Re: thanks for tracks & a question

["RAY D STANFORD" <STARSONG@prodigy.net>]

Hello Jack and List,

    QUESTION:  What is the orientation of the hind feet in these tracks?

    ANSWER:  In studying the Maryland Sauropod tracks, we have no direct
evidence to answer this question.  Why?  Here, we have no large areas of
exposed track-way substrate easily accessible for examination.  (I have only
recovered a few trackways made by smaller dinosaur species.)

    Urbanization (its paving, concrete, landscaping, and buildings) is a
major factor in this situation, as are the lay of the land and the fact that
un-broken substrates of the types from which the usually-individual tracks
derive only show up edge-on, well below the surfaces, in stream banks,
ravines, or man-made excavations and stream modifications.

    The whole tracks (e.g.,the fourteen Sauropod manus impressions) I find
are usually preserved only because the sand or silt grains around the
impressions are closer together (pushed closer by force of the animal's
foot) than more-distant grains, so that when, for example, an earth-moving
machine has impacted the area with a blade or 'bucket', the fractures tend
to occur in the less-compacted area, thus often leaving the imprints
serendipitously  whole.

    In such situations, small to medium-sized tracks are naturally 'favored'
for preservation, but among the Sauropod pes (foot as contrasts with manus
or hand) impressions, one whole, natural cast of a right pes measuring
66 cm (26 inches) across has been recovered.   The largest yet found in
Maryland, this natural cast (13 cm, or just over 5 inches, thick) shows that
the animal's claw pattern (and, deductively, probably the toes) bent sharply
to the outside.

   This bend is not so extreme as that shown in track photos in chapter 34
(pages 313 - 332) of the book, DINOSAUR TRACKS AND TRACES (See complete
reference in my post of last evening.).  That Chapter is entitled: The Briar
Site: A New Sauropod Dinosaur Tracksite in Lower Cretaceous Beds of
Arkansas, USA, by Jeffrey G. Pittman and David G. Gillette.

    The bend of the claw impressions in the Maryland natural cast seems,
however, slightly more extreme than those we see in typical Paluxy river-bed
pes tracks.  See the Brontopodus birdi chapter (pages 371 - 394) in the same
book.

    One might deduce that maker of the 66 cm-wide Maryland track was maybe
half-grown, if it is presumed that the Maryland, Arkansas, and Texas
tracks were made by the same type animal.  The Maryland Sauropod tracks
(front and back) have a very striking similarity to, especially, the Paluxy
tracks, as anyone who has come here and examined them first-hand will tell
you.

    So, in responding to your initial question, Jack, due to the
non-availability of probably extant Maryland trackways, per se, I can only
answer the question deductively and, unfortunately, not by direct
observation:  Because in sauropod foot prints there appears to be a
relationship of toe-claw bend to the degree by which a Sauropod pes has its
foot's long-axis oriented anterio-laterally,  it seems (based on observed
pes-toe bends) that Maryland sauropods' feet were probably carried
oppositely of what we call 'pigeon-toed'.

    Roland Bird (who was evidently the first person to realize that the
biggest Paluxy tracks were produced by Sauropods) is said to have speculated
that sometimes it seems a Sauropod could alter claw angulation in response
to specific needs.

    Now, to your other  QUESTION:  How close to the mid-line are the hind
feet tracks?

    ANSWER:  Again, because we have accessed no Sauropod trackways here in
Maryland, no definite answer is possible.  One could speculate that, because
of the very close resemblance of the Maryland tracks to, especially, those
in the Paluxy river bed, then the back-foot lateral displacement from a
central line was probably (or possibly) similar, i.e., 'wide gauge'.  In the
Paluxy trackways, the separation along that central line was about one
manus-width apart.

    We owe the term, 'wide-gauge' to our list member Dr. James O. Farlow,
who coined this handy term out of what Martin Lockley calls Jim's being a
"railway enthusiast".  Likewise, Jim has called the Sauropod trackways such
as those in Colorado (Jurassic) 'narrow gauge', wherein the back feet
essentially touch the central line of progression,   The term certainly
seems to have caught on, and, after all, it saves a lot of words.

    Although I'm not sure how far a certain idea's consistency-to-fact has
been tested against the trackway record over the long period when Sauropods
existed, a generalization has been suggested by some researchers, that
describes the gauge of Sauropod tracks as having widened across time.  [Hey,
did they have fast food back then? ;)]

    Interestingly, one examines the Sauropod trackways already known, we
see that even the most 'wide-gauge' trackways (presumably all from the
Cretaceous) inform us that Sauropods were (considering their length) rather
svelt, slim-bodied animals.  Our most observant artists, such as Greg Paul
and others on this list, are now more accurately portraying sauropods as the
sleek, rather slim-bodied animals they were.

    Perhaps anyone using Sauropod models in volumetric displacement studies
to facilitate calculations of body weight, had better use the newest
slim-bodied versions, to avoid seriously over-estimating Sauropod tonnage.

    Hope this helps someone's knowledge of Sauropods and of the difficulties
and limitations one confronts in the study of their ichnites here in
Maryland.

    Ray Stanford



From: jconrad@lib.drury.edu <jconrad@lib.drury.edu>

...I also have two quick questions:

What is the orientation of the hind feet in these tracks?  That is, do the
toes face straight ahead, inward ("pigeontoed"), or slightly outward?

and

How close to midline are the hind feet tracks?

Thanks for your time.  I love theropods, but this is a refreshing topic.

Jack