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



Jaime Headden wrote-

> <You keep changing what you say you're writing about.>
>
>   I have maintained one theorem during this entire discussion: ambivalence
> of character support for *Sinornithosaurus* as an avialaean. I will
> continue with a refutation of your features supporting *Sinornithosaurus*
> as avialaean as refutation of your interpretation of its anatomy. This is
> below.

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 will use the
example below.

> <1. I listed the elongate prezygopophyses and chevrons of Sinornithosaurus
> as one of the characters Xu et al. (1999) used to assign it to the
> Deinonychosauria, but said this was also found in Microraptor, "which is
> even more bird-like (but still thought to be a deinonychosaur by many)."
> 2.  You replied by saying yes Microraptor is thought by many to be a
> deinonychosaur, and "for many other reasons, including the pes
> construction (an apparent troodontid + dromaeosaurid synapomorphy, along
> with pedal digit II features)."
> 3. I replied that these "deinonychosaurian" pedal features are "also found
> in Rahonavis, a probable avialan."
> 4.  Now, you become confused.  You cite my quote above as being in regards
> to "elongated rostral chevron processes", which it wasn't.>
>
>   Uhm, err, no I didn't. My statement above (now deleted) was in direct
> reference to "pedal characters", nothing more. I wrote very little (if
> any, as I recall) about the tail in any of these animal.
> Thanks for refreshing my memory ... and sincerely, appologies if I
> confused you, but I was staying very true to each comment's origin, not to
> refer to different subjects.

You didn't, did you?  Jaime, look here-
http://www.cmnh.org/fun/dinosaur-archive/2002Apr/msg00539.html
Go down to my quote "That are all also found in Rahonavis, a probable
avialan."  Notice that immediately above my quote, you state-
"[on elongated rostral chevron processes], Mickey also wrote:"
As can be clearly seen, you DID cite my quote as being in regards to caudal
characters, not pedal ones.

> <After this you reply that they are present in Rahonavis "Too a much
> smaller degree.">
>
>   I never said anything about *Rahonavis'* tail ... are you sure you're
> not confusing me with David? What I have to say about *Rahonavis* will
> come later....

Again, on http://www.cmnh.org/fun/dinosaur-archive/2002Apr/msg00539.html
where you incorrectly cited my pedal quote as pertaining to "elongated
rostral chevron processes", you follow with saying that Rahonavis has
whatever character you think we're discussing "to a much smaller degree".  I
assumed you meant a caudal character, as you misquoted me as discussing a
caudal character.
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?

> <A. Elongate caudal prezygopophyses and chevrons are a possible
> deinonychosaur character of Sinornithosaurus, assuming Microraptor is also
> a deinonychosaur.  However, if (as in my phylogeny) microraptor is an
> avialan, they tell us little about Sinornithosaurus.>
>
>   And because your phylogeny does not include *Sinovenator*, I will for
> the moment disregard it as ... outdated.

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.

> <B. Rahonavis has a more strongly developed sickle claw than Microraptor,
> so sickle claw characters are very poor evidence for deinonychosaurian
> affinities in the latter taxon or Sinornithosaurus.>
>
>   At some point in the past, I suggested that claw morphology in the
> sickle-clawed dinosaurs were possibly functional to effect, and would play
> little, if any, phylogenetic part.

Sure, Jaime.  Just claim characters that are homoplasious in your phylogeny
are "functional", and therefore not phylogenetically informative.  You do
realize the vast majority of characters used in phylogenetic analyses are
functional, right?  Just what characters aren't functional?  Display
devices.....perhaps the rearranging of some skeletal elements while keeping
a similar structure.... .  I'm sorry Jaime, but unless you want to claim
that current morphological analyses using parsimony are useless because they
almost exclusively use "functional characters", this arguement won't hold.

