. I noticed in
several instances that in a paragraph, I will include more than one topic,
but your response argues the use of just one. Subjects including
*Rahonavis* are dominant. If you want to talk about nitpickting, this
entire conversation has been about nitpicking. (But, to defend the
condition, despite the dislike of it, this is actually how you refine a
theory in practice through discussion; you need to defend it and the
things that produced that particular concept so that it comes into light.
It's called being thourough.) To this purpose, I will snip the parts about
what you think I was saying.

---

Here's the chain:

Mickey wrote:

<<That are all also found in Rahonavis, a probable avialan.>>

I wrote, with opening explanatory line (because I cut out the previous
writings, and thus needed to clear up what the first sentence was about --
as I typically do):

[on elongated rostral chevron processes], Mickey also wrote:

<Too a much smaller degree. But perhaps with the pedal morphology, this
is only a paravian/eumaniraptoran apomorphy, and non-illustrative to the
phylogeny of *Sinornithosaurus*. However, see below...>

  Only the first sentence was about what Mickey was talking about. This
was the only time I said anything about any part of *Rahonavis* that was
not it's sternum or foot. How this devolved into some contention that I
was supporting rostral processes as in dromaeosaurids, I don't know. Yes,
I wrote a line about *Rahonavis*' tail.

<Now, answer the question this whole exchange was about in the first
place- What pedal characters does Microraptor have (and Rahonavis lack)
that would support putting Microraptor in the Deinonychosauria?>

  The thing this whole conversation was about in the first place was
*Sinornithosaurus*. It devolved (fall away fromk its goal) as a result of
bringing up *Microraptor* and *Rahonavis* (first for sternal anatomy and
then for pedal anatomy). However, the elongate caudal laminae of
metatarsals II and IV that fold caudally and form what I am to understand
is the subarctometatarsalian condition, with minimal pinching, and
occlusion of the third metatarsal from caudal view, and a generally
shortened metatarsus relative to tibial length (something that all
dromaeosaurs have, for some reason -- I have not quantified it though, but
I regard it as unneccessary).

<Well, I suppose we can disregard Xu et al.'s (1999, 2000) phylogeny too,
it doesn't include Sinovenator either.  And of course we'll disregard Xu
et al.'s (2002) phylogeny too, it didn't include Yandangornis, Microraptor
or Sapeornis.  While we're at it, let's disregard all phylogenies as
outdated because not one published example includes all relevent taxa. 
Sorry Jaime, you won't disregard my phylogeny that easily.>

  Yes, I will. I can disregard any phylogeny on the basis of missing data
that is available. Xu did not have *Sinovenator* previous to 2001, and it
was not described until 2002, at which point it was included. In the
preceeding SVP oral presentation program, *Microvenator* was included and
it is my understanding that this refinement will be published in the
monograph. *Yandangornis* appears to be relevant only in your phylogeny,
but this is immaterial. If you find this problematic, give me your matrix
and _I_ will code *Yandangornis* for you. Same for *Sinovenator*.

  To reiterate, I would never defend a matrix' conclusions if it was not
concise. Notice I do not defend any previous phylogeny? *Sinovenator* is
the most recent taxon to be placed in a _published_, they-saw-the-specimen
phylogeny, and support for the placements it offers is strong. It looks
like it is a good deal better and more refined than previous phylogenies,
and remarkably inclusive of coelurosaurs than same. Until something better
and more conclusive comes along, the Xu et al. analysis is the best I've
seen. The absence of *Microvenator*, as was noted when it came out, is
troubling, but the paper was apparently in submission at the time, this
will have to wait until the next publication.

<Sure, Jaime.  Just claim characters that are homoplasious in your
phylogeny are "functional",>

  I never said functional characters _are_ homoplasious. They _can_ be. I
am wary of all functional characters as a result. They may or may not be
illustrative to phylogeny. I can cite beak shape, tooth morphology, jaw
articulation anatomy, supradentaries and suprarticulars, etc. Map a
character to a phylogeny, like medial orientation of the symphyseal
portion of the dentary, and it comes out as a clarifying synapomorphy of
some taxa, but is nonetheless homoplasious. Some troodontids have it,
caenagnathoids+*Caenagnathasia* have it, and therizinosauroids have it
(but not more basal taxa). Nothing else does. This produces excessive
homoplasy in a possibly phylogenetically informative character. Beak shape
and tooth morphology are directly related to diet, and I cannot see these
as phylogenetically informative in most cases. This may be hard to do, but
some things have to be lost to preserve the thrust of science.

