gmane.science.dinosaurs.general

Andalgalornis (phorusrhacid "terror bird") neck flexibility

Ben Creisler — 2012-05-26T04:56:34

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

Sauropod tracks impact on lagoon sandstone in Australia

Ben Creisler — 2012-05-26T04:54:03

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 hierarch

Re: Microraptor hanqingi, new species from China.

Robert Schenck — 2012-05-26T00:06:45

FWIW, I recently learned that a big controversy in herpetology right
now is whether to split up  the genus Mabuya, which is a type of
Skink. Some are adamantly opposed.

http://en.wikipedia.org/wiki/Mabuya

On Tue, May 22, 2012 at 11:46 AM, evelyn sobielski <koreke77< at >yahoo.de> wrote:

Re: Microraptor hanqingi, new species from China.

Habib, Michael — 2012-05-25T23:38:32

On May 25, 2012, at 6:45 PM, Don Ohmes wrote:


Cool.  Those seem consistent and reasonable.


I did not mean to imply the discussion was not fruitful, only that it could be more so with more specific predictions.


Got it.



Interesting thought.  You might be right on that; worth considering.

Cheers,

--Mike


Michael Habib
Assistant Professor of Biology
Chatham University
Woodland Road, Pittsburgh PA  15232
Buhl Hall, Room 226A
biologyinmotion< at >gmail.com
(443) 280-0181

Re: Microraptor hanqingi, new species from China.

Habib, Michael — 2012-05-25T23:36:14

On May 25, 2012, at 7:11 PM, Augusto Haro wrote:


Control functions (turning, braking, etc), leaping, WAIR, etc



In most cases, yes, a jump is more effective.  Even most running launches actually end in a leap.  If you want to see quick and easy evidence of this, take a look at stills of launching waterbirds - if they were actually building up launch speed and transitioning to wing-dominated propulsion gradually, then the water displacement (i.e. splashes) would get smaller over the course of the run.  In actuality, they tend to be quite consistent, until the last one - which is nearly always much larger than the rest.  Animals do not launch like airplanes.

Cheers,

--Mike


Michael Habib
Assistant Professor of Biology
Chatham University
Woodland Road, Pittsburgh PA  15232
Buhl Hall, Room 226A
biologyinmotion< at >gmail.com
(443) 280-0181

Re: Microraptor hanqingi, new species from China.

Augusto Haro — 2012-05-25T23:11:33

2012/5/25 Habib, Michael <MHabib< at >chatham.edu>





What would be these? I just imagine soaring, or some other function which
has nothing to do with aereal locomotion.




A jump would be better than running for a launch?
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Re: Microraptor hanqingi, new species from China.

Don Ohmes — 2012-05-25T23:08:19

Sounds good -- I personally will immediately throw my mind into neutral, 
and maybe plant some watermelons -- to pass the time while I am waiting...

Re: Microraptor hanqingi, new species from China.

Don Ohmes — 2012-05-25T23:02:18


That seems about as certain as anything...

I argue that the inverse does not hold, though -- a strict tree-down 
scenario would not logically (at least in the 'tree-roosting, 
ground-foraging' case) result in a perching or climbing pes prior to the 
evolution of full-on flight.

Microraptor hanqingi, new species from China.

Don Ohmes — 2012-05-25T22:45:55

 > 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 par

RE: Microraptor hanqingi, new species from China.

Jason Brougham — 2012-05-25T22:36:45

Sorry I just sort of blurted this out without thinking it through very carefully, so I welcome your help. 

In a hypothetical, strictly ground - up, ancestor of Avialae, wouldn't we expect the feet and legs to completely retain their ancestral form? Only when we get to powered flight will the little dickens' be able to drop down onto trees, and only then can they start adapting to branch gripping. 

But the actual sequence is that we get wings on arms and legs simultaneous with the descending Mt I. Then we move into Avialae, then we get partial reversal of hallux coincident with incipient improvements in the pectoral girdle (Jeholornis). Ultimately we get derived flight apparatus and fully reversed hallux.

OK, to improve on this we need to look at all known fossil taxa and see if there is a signal. Do the changes in leg and foot anatomy correlate with changes in flight apparatus, or precede them, or follow them, or is there no real signal. Does that work for testability for anybody?

With respect to anyone

Re: Microraptor hanqingi, new species from China.

Heinrich Mallison — 2012-05-25T22:19:23

Ah, papa ex cathedra next year?

I think it is just another symptom of your hubris that you now forbid
reasonable discussions. It is time you quit spaming the DML with your
unreasonable demands.
___________________________________
Dr. Heinrich Mallison
Abteilung Forschung
Museum für Naturkunde - Leibniz-Institut
für Evolutions- und Biodiversitätsforschung
an der Humboldt-Universität zu Berlin
Invalidenstrasse 43
10115 Berlin
Office phone: +49 (0)30 2093 8764
Email: heinrich.mallison< at >gmail.com
_____________________________________
Fere libenter homines id quod volunt credunt.
Gaius Julius Caesar


On Sat, May 26, 2012 at 12:16 AM,  <GSP1954< at >aol.com> wrote:

Re: Microraptor hanqingi, new species from China.

