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Ben Creisler | 26 May 17:45
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Tetrapods from Permo-Triassic boundary in Russia

From: Ben Creisler
bcreisler <at> gmail.com

A new paper in Paleontological Journal:

A. G. Sennikov and V. K. Golubev (2012)
On the faunal verification of the Permo-Triassic boundary in
continental deposits of eastern Europe: 1. Gorokhovets-Zhukov ravine.
Paleontological Journal 46(3): 313-323
DOI: 10.1134/S003103011203015X
http://www.springerlink.com/content/ug2835240107184u/

A reference section of the Permian and Triassic continental deposits
of the Zhukov ravine near the town of Gorokhovets (Vladimir Region) is
described and new tetrapod localities are characterized. The position
of the Permian-Triassic boundary in this section is recognized and its
faunal substantiation based on vertebrates is provided for the first
time. The Zhukov ravine section is unique in the fact that it shows a
thick stratigraphically continuous succession of the Permo-Triassic
boundary beds, with three successive tetrapod zones: the terminal
Permian Chroniosuchus paradoxus and Archosaurus rossicus zones and the
Early Triassic Tupilakosaurus wetlugensis Zone.
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Ben Creisler | 26 May 06:56
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Andalgalornis (phorusrhacid "terror bird") neck flexibility

From: Ben Creisler
bcreisler <at> gmail.com

New in PLoS ONE:

Claudia P. Tambussi, Ricardo de Mendoza, Federico J. Degrange &
Mariana B. Picasso (2012)
Flexibility along the Neck of the Neogene Terror Bird Andalgalornis
steulleti (Aves Phorusrhacidae).
PLoS ONE 7(5): e37701.
doi:10.1371/journal.pone.00377
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0037701

Background

Andalgalornis steulleti from the upper Miocene–lower Pliocene (≈6
million years ago) of Argentina is a medium-sized patagornithine
phorusrhacid. It was a member of the predominantly South American
radiation of ‘terror birds’ (Phorusrhacidae) that were apex predators
throughout much of the Cenozoic. A previous biomechanical study
suggests that the skull would be prepared to make sudden movements in
the sagittal plane to subdue prey.

Methodology/Principal Findings

We analyze the flexion patterns of the neck of Andalgalornis based on
the neck vertebrae morphology and biometrics. The transitional
cervical vertebrae 5th and 9th clearly separate regions 1–2 and 2–3
respectively. Bifurcate neural spines are developed in the cervical
vertebrae 7th to 12th suggesting the presence of a very intricate
(Continue reading)

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Ben Creisler | 26 May 06:54
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Sauropod tracks impact on lagoon sandstone in Australia

From: Ben Creisler
bcreisler <at> gmail.com

New in PLoS ONE:

Tony Thulborn (2012)
Impact of Sauropod Dinosaurs on Lagoonal Substrates in the Broome
Sandstone (Lower Cretaceous), Western Australia.
PLoS ONE 7(5): e36208.
doi:10.1371/journal.pone.0036208
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0036208

Existing knowledge of the tracks left by sauropod dinosaurs (loosely
‘brontosaurs’) is essentially two-dimensional, derived mainly from
footprints exposed on bedding planes, but examples in the Broome
Sandstone (Early Cretaceous) of Western Australia provide a
complementary three-dimensional picture showing the extent to which
walking sauropods could deform the ground beneath their feet. The
patterns of deformation created by sauropods traversing
thinly-stratified lagoonal deposits of the Broome Sandstone are
unprecedented in their extent and structural complexity. The stacks of
transmitted reliefs (underprints or ghost prints) beneath individual
footfalls are nested into a hierarchy of deeper and more inclusive
basins and troughs which eventually attain the size of minor tectonic
features. Ultimately the sauropod track-makers deformed the substrate
to such an extent that they remodelled the topography of the landscape
they inhabited. Such patterns of substrate deformation are revealed by
investigating fragmentary and eroded footprints, not by the
conventional search for pristine footprints on intact bedding planes.
For that reason it is not known whether similar patterns of substrate
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Don Ohmes | 26 May 00:45
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Microraptor hanqingi, new species from China.

 > Again, I actually like the idea - since you're the one who pointed it 
out here, I was hoping you had some suggestions for what we'd predict if 
tree-roosting was indeed important to paravians.

The idea was never advanced by me as a testable lifestyle for any 
particular fossil specimen -- that would be a "misunderstanding" -- but 
it falsifies the idea that an animal evolving flight in tree-down 
gliding-first mode will by evolutionary logic show "arboreal 
adaptations" in its skeleton -- beyond the basic capacity to climb a tree...

I suppose predictions made by tree-roosting might include 1) limited 
upstroke early on (that is, even after the appearance of a sophisticated 
gliding wing), 2) that the perching foot would appear subsequent to 
powered flight (full upstroke), not before -- and 3) the capability of 
climbing vertically.

