Harris, Jerald | 1 Feb 02:55 2007

New-ish Papers

Hi All -
     First, some new papers from Chinese journals.  Perhaps most interesting of this batch is:

Liu, Y., Liu, Y., and Zhang, H. 2006. LA-ICPMS zircon U-Pb dating in the Jurassic Daohugou Beds and
correlative strata in Ningcheng of Inner Mongolia. Acta Geologica Sinica (English Edition)
80(5):733-742. 
ABSTRACT: LA-ICPMS Zircon U-Pb dating is applied to volcanic rocks overlying and underlying the
Salamander-bearing bed in the Daohugou beds of Ningcheng in Inner Mongola and Reshuichang of Lingyuan
and Mazhangzi of Jianping in western Liaoning. The results indicate that the youngest age of the rocks in
Daohugou of Ningcheng is 158 Ma, and the oldest one is 164 Ma. Synthesized researches indicate that the
salamander-bearing beds in Daohugou of Ningcheng, Reshuichang of Lingyuan and Mazhangzi of Jianping
were developed in the same period. The Daohugou beds were formed in the geological  age of 164-158 Ma of the
middle-late Jurassic. Whilst, the Daohugou beds and its correlative strata should correspond to the
Tiaojishan Formation (or Lanqi Formation) of  the middle Jurassic in northern Hebei Province and western
Liaoning Province, based on the disconformity between the Daohugou beds and its overlaying beds of the
Tuchengzi Formation of Late Jurassic and the Jehol Beds of early
 Cretaceous, and the disconformity between the Daohugou Beds and its underlying Jiulongshan Formation,
which is composed of conglomerate, sandstone, shale with coal and thin coal beds.

Also:

Cheng, X., and Gao, R. 2006. Simulation of the leg mechanism of a bipedal dinosaur. Journal of Mechanical
Transmission 30(4):11-13.

     All in Chinese, so I can't read a word of it except for the math formulae, none of which make sense to me, but...

Fang, X.-S., Zhang, Z.-J., Lu, L.-W., Han, Y.-J., Zhao, X.-J., and Li, P.-X. 2006. Collision between the
Indian plate and the paleo-Asian plate and the appearance of Asian dinosaurs. Geological Bulletin of
China 25(7):862-873.

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Michael Mortimer | 1 Feb 08:59 2007
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Re: Richardostesia teeth

Jaime A. Headden wrote-

>Michael Mortimer (mickey_mortimer111 <at> msn.com) wrote:
>
><Because they both have very tiny serrations.  So does Nuthetes, which I
>believe falls into the range of Richardoestesia morphotypes.>
>
>   It is not so much the size of the serrae as the shape of the serrae, 
>being
>low, and nearly quandrangular, along with size distribution along the 
>carinae.
>The shapes oft he teeth are also very coincident, with all teeth attributed 
>to
>this genus being relatively straight with minimal recurvature. The *R.
>isoceles* teeth are just less recurved and in fact less recumbent than the
>teeth attributed to *R. gilmorei*.

Denticle shape is not uniform/distinct in the genus, as noted by Sankey et 
al. (2002) for R. gilmorei- "Denticle tips can be slightly pointed, rounded, 
or flattened."  While she describes R. isosceles as- "Denticle tips are 
straight or slightly rounded, but not pointed."
Similarly, all teeth referred to Richardoestesia are not relatively 
straight.  Again, describing R. gilmorei- "Isolated teeth vary in curvature 
from almost completely straight (0.1 mm curvature) to strongly recurved (0.7 
mm curvature)."
The denticle size distribution along the carinae for R. gilmorei ("Denticle 
size varies slightly along the carinae, with smaller ones at the base and 
tip.") is not distinct from Saurornitholestes ("Denticle size varies along 
the carina, they tend to be smaller at the base and tip of teeth.").  R. 
isosceles has a different size distribution though- "Posterior denticles are 
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evelyn sobielski | 1 Feb 10:41 2007
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Re: Livezey and Zusi's big bird morph analysis [...]