2012-05-25T22:16:52

This discussion is as obsolete as it is going on, and on, and on. In all 
seriousness, I am in the process of developing a data set that when published 
will go a long, long, long way to settle a lot of the debate over what was 
and was not arboreal when it comes to dino-birds and basal birds. And no two 
ways about it, sinornithosaurs were extremely arboreal with very little 
ground time. And I have way cool info on Archaeopteryx that will cause all to 
gasp in wonder and amazement (I was rather startled). All you have to do is 
wait a year or two until I get around the finishing up data collection and get 
around to getting it published. So I suggest putting off these discussions 
until that happy day. Actually I beg of you. 

Speculation is futile, 

GSPaul</HTML>

FW: Microraptor hanqingi, new species from China.

Jason Brougham — 2012-05-25T21:38:16

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.

Ins

FW: Microraptor hanqingi, new species from China.

Jason Brougham — 2012-05-25T21:37:29

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"< at >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 th

Re: Microraptor hanqingi, new species from China.

Habib, Michael — 2012-05-25T20:36:38

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:


Michael Habib
Assistant Professor of Biology
Chatham University
Woodland Road, Pittsburgh PA  15232
Buhl Hall, Room 226A
biologyinmotion< at >gmail.com
(443) 280-0181

Re: Microraptor hanqingi, new species from China.

Habib, Michael — 2012-05-25T20:34:03

On May 25, 2012, at 3:53 PM, Don Ohmes wrote:


If you expect no differences in anatomy, then what are we looking for?  Do you propose differences in taphonomy or paleoenvironment?  We only have a handful of things that can be used to test predictions.  The roosting in trees model seems reasonable, but it is nothing more than a reasonable speculation unless you have something we can test.  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.  If your assertion is, instead, that we'd see no difference in the fossil record between a case a fully "terrestrial" origin and a "terrestrial + tree roosting" origin, then I'm not sure what is being argued.


So, then is your argument simply that there might have been some arboreal activity involved that we will never see in the fossil record?  If so, I'm inclined to agree - but then I also don't know what all the arguing is about.

Re: Microraptor hanqingi, new species from China.

Don Ohmes — 2012-05-25T19:53:28


The statement made was that (paraphrasing) 'theropods w/ vertical 
climbing capacity must need special equipment to sit in trees' -- 
someone please support that idea!

It is critical to the argument that creatures evolving flight in 
tree-down mode would show "arboreal adaptations" that need comparing...

Do I need to point out (yet again) that if there is no *need* for 
special equipment, then there is no selective path to adaptation -- and 
thus "comparing [...] adaptations" is not useful in this context?

It is a simple matter of evolutionary theory, mechanical possibilities 
and uniformintarian assumptions -- either it reasonable to assume that a 
sleeping theropod would a) fall out of a tree and b) then be removed 
from the gene pool -- or it is a completely indefensible crock.

If it is a crock, then the argument that tree-down is falsified for 
(e.g.) Archeopteryx, due to it's toe angles, is also a crock.


"My model" falsifies the idea that an animal evolving flight in 
tree-down gliding-first mod

Re: Microraptor hanqingi, new species from China.

Augusto Haro — 2012-05-25T19:09:45

2012/5/25 Habib, Michael <MHabib< at >chatham.edu>


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
(contrasting with merely ornamental or egg-protecting hypotheses, which I
cannot refute, BTW), and reading in some aged book that Archaepteryx could
not start gliding from the floor even if it was acquiring velocity by
running (I do not remember the physical argument for such an assertion, and
would like to know if it is true), so being forced to start from above.
2 - Although now obsolete, Fedduccia's (1993) argument on ungual curvature.

Other alternative scenario for a gliding origin of flight would be, as
previously mentioned by someone, very "rugous" or irregular terrain, which
would permit economy of transport for gliders and by the

Re: Microraptor hanqingi, new species from China.

Habib, Michael — 2012-05-25T18:18:46

Wouldn't the evidence in this case just be comparative studies of arboreal adaptations?  Not sure what else it could be.  We don't have any non-avian theropods handy to throw into a tree (wouldn't that be fun, though, if we did?  Theropod chucking.  New sport).

Like Scott, I find your model of arboreal refugia quite reasonable.  I'm wondering, though, what testable predictions your model would make compared to, for example, a model that posits entirely terrestrial habits for paravians.  I think the roosting/resting concept has serious merit, but I'm not sure how to go about demonstrating it has serious merit more formally (thought experiments and scenario building are fun, but not terribly useful).

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.

--Mike


Michael Habib
Assistant Professor of Biology
Chatham Univer

Re: Microraptor hanqingi, new species from China.

Don Ohmes — 2012-05-25T17:26:15

Like beach balls, plastic flamingos, and goats.

On 5/24/2012 12:44 AM, Tim Williams wrote:

 > But if you're a theropod, and you want to spend a large
 > part of your life sitting on boughs or branches, you need to have a
 > way of holding on.

Evidence, please...

In particular, evidence of the need for special equipment, beyond the 
standard small theropod package.

RE: Microraptor hanqingi, new species from China.

Anthony Docimo — 2012-05-25T16:55:26



----------------------------------------


 So we can understand how something works, by watching something which is near-enough to the ancient organism's methods.



 Fine.  Then what behaviors should we use and reconstruct?


So...we're back to looking for modern bird anatomy in proto- and non-birds?


That's why some of us mention non-bird analogies.