One note -- controlled climbing up is easier than climbing down -- and 
in the hoatzin type wing-claw model, climbing down would appear to be 
problematic, which makes parachuting/gliding useful.

In any case, I am unsure that these are unique predictions, and would be 
useful in "proving" tree roosting -- although I suppose in sum they 
might be a start.

Given that the possibility of a tree-roosting lifestyle falsifies 
certain assertions about the relevance of "arboreal adaptions" to bird 
flight evolution, I think any statements that the "discussion" was not 
fruitful are wrong.

 > If your assertion is, instead, that we'd see no difference in the
(Continue reading)

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Jason Brougham | 25 May 23:38
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FW: Microraptor hanqingi, new species from China.

I, for one, think that basal paravians and avialans were not highly arboreal. But there are at least three
features that suggest that something other than running fast on the ground had become a new priority in the
biology of basal paravians.

One is the very long leg wings, which Xu hypothesized were in conflict with fast running. This is hard to test.

Two are the longer penultimate phalanges, seen also, I believe, in Xiaotingia.

Three is the evolution of the reversed hallux. It is at least slightly reversed by Jeholornis and  more so, as
well as longer and stronger, by Changchengornis. I do assume that this indicates that being good at
gripping branches became important to their survival early in the evolution of the modern flight apparatus.

I guess then a testable prediction is that, if the forms in which incipient flight evolved were not using
tree habitats at all (if strict ground up is correct), the 1st digit should begin its long sequence of
adaptations AFTER the flight apparatus is assembled.

Instead I interpret the descent of the hallux to lie close to the other toes in Microraptor, and more so in
Epidendrosaurus and Xiaotingia to possibly indicate the first steps of selection for branch walking.
After these incipient stages there is a long and complex radiation of avialans with increasing rotation
of the hallux.

The small body size, large wings, showy tails, feathered legs, long penultimate phalanges, and
descending hallux of basal paravians could be seen as consistent with animals that were using tree
habitats some of the time and adapting to those habitats. If the descending hallux and penultimate
phalanges have nothing to do with branches, and small animals can run just fine with long wings on their
legs, then this is not evidence for branch walking at all. But maybe then the burden lies with others to
explain the very long and diverse series of morphological changes in Mt I.
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Jason Brougham | 25 May 23:37
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FW: Microraptor hanqingi, new species from China.


I second Dr. Habib on that. Some papers on quail and starlings showed that something like 90% of their launch
velocity came from leaping with their legs, from a  standstill, and only 10% from their modern pectoral
flight apparatus. Until then I never imagined the legs provided so much thrust. The kagu is said to start at
a  standstill, leap up with its legs, and glide downhill, but I investigated that and it is suspect. We'd
have to test one in a  zoo to see if they can really do it without flapping.
________________________________________
From: owner-DINOSAUR <at> usc.edu [owner-DINOSAUR <at> usc.edu] on behalf of Habib, Michael [MHabib <at> Chatham.edu]
Sent: Friday, May 25, 2012 4:36 PM
To: Augusto Haro
Cc: d_ohmes <at> yahoo.com; "dinosaur <at> usc.edu"@listproc.usc.edu
Subject: Re: Microraptor hanqingi, new species from China.

The inability of Archaeopteryx to flap is actually quite debatable, but regardless, there are many other
ways to use wings than gliding, even without powered flight. Incidentally, if it launch from the ground
(huge if) there's no particular reason to expect it ran to do so.

--Mike

On May 25, 2012, at 3:09 PM, Augusto Haro wrote:

> 2012/5/25 Habib, Michael <MHabib <at> chatham.edu>
>
> Also, for all of the individuals in the current thread: we should be sure to give good cause at each step for
putting paravians in trees to begin with.  The potentially intuitive nature of arboreal proto-flight
does not constitute good cause.
> In my case, when I tought best of the hypothesis of tree-down origin of avian flight, my main reasons were:
>
> 1- Reading that Archaeopteryx could not flap, being thus forced to glide or soar (if such a form got into the
air at all), coupled with the impression that these wings had to be used to travel on air away from the floor
(Continue reading)

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Soledad Esteban | 25 May 11:04

Geometric Morphometrics courses

Dear colleagues:

This e-mail is to inform you of some courses on Geometric Morphometrics, which may would be of your
interest. I would appreciate if you could distribute this information between your colleagues:

"Introduction to Geometric Morphometrics". June 12-15, 2012. Instructors: Dr. Chris Klingenberg
(University of Manchester, UK) and Dr. Jesús Marugán-Lobón (Universidad Autónoma de Madrid). Just
5 places left. More information at: http://www.transmittingscience.org/introduction_to_gm.htm

“3D Geometric Morphometrics”. July 17-20, 2012. Instructor: Dra Melissa Tallman (CUNY/AMNH, New
York). Early registration until May 31. More information at: http://www.transmittingscience.org/3d_gm.htm

“Geometric Morphometrics and Phylogeny”. September 4-7, 2012. Instructor: Dr. Chris Klingenberg
(University of Manchester, UK). More information at: http://www.transmittingscience.org/gm_and_phylogeny.htm

For any questions: courses <at> transmittingscience.org.
These courses will be held in the premises of Sabadell of the Institut Català de Paleontologia Miquel
Crusafont (Barcelona, Spain). They are co-organized by Transmitting Science and el Institut Catalá de
Paleontologia Miquel Crusafont. 