>   And back to my refutation, which was ignored, I guess, that
> *Archaeopteryx* does not have the caudal metatarsal phalanges, in any
> metatarsus I've seen (I have photos of each specimen) that _would_
> indicate that, except to compare the caudal convexity of the outer and
> inner shafts. This is seen in many bird metatarsi, including *Avisaurus*
> and many other enantiornithines, much more derived than seen in
> *Archaeopteryx*, and are probably not flanges but simple ridges on the
> exterior corners of each shaft.

I suppose this character will remain ambiguous then.  Paul thinks it does,
you think it doesn't.

>   Yes, I do expect a nice smooth curve. Otherwise the character is too
> "lumpy" and possesses too many anomolies for effective use. Were it that
> life were binary, but even a gradational model is not apparent, as each
> taxon appears to affect the position of the nares or premaxillary
> subnarial depth (which is relative to tooth-root length) differently.
> Providing a commonality to each level higher into birds, and maybe I'll
> agree with you, but I see this as functional variation. As I said,
> ornithomimids have modified snouts, each dromaeosaur varies on its own, as
> do troodontids, and this cannot be used as you do. I think the wheat was
> lost in the chaff....

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.

> <Even if a character is definitely very homoplasious, it should not be
> removed from a matrix.  There still may be subsets of the apomorphic taxa
> that truly share the character, like ornithomimosaurs + alvarezsaurids for
> instance.>
>
>   Size-related characters are homoplasious, as is the very condition of a
> ziphodont tooth morphology. Would you leave or have these in your matrix?

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.

> *Archaeopteryx* lack rib facets, as
> even do other maniraptorans sans birds. That the nesting oviraptorid
> (refered to *Citipati* on the basis of unpublished data) and
> *Velociraptor* (fragementary sternum with three broken "ventral ribs" on
> one side, and none actually touching the sternum itself) do not show, in
> the absent of actual facets on the sternae, the actual number of sternal
> ribs.

The single known sternum of Archaeopteryx is poorly preserved and near
certainly not completely ossified.  Other theropods do have sternal rib
facets, even those as basal as Gorgosaurus (Lambe, 1917).  I will agree
Velociraptor may have had more than three sternal ribs, as the lateral
sternal edges are still unknown.

> My point was that this value may not be
> of any phylogenetic utility. Both troodontids and ornithomimosaurs have a
> hollow parasphenoid rostrum (*Sinornithosaurus* is said to as well) but
> *Sinovenator* does not; it's still useful for troodontids unto themselves,
> as for ornithomimosaurs. Spinosaurs and the basal ornithomimosaur
> *Pelecanimimus* have seven premaxillary teeth, another character that is
> meaningless to coelurosaurian phylogeny. Your contention that "if any two
> taxa have it" must be considered on the phyletic space in an anlysis. If a
> character contributes no information, it should be culled. This does not
> mean it cannot be included for later analysis. But presently, in theropod
> systematics, the robust-gracile dichotomy is not diagnostic to taxon and
> cannot be used for phylogeny as shown by Colbert, Raath, and Padian and
> Gauthier.

Almost EVERY character is of potential phylogenetic utility.  Excluding
characters a priori based on assumed convergence is a horrible practice.
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.
Also, whether Sinovenator's parasphenoid rostrum is hollow is unknown.  It
lacks an expanded parasphenoid rostrum, as does Sinornithosaurus.

> <So your theory is that terrestrial taxa will have more robust fibulae
> than arboreal/scansorial ones?>
>
>   I said nothing about fibulae. Fibulae may become reduced not as an
> arboreal function but as a relation to tibial compression; the presence of
> a single element in the shin that effects the autopodium decreases splay
> during the compression phase in a walk. Cursors will either loose the
> fibula, or fuse it to the tibia;

Here you go again with the habit of changing topics.  Let's copy and paste
the whole thing (for anyone who is still reading through this mess)-
See http://www.cmnh.org/fun/dinosaur-archive/2002Apr/msg00553.html for-

>Me- How are many taxa and a list of vales then?  See a clear increase in
fibular width (as a percentage of tibial width; on right in parentheses)
with increasing size (represented by femoral length to left)?  I don't.

