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Re: Running, bipedal? Re: Baby dinosaur tracks from Morrison



The simple answer is probably that the pes is partially or completely
overstepping the manus. The adult sauropod tracks that I have worked
on appear to be one big oval with claws sometimes sticking out the
front. Conceivably the babies do not leave claw impressions. Peabody
(1959) looked at degrees of coupling (ie the distance relationship
between manus and pes prints in paired prints) in salamanders, besides
being an interesting paper it shows that with long legs and a short
body (sound anything like a "baby")  the 1st order prints can be quite
close together (the fun is with short legs and a long body where the
pes will step on the manus impression from 3 steps ago (3rd order
coupling)). Heck even "common" animals like horses do a pretty good
job of obliterating their manus prints with their pes.

Then again maybe they are just circular depressions in the rock. We
will have to wait till a trackway is published.
    -Tyler Shaw

On Wed, Nov 3, 2010 at 9:46 AM, Heinrich Mallison
<heinrich.mallison@googlemail.com> wrote:
> "radially" (pear-shaped pressure lines) is only true over time, not
> for an impact.
>
> There's a very nice Milan and someone paper on that, it was cited on
> the list within the last two days, IIRC.
>
> :)
> H
>
> On Wed, Nov 3, 2010 at 4:35 PM, Saint Abyssal <saint_abyssal@yahoo.com> wrote:
>> Aren't underprints physically impossible? There was a 2001 paper in the 
>> Mesozoic Vertebrate Life collection which argued that the force of the 
>> trackmakers weight is exerted radially through the sediment instead of 
>> straight down, so although there's some compression under the track, the 
>> force fades so rapidly that the idea of a traditional "underprint" or "ghost 
>> print" isn't feasible.
>>
>> ~ Abyssal
>>
>> --- On Wed, 11/3/10, Thomas R. Holtz, Jr. <tholtz@umd.edu> wrote:
>>
>>> From: Thomas R. Holtz, Jr. <tholtz@umd.edu>
>>> Subject: RE: Running, bipedal? Re: Baby dinosaur tracks from Morrison
>>> To: rtravsky@uwyo.edu, dinosaur@usc.edu
>>> Date: Wednesday, November 3, 2010, 3:13 PM
>>> > From: owner-DINOSAUR@usc.edu
>>> [mailto:owner-DINOSAUR@usc.edu]
>>>
>>> > On Behalf Of Richard W. Travsky
>>> >
>>> > On Mon, 1 Nov 2010, bh480@scn.org
>>> wrote:
>>> >
>>> > > From: Ben Creisler
>>> > > bh480@scn.org
>>> > >
>>> > > In case this news story has not been mentioned
>>> yet:
>>> > >
>>> > > http://www.genengnews.com/industry-updates/morrison-
>>> > > natural-history-museum-discovers-baby-sauropod-
>>> > > tracks/98965127/
>>> > >
>>> > > Mentions tracks from baby apatosaurs with
>>> possible evidence
>>> > that baby
>>> > > sauropods sometimes ran on hindlimbs only.
>>> >
>>> > Link not found. However, a similar (might even be the
>>> same)
>>> > article is here:
>>> >
>>> > http://www.geosociety.org/news/pr/10-63.htm
>>> > Morrison Natural History Museum Discovers Baby
>>> Sauropod
>>> > Tracks Tracks of a Running Bipedal Baby Brontosaur?
>>> >
>>>
>>> One VERY important issue (for which we will have to Wait
>>> For The Paper): are the pedal prints tracks, or are they
>>> undertracks? It
>>> might well be that the little dino is running
>>> quadrupedally, but we are sampling layers under the actual
>>> muddy surface, which only
>>> the pedal impression reached.
>>>
>>> As has been shown by Manning (among many others), knowing
>>> if you are dealing with real tracks or undertracks can make
>>> a LOT of
>>> difference in interpretation.
>>>
>>> Thomas R. Holtz, Jr.
>>> Email: tholtz@umd.edu
>>> Phone: 301-405-4084
>>> Office: Centreville 1216
>>>
>>> Senior Lecturer, Vertebrate Paleontology
>>> Dept. of Geology, University of Maryland
>>> http://www.geol.umd.edu/~tholtz/
>>> Fax: 301-314-9661
>>>
>>> Faculty Director, Science & Global Change Program,
>>> College Park Scholars
>>> http://www.geol.umd.edu/sgc
>>> Fax: 301-314-9843
>>>
>>> Mailing Address:    Thomas R. Holtz, Jr.
>>>
>>> Department of Geology
>>>
>>> Building 237, Room 1117
>>>
>>> University of Maryland
>>>
>>> College Park, MD 20742 USA
>>>
>>>
>>
>>
>>
>>
>
>