Best regards

Soledad De Esteban Trivigno
Area de Paleobiología
Institut Català de Paleontologia
Edifici ICP, Campus de la UAB
08193 Cerdanyola del Vallès
Barcelona. Spain
00-34-935868334
www.icp.cat
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Jason Brougham | 25 May 05:27
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FW: Microraptor hanqingi, new species from China.


________________________________________
From: Jason Brougham
Sent: Thursday, May 24, 2012 11:27 PM
To: tijawi <at> gmail.com
Subject: RE: Microraptor hanqingi, new species from China.

You are right and we agree that arboreality in basal paravians is not proven and should not be assumed. I have
an open mind as to whether basal paravians were arboreal or terrestrial, as well as the possibilities of
mixed habitat, including roosting. I certainly do not think there is conclusive evidence for roosting in
these early forms, but I have been keenly interested to see how many of the most unlikely modern birds,
including highly cursorial ones and even some of the few birds with no halluces, can roost and even nest in trees.

I wonder why you say that galliforms are poor analogs for basal paravians? The only aspects of the latter
bauplan you named are long necks and long legs and leg proportions. if cursorial theropods like turkeys
aren't good analogs for cursorial theropods like, say, Caudipteryx, then what are? And what living
animal would you say is the best analog for Archaeopteryx?

Perhaps you could strengthen your arguments by explicitly listing those differences between the bauplan
of basal paravians and modern birds that may make it impossible or unlikely for the former to roost in trees.

You did say that petrels have the benefit of being descended from a  perching bird. This benefit, I guess, in
your context is simply being relatively squat. But Epidendrosaurus may be equally or even more short
necked and short legged compared to petrels. And how does a long - necked bauplan keep an animal from
roosting anyway? No non-avian theropod has legs as disproportionately long as the Secretarybird,
Sagittarius. Yet they perch quite readily (albeit with good halluces).

Galliforms have a rudimentary hallux that is elevated above the other toes, but it can usually touch the
ground. Nonetheless, I have many photos of turkeys roosting in trees, adopting postures where the hallux
is held clear and does not oppose the other toes
(Continue reading)

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Ben Creisler | 24 May 18:11
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K/T '3-meter gap' controversy

From: Ben Creisler
bcreisler <at> gmail.com

A new online paper:

A.J. (Tom) van Loon (2012)
Time and space in stratigraphy: The ‘3-m gap’ story.
Proceedings of the Geologists' Association (advance online publication)
http://dx.doi.org/10.1016/j.pgeola.2012.03.008
http://www.sciencedirect.com/science/article/pii/S0016787812000296

Even for earth scientists it appears difficult to keep in mind that a
sedimentary succession does not form due to accumulation at a constant
rate, but that long periods of slow accumulation may alternate with
short phases of event sedimentation and/or shorter or longer
time-spans of non-deposition or even erosion. An example of this
incorrect way of thinking is a recently published article in which it
is postulated that the find of a ceratopsian brow horn only 13 cm
below the K/T boundary in the Hell Creek Formation (Montana, USA)
proves that dinosaurs did not become extinct before the K/T impact. It
is argued why the postulated consequence (closure of the so-called 3-m
gap: a zone of some metres thick underneath the K/T boundary in which,
thus far, no dinosaur remnants had been found in the USA) is based on
incorrect presumptions, particularly the relationship between time and
space.
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Jura | 23 May 20:03
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Phylogeny of Ankylosaur Dinosaurs - PDF request

Hi all,

Once again early access has prevented my institution from getting what we normally get.

If anyone has access to the latest paper on ankylosaur systematics, I would really appreciate a copy of it.

Thank you,

Jason
 

Thompson, R.S., Parish, J.C., Maidment, S.C.R., Barrett, P.M. 2012. Phylogeny of the Ankylosaurian
Dinosaurs (Ornithischia: Thyreophora). J.Syst.Paleo. Vol.10(2):301-312
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Ben Creisler | 23 May 19:38
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Chechnya "dinosaur eggs" officially debunked

From: Ben Creisler
bcreisler <at> gmail.com

Alas, the supposed giant "dinosaur eggs" from Chechnya are only boring rocks--

http://www.rt.com/news/chechen-eggs-rocks-photos-996/
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Gmane