>You- I thought I covered this at the end of the post. Robusticity indexes
and
neoterrestrial structures are expected. Trying to use them to explain
avialian conditions is going to fall flat if these appear to be related to
cursoriality and scansoriality. Tree-huggers have delicate limbs, walkers
don't. Once the deinonychosaurs hit the ground, they required and increase
in the robusticity to effect their larger size. *Comspognathus* was not so
fortunate as no theory currently puts it into a guild where its direct
ancestors were arboreal, as in Xu et al.s theory.

Hmm.  What do we have here?  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?

>   *Avimimus* does not have a robust fibula. The distal end is fused to the
> tibia and tarsus ... the proximal end is reduced and at one point it was
> conjectured (Norman, 1990, I think) that the fibula was in fact in two
> parts, the proximal caput and the distal fused portion. They are probably
> one element, and it is very, very slender. Ornithomimosaur and tyrannosaur
> fibulae are fairly sturdy, not as expected in many avian and quadrupedal
> cursors, 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. ;-)  Now I may be getting a bit
harsh.  :-)  But seriously, this particular character is getting examined
too closely for me to feel comfortable using my old ratios.  I'll measure
some new ones with better methods, then we can continue.

>   And that of *Sinornithosaurus* is completely unique to it, unlike the
> third condyle in avian jaws, or *Erlikosaurus*' extra apparent "condyle."

Correct.  Luckily, the presence of this in Sinornithosaurus didn't support
any phylogeny.

> <"The condyle, or the shaft? I see the element is rather flattened in
> aspect, but this does not appear to be the same in pygostylians, which
> expand the shaft proximal to the distal terminus (condyle). Archaeopteryx
> lacks it, however, as does Microvenator.">
>
>   But the second metacarpal is known, as is ... apparently, the first
> phalanx of the second digit. Which lacks the flange. I may be wrong, but
> there is no apparent flattening.

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.

> <But we're talking about MANUAL phalanx II-1, not pedal phalanx II-1.
> Remember, you were just talking about the manual phalanx being flattened
> in pygostylians.  Regardless of whether you meant Microvenator or -raptor,
> neither has a described manual phalanx II-1.>
>
>   We were talking about both.

No we weren't.  More of your switching topics problem.  Look at our actual
exchanges-

>Me- expanded manual phalanx II-1;

>You- In what manner is it expanded?

>Me- The distal end is lateromedially expanded, as in pygostylians.

>You- The condyle, or the shaft? I see the element is rather flattened in
aspect, but this does not appear to be the same in pygostylians, which
expand the shaft proximal to the distal terminus (condyle).
*Archaeopteryx* lacks it, however, as does *Microvenator*.

>Me- The shaft.  Paul actually used this quite prominently in his SVP
presentation, it's easier to see in cf. Sinornithosaurus.  Archaeopteryx
probably does lack it.  That's why it's in the "characters also found in
more derived birds, but not Archaeopteryx" section of my list.  Again with
the unknown Microvenator elements.  Perhaps you mean Microraptor, but
phalanx II-I isn't known in that genus either.  Could you be referring to
the new skeletons (have an early copy of the new AMN paper perhaps)?

* 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.

>You- Ah wonderful ...  see above about the Micro-dino names. It's not
pdII-1
that's nessesary for evaluation of the heel, however, it's pdII-2.
Conversely, this may also indicate the presence of the greater arc on the
distal pdII-1, but that's not really the point.

>> Ask questions.
>
> <Okay.  Why did you suddenly switch from manual phalanx II-1 flattening to
> pedal phalanx II-2 proximoventral heels?  Why did you state Microraptor
> lacks a flattened manual phalanx II-1.  Do you have an early copy of the
> new AMN description of Microraptor?>
>
>   We were talking about both.

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?

> <I agree that neither side is obviously correct at this point.
> Sinornithosaurus could be a basal deinonychosaur, but I feel the evidence
> for it being a basal avialan is at least equally strong.  Sinovenator does
> influence a few of my characters, but not all.>
>
>   Have you fully coded it?

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.

Mickey Mortimer