[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: Coelurosaur Analysis Update featuring Buitreraptor
Michael Mortimer (firstname.lastname@example.org) wrote:
<This last point is important. Many people don't realize that making an
ordered character multistate serves to give it greater weight. Say you have
"pubic angle - <90 degrees posterior (0); >90 degrees posterior (1)". A basic
propubic vs. opisthopubic character. It takes one step to get from one extreme
to the other. Now add in mesopuby as state 1, and make opisthopuby state 2.
Because it's ordered, it takes 2 steps to get from propubic to opisthopubic now
(you have to go through mesopuby). You've just weighted pubic angle compared
to a bistate character. What's the solution? Corrective weighting. You need
to give pubic angle half the weight your bistate character has. Then it takes
the same amount of steps to get from one extreme to the other in both cases.
So I did this to all my characters.>
As was argued by Makovicky et al. in the *Buitreraptor* paper (supplementary
info), pubic orientation needs to be quantified grossly. They, for example, use
the proximal orientation to demonstrate position. What other positions and how
are they coded for, are used? Does the pubic boot contribute to the anterior
orientation of oviraptorid pubes? If so, so too must long-booted taxa like
tyrannosaurids also be so coded. The proximal pubic shafts in msot oviraptorids
are caudally oriented, as are some *Allosaurus* pelvises and tyrannosaurine
pelvises. This would tell me the condition must be considered universal among
these to get any meaningful data from them. To ignore this and just plop the
distal extent as the true meaningful metric, for example, is actually coding
for pubic length anterior to the main axis of the pubic shaft as well as distal
inflection of the pubic shaft from the proximal portion. Because of this, my
codings for pubic orientation are MUCH more split up as a set of variable
characters, 3-4 of them, including pubic boot, long pubic axis orientation,
proximal and distal pubic orientations. "Opisthopuby" and "Mesopuby" and
"Propuby" seem to be complexes, not singular conditions as previously throught.
And, a comment on character transformations: Has anyone tried noting that all
characters are of equal weight and all character transformations are of equal
weight, the possibilities of transformation from one state to another without
having to correspond to an intermediate state may be just as likely in one step
of transformation as two, or more? Biology does not tell us that sacral
incorporation MUST be sequential by 1's, but can issue in leaps and bounds. Two
dorsals can fuse, for example, prior to fusion to the sacrum, causing a sacral
count to jump from 5, say, to 7, without going through incoporating a sixth
element separately. Similarly, tooth loss can be as simple as preventing tooth
buds from forming, rather than sequential loss or regionalization of tooth
expression, causing character transformation sequences to be more random.
Sequencing and ordering characters and even weighting them can lead to
massively assumed character support for clades without respect to studying the
transformation or incorproration (and thus support for) a clade. Similarly, has
anyone ever tested how a reversal of a condition can be both actual as well as
an acquired trait on it's own? The mutation that causes a loss of expression of
tooth buds, for example, can easily be overridden by a mutation that suppresses
the tooth buid supressor, causing tooth-buds to form again. Our matrices call
this a reversal, but if adding in the agents, we find it's a separate, acquired
trait. Thus I argue for equal weight and unordering of characters to limit
assumptions on transformation sequences.
On to the tree....
| | `--Calamosaurus
So *Megaraptor* isn't a carcharodontosaur why?
Jurassic *Tyrannosaurus*? *Bagaraatan* as a synonym of a juvenile, MAYBE, if
it were another species, but likely not as a synonym of *T. baatar*. This is
begging the cake.
| `--+--IVPP V11309
| | `--Nomingia
| | `--Protarchaeopteryx
| | `--+--Nemegtia
| | `--Heyuannia
| | `--+--Citipati
| | `--Deinocheirus
There is so much going on here that is totally wonky. Lessee: Lü and Hou
proposed that IVPP V11309 was avian because of the foramina of the caudal
centra was an avian feature; *Sapeornis* and *Omnivoropteryx* are probably
synonyms in my opinion, but their position at the base of Oviraptorosauria
along with *Nothronychus* is begging incredulity who stole the cake, seeing
that the two groups are so highly uncomparable in their anatomies. What
characters link these? *Therizinosaurus* and *Deinocheirus* in the
Oviraptorosauria makes me think of the Deinocheirosauria from Barsbold, but
aside from the huge claws and proportions therein, what connects these taxa
here and not to, say, therizinosauroids proper and Ornithomimosauria? I
understand that Makovicky et al. proposed that *Deinocheirus* be excluded, but
since I can't get my hands on this book for some time, IU must ask for their
verbatim evidence, if at all possible.
yeah, got *Parvicursor* as an alvarezsaur, but also *Erliansaurus*!
| | | `--Wellnhoferia
| | `--+--Rahonavis
| | `--+--Buitreraptor
| | `--Scansoriopteryx
*Epidendrosaurus*, actually, is the senior synonym, if they are synonymous.