> > - given the sheer amount of chromosomal
> rearrangements
> > present in Accipitridae, one could actually ponder
> > whether it is wise to include them at all -
> 
> That doesn't matter for the mitochondrial genome.

True, but at the presently available amount of
sequenced mtDNA sequences, signal is probably too
noisy to be of much use. Doesn't matter for this
analysis though.

> > As regards their phylogeny:
> > (Isn't their use of Neoaves fairly unusual?)
> 
> Livezey & Zusi use it just like everyone else: it's
> the sister-group of 
> Gallanseres.

kk, I think it left me wondering because it's nothing
I worry much anymore these days. There is not much to
say about it in any case; even "stuff" like Laornis
can usually be firmly placed therein.

> > Group B is generally well-supported, though the
> timing
> > of the galliform/anseriform split is debatable,
> 
> Do you mean Fig. 10B = Fig. 13 (which is
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evelyn sobielski | 1 Feb 10:49 2007
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Re: Livezey and Zusi's big bird morph analysis [...]


> As for the proposed grebe-loon clade, L & Z point
> out that this clade does 
> not include *all* foot-propelled diving birds, like
> hesperornithids for 
> example.  So it's not just a case of convergence
> being mistaken for a 'real' 
> (synapomorphic) relationship.

But the case for convergence confounding analyses has
been made, time and again, for exactly this clade. It
is THE showcase example where parsimony is likely to
run into a wall*, and has been since more than a
decade (in fact, try doi:10.1007/BF01908745). This
cannot be dismissed out of hand. Basically they
reiterate a cold case; this is not good.

Eike

* Especially in such large-scale analyses, where the
data set cannot be sufficiently fine-grained because
it could then not be applied to many other taxa. A
morphological analysis of foot-propelled divers that
is good (IMHO) would run into problems as soon as it
comes to outgroup selection, because the character set
would include a load of F-PD apomorphies.

		
___________________________________________________________ 
Telefonate ohne weitere Kosten vom PC zum PC: http://messenger.yahoo.de
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Mike Taylor | 1 Feb 10:52 2007

Re: Medullary Bone Distribution in Archosaurs

Jura writes:
>>>> Do we know anything about the presence or absence of medullary
>>>> bone in Sauropods, Pterodactyles, or the bird-hip dinosaurs
>>>> (ducksbills, ceratopsians, etc.)?
>>> 
>>> Unknown until someone breaks a couple of sauropod and
>>> ornithischian bones in hopes of finding original cellular
>>> material.
>> 
>> Sounds like a project for somebody, maybe PHD paper?
> 
> Possibly. I sure wouldn't want to be the one having to
> write the research proposal for that one.
> 
> "In order to determine medullary bone presence in
> other members of Dinosauria, it is necessary to look
> for the presence of preserved original cellular
> material. In order to do this, the rending of limb
> bones in the more common members of the Hell Creek
> Sauropodan and Ornithischian fauna, would need to be
> done."

There are loads of broken sauropod long-bones out there: anything that
big is subject to big weight stresses, and tends to break easily.
It's just that people keep gluing 'em together.  Matt Wedel, being a
pneumaticity specialist, feels that intact sauropod vertebrae are much
less interesting then broken ones ... so keep him away from your
collections!  :-)

 _/|_	 ___________________________________________________________________
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Mike Taylor | 1 Feb 12:10 2007

footage of Tyrannosaurus biting into another animal anyone?

Mickey Rowe;893-2446 writes:
 > An Associate Producer at National Geographic is looking for
 > animation of a Tyrannosaurus attacking something, preferably a
 > Triceratops.  They specifically want to show the mouth as it's
 > biting into another animal.  I already suggested the "Walking with
 > Dinosaurs" episode "The Truth about Killer Dinosaurs".  She
 > mentions that it's owned by Discovery Channel and says that they
 > can't use it (I don't know whether or not that's a blanket
 > statement meaning they can't use anything from the Discovery
 > Channel).  She indicated that the WWD episode would be perfect if
 > they could use it.  She says they do have a budget for stock
 > footage but don't have time to commission something new.
 > 
 > Anybody have any other ideas?