<And therefore not phylogenetically informative.  You do realize the vast
majority of characters used in phylogenetic analyses are functional,
right?>

  A great majority of them may be. Refer to previous paragraph.

<Just what characters aren't functional?  Display devices.....perhaps the
rearranging of some skeletal elements while keeping a similar
structure....>

  This may be a hard fact to swallow, but a good deal of skeletal and
integumentary characters are functional and homoplastic in their varied
expression in unrelated groups. Robustness, sexual dimorphic features,
lachrymal ornamentation, size-correlated proportions, etc., are all
first-order functional in nature. Claw shape, tooth shape, etc., are
similar.

<Surely you've noticed evolutionary trends are never that smooth. 
Evolution is messy and rife with variation.  The maniraptorans we're
looking at are hardly acestors and descendants of each other, they are
separated by millions of years and thousands of miles.  Be realistic.>

  Gosh ... wasn't this my whole point? Order and pattern is human
conciousness trying to interpret what is, implicitly, a horribly chaotic,
interrelated web of life and relationship. Things don't actually fall in a
smooth set of patterns, and trying to say that phylogeny must conform and
that one phylogeny can be better than another requires understanding
_why_. This is why I view phylogeny as important, but it is the output of
a process that has many flaws, and I have been looking at theoretical
principles to weeding these out via several statistical and algorhithmic
methods. I can as easily make a phylogeny by hand, and map characters that
way....

<The problem with size-related characters is not their homoplasy, it's the
fact that when size changes in a lineage, they must also change.  Thus,
you get a group of correlated characters, which ARE bad, because they skew
analyses based on parsimony.  I actually think there's nothing wrong with
a single character in the form of "average size over X units", as changes
in size undoubtedly have a genetic (and therefore inheritable) basis.>

  Most sizes within one and within several populations tend to be
ecological. Big size in small animals is typically a result of an
ecological drive to outperform other animals. In response to environment,
large animals can become small. There are several races and species of
dwarf elephant and mammoth, but their phylogeny indicates that size
between them does not relate to phylogeny. Tyrannosaurs have no exclusive
relationship with allosauroids, despite being very large. And while this
size-difference may have a genetic effect, it is still typically not
phylogenetic in nature.

<Almost EVERY character is of potential phylogenetic utility.  Excluding
characters a priori based on assumed convergence is a horrible practice.>

  I do not exclude characters a priori. I consider all similarities
between two taxa, and list them. My list for both the
segnosaur+oviraptorosaur and the oviraptorosaur groups are in fact quite
extensive, accounting for nearly 50 characters between them. It is in
analysis that I find which are functional, size-related, etc. This is when
I begin removing them from the matrix. But I put them in first.

<You think we magically know enough now to say since Sinovenator lacks a
parasphenoid bulla, it can't be a bullatosaurian synapomorphy?  So
maniraptoran troodontids are the current consensus, several years ago
Bullatosauria was extremely popular.  We could find an even more basal
troodontid with a parasphenoid bulla, making Sinovenator's condition a
probable reversal.  All characters must be included so that all potential
relationships can be tested.  Or else you'll end up like Sereno, making
cladograms that just show what you think and never give alternate ideas a
chance.>

  I think you should know Sereno's method before attacking him. This
conversation has never been personal on my part, and I have tried to
maintain such a theme in all my posts. I have had quite civil
conversations with people I strongly disagreed with, and included
thoughtful courses of action for me to explore.
 