The non-use of *Epidendrosaurus* here seems to suppose their synonymy in the
matrix, so, even allowing for Czerckas' pleas for a questionably dated
publication, the _Naturwissenschaften_ publication was technically published
first since it was done so online well in advance to the print copy, and thus
conforms to the ICZN.
| `--+--IGM 100/44
Why is *Yixianosaurus* a troodontid? A rather long-armed one, at that!
| `--+--+--Microraptor gui
| | `--+--Microraptor zhaoianus
| | `--Cryptovolans
Why is *Ricardoestesia* (both species used? Mandibular characters coded as
well?) a dromaeosaurid? I would think the denticle morphology excludes this....
"There seem to be some "improvements"
- "Alashansaurus" and Labocania are sister taxa.
- 'Iliosuchids' are tyrannosauroids.
- Saurornithoides is monophyletic (finally!)."
Why are these improvements? I am not sure the monophyly of *Saurornithoides*
is entirely warranted, given the variation between the two animals' type
"Some changes which may have support-
- Deinocheirus no longer an ornithomimosaur (Makovicky et al., 2004).
- Sapeornis and Omnivoropteryx as oviraptorosaurs.
- Alvarezsaurids are paravians (the first time it's ever happened in my
- Jinfengopteryx sister to Eumaniraptora (and incidentally close to both
troodontids and archaeopterygids)
- Mei and Asian long-tailed birds as basal deinonychosaurs."
What support? I had asked above why is *Deinocheirus* not an ornithomimosaur,
but I fear the alternative isfar more bizarre than if it were an
ornithomimosaur. Again, the skeletal features in *Sapeornis* or its probable
synonym seem utterly too avian, so what makes them (and *Nothronychus*,
*Therizinosaurus* and *Deinocheirus*) oviraptorosaurs? What puts Alvarezsauria
in Paraves? In fact the tree above puts Paraves within Deinonychosauria, so
that it seems that Metornithes includes Paraves/Deinonychosauria within
"And some things which would generally be considered wrong.
- Labocania no longer a tyrannosauroid.
- Aviatyrannis and Bagaraatan as tyrannosaurines.
- Borsti as a basal arctometatarsalian."
I am pretty sure that basal arctometatarsalians probably did not look as
clearly arctomet as other taxa. The condition of it's metatarsals are unknown,
so verification is not possible to date.
"- Nothronychus and Erlianosaurus not therizinosaurs."
Or rather, *Nothronychus* IS a therizinosaur: Where *Therizinosaurus* goes,
so too should any clade named based on it go, thus the Therizinosauridae and
Therizinosauroidea will either disappear for including Maniraptora, or be
required to be redefined. This would mean that Therizinosauroidea would also
include Oviraptorosauria, of which the giant taxa are now members, and that the
outliying group would need a new name (Alxasauridae and Segnosauridae (not to
mention Enigmosauridae) are available, for example).
"- Caenagnathidae, Microvenator and Oviraptor nested deeply within
Since Oviraptoridae and Caenagnathidae are, I believe, opposing stems, this
terminology is incorrect. Given the topology above, the names would apparently
| | `--Neimongosaurus
| |--other "caenagnathids"
*Oviraptor* is still at the base of Oviraptoridae, but the extensive
paraphyly of conventional Oviraptorosauria, including dispersal of oviraptorids
like *Heyuannia* and *Citipati* begs the question: Why? I'm doing a lot of
begging today, it seems. The also random placement of taxa with and without
crests may find an answer in sexual dimorphism, and there may be something to
it, but the postcranial features of these taxa do not seem to support this.
That and the insertion of birds, therizinosauroids, and an "ornithomimosaur"
within the grouping argues that this topology is probably most certainly
"- Byronosaurus very basal within Troodontidae."
Why is *Byronosaurus* generally considered wrong to be a basal troodontid?
The original matrix and the subsequent Xu et al. and Hwang et al. versions of
the TWG phylogeny found it to be basal, not derived, with respect to the root
and the "derived" troodontids like *Saurornithoides*.
Jaime A. Headden
"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)
Yahoo! Mail - PC Magazine Editors' Choice 2005