The _Prehistoric Park_ DVDs have a fair bit of footage of tyrannosaurs
biting various things, including each other.  And, by the way, I
highly recommend them to anyone who isn't too oh-it's-not-scientific
to enjoy that kind of thing.

 _/|_	 ___________________________________________________________________
/o ) \/  Mike Taylor    <mike <at> indexdata.com>    http://www.miketaylor.org.uk
)_v__/\  "Klingon function calls do not have 'parameters' - they have
	 'arguments' - and they ALWAYS WIN THEM." -- Klingon Programming
	 Mantra

Dino Guy Ralph | 1 Feb 17:56 2007
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Picon

RE: New-ish Papers

Jerald Harris mentions:
Liu, Y., Liu, Y., and Zhang, H. 2006. LA-ICPMS zircon U-Pb dating in the
Jurassic Daohugou Beds and correlative strata in Ningcheng of Inner
Mongolia. Acta Geologica Sinica (English Edition) 80(5):733-742.

(From abstract):
"The Daohugou beds were formed in the geological age of 164-158 Ma of the
middle-late Jurassic."

If this sticks, then _Epidendrosaurus_, _Pedopenna_, and _Jinfengopteryx_
predate _Archaeopteryx_.  No "temporal paradox" here!  

Dino Guy Ralph
Docent at the California Academy of Sciences
Dinosaur and Fossil Education
Member of the Society of Vertebrate Paleontology

Danvarner | 1 Feb 19:29 2007
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Re: Tyrannosaurus Trivia Question

>From photos in Lowell Dingus' book, _Next  of Kin_ (a must for artists), I've 
narrowed down the switch from three to two  digits in the AMNH mount of 
Tyrannosaurus to somewhere between 1921 and 1927. A  bit earlier than I had 
originally suspected. DV  

Danvarner | 1 Feb 21:40 2007
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Another look at sauropod posture

http://palaeoblog.blogspot.com/2007/02/pectoral-girdle-reconstruction-in.html 

Jaime A. Headden | 1 Feb 22:47 2007
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Re: Richardostesia teeth

Michael Mortimer (mickey_mortimer111 <at> msn.com) wrote:

<Denticle shape is not uniform/distinct in the genus, as noted by Sankey et al.
(2002) for R. gilmorei- "Denticle tips can be slightly pointed, rounded, or
flattened."  While she describes R. isosceles as- "Denticle tips are straight
or slightly rounded, but not pointed." Similarly, all teeth referred to
Richardoestesia are not relatively straight.  Again, describing R. gilmorei-
"Isolated teeth vary in curvature from almost completely straight (0.1 mm
curvature) to strongly recurved (0.7 mm curvature)." The denticle size
distribution along the carinae for R. gilmorei ("Denticle size varies slightly
along the carinae, with smaller ones at the base and tip.") is not distinct
from Saurornitholestes ("Denticle size varies along the carina, they tend to be
smaller at the base and tip of teeth.").  R. isosceles has a different size
distribution though- "Posterior denticles are ... uniformly-sized along
tooth,">

  I did not mention the issue of potential conflation of sampling for *R.
gilmorei* as it appeared Tom Holtz had previously done so in this very thread,
and I had brought up the issue of possible taxonomic variability (as have
others in print) among the specimens in a previous incarnation of this topic.
The holotype jaws have teeth that are, on the other hand, very similar to one
another, have little recurvature, and have serrae that decrease in size toward
the base of the crown, as towards the apex.

<Indeed, Sankey later states "Richardoestesia isosceles is included in the
genus Richardoestesia because of the presence of small denticles. However, the
shape of the denticles in Richardoestesia gilmorei and isosceles is
different.">

  Which is only indicative perhaps of taxonomic variability. To wit, Sankey;'s
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Gmane