<Also, whether Sinovenator's parasphenoid rostrum is hollow is unknown. It
lacks an expanded parasphenoid rostrum, as does Sinornithosaurus.>

  It is suggested that *Sinornithosaurus*, according to Xu & Wu (2001),
has a hollow parasphenoid rostrum. This would suggest that the pneumatic
basicranium may be a tyrannoraptoran character that would not be
elucidative to relationship [it is present in *Tyrannosaurus*,
*Gallimimus*, *Velociraptor*, *Citipati*, and *Saurornithoides*;
*Sinovenator*, and even *Archaeopteryx* have pneumatic invagination of the
basicranium].

<Hmm.  What do we have here?>

  The same topic as before, apparently. My previous statement had nothing
to do with fibulae, but an earlier one from you introduced it as a
conversational piece. I simply chose to continue with my previous thesis.
I note, however, that you use the distal end of the fibula as a meter,
which you might as well use the calcaneal width : tibial width, as the
ratios will be very nearly the same. Reduction of the fibular shaft, which
is what counts, has nothing to do with the calcaneal width. Similarly,
figuring robustness is not a matter of figuring width, so I have no idea
why you chose to perform that little excercise. The maniraptoran fibula
typically is much more slender than non-maniraptoran fibulae, even in
*Compsognathus*, as a matter of both width and craniocaudal length. This
is presently a maniraptoran character. As I attempted to show in my last
post on this, this can also be more instrumentally and functionally shown
to be an absence of need to counter compressionary forces during walking,
and tends to correlate to larger astragali versus smaller calcanea, and
fusion of the tarsals to the shin.

<You saying that using fibular robustness is bad if it's related to
arborality because arboreal taxa have delicate limbs. And that
Compsognathus has robust fibulae despite it's size because its ancestors
were not arboreal.  So Jaime, just how were you "saying nothing about
fibulae" in relation to arboreal habits?>

  You first brought up fibulae, not me.

I wrote:

<<...but this may be related to other mechanical effects and may show that
they were not truly as cursorial as previously shown. They would permit
ease of twisting in the lower limb, and this is destructive to tibial
compressive forces during the walk-run phase.>>

<If a character doesn't fit with a percieved behavioral correlation, we
can always explain it away with "other mechanical effects" or claim the
taxon didn't actually exhibit that behavior. ;-)>

  You should have asked. Or I could have elaborated. Reverse my conditons
from last post on reduction of fibulae. You get a robust fibula in bigger
animals. *Saurophaganax* has a more robust fibula than does *Allosaurus*
(or *A. maximus* versus *A. fragilis*) and tyrannosaur fibulae increase in
diameter as they get larger versus length. Albertosaur fibulae (and tibia)
are much more slender and longer per width than are *Tyrannosaurus*;
however, comparatively ornithomimosaur fibular are also relatively
straight, and compare anatomically to tyrannosaur shins. The mechanical
effects of a more robust fibula would be the same for a robust tibia, in
countering compressionary forces, resisting torsion, etc. "Other
mechanical effects," in other words.

<Did you even look at the description while writing this?  Microraptor's
holotype only preserves the proximal part of metacarpal II and no part of
any phalanges of that digit.  Unless you mean the new specimens, but you
seem determined not to tell me if your data is based on these.>

  I looked at the fossil. Distal metacarpal II is present, as an
impression.

<* note below you suddenly start talking about the pedal phalanx, while
ignoring the reason you keep saying Microraptor lacks a character for
which the element needed is undescribed.>
 
<Don't tell me to ask questions if you're going to ignore them.  Let's
repeat it- Do you have an early copy of the new AMN description of
Microraptor?>

  If I did, you think I would tell you onlist? Or that I would tell you at
all? I consider priveledge of information important in publication, as you
may note from the last big conversation we had on this list ... as I
recall, Tracy was involved in it. Just wait for the thing, darnit.

<No, it would be pointless for my old partially inaccurate matrix.  I'm
coding it for my new matrix, but who knows when that will be done.>

  Then please, stop trying to compare your two phylogenies. Discuss the
whole friggin' comparison when you get it done. Then you can have a
foundation for arguing the placement of certain taxa and problems in
distribution of so-called avialaean synapomorphies.

  I think it's times to call this thread off and permit time to cool down.
I've come close to swearing onlist and I would very much prefer not to. We
can rejoin this particular thread when tempers permit. Mine anyway. Off to
other posts.

  Cheers,

=====
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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