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Re: Addendum to UPDATE (Maryland tracks)
Hello Dwight and List,
Dwight, your question is an important one:
QUESTION: Is there evidence for a digit 1CLAW in the Sauropod manus
ANSWER: In FOUR of the fourteen (I just counted them.) Sauropod manus
tracks from the Cretaceous (possibly Aptian -- Tom Lipka is working on
dating) of Maryland, one sees impressions that might be interpreted as
evidence of a rather small claw associated with digit 1. These marks could
not have been made by a really big claw, but I get the impression (It would
be nice to have more examples to study.) that its angle of orientation might
have been somewhat variable: slight, within horizontal plane of the manus,
but maybe more-so, within a vertical direction as well. Certainly this
(if that is what the referenced depressions represent) would not have made
much of a defensive weapon, so maybe it had some other function.
The relative size of the digit 1 claw might be similar to the quite
small one carried by Brachiosaurus brancai, as shown in a skeletal
illustration in Figure 42.8 -G, on page 379 of the book DINOSAUR TRACKS AND
TRACES (pages 371 through 393, being a chapter entitled Brontopodus birdi,
Lower Cretaceous Sauropod Footprints from the U.S. Gulf Coastal Plain, by
Farlow, Pittman, and Hawthorne), Cambridge University Press, 1989.
Greg Paul's illustration, published in at least two different books, of
adult Astrodon johnstoni with young is probably quite accurate, if one
reasonably accepts the Maryland imprints we have found as having been made
by that animal.
In one of the best Sauropod manus imprints from Maryland, we see a small
but very distinct, 'trench' ("V"-shaped in cross section) that might have
been produced by a digit 1 claw scraping inward (posterio-medially) as the
manus was lifted from the substrate.
I think we can be reasonably sure of the most obvious of the Maryland
Sauropod manus features, simple because they are so precisely replicated in
a good variety of substrate types, and across a nice range of sizes.
The largest Sauropod manus imprint yet found here (I am aware only of
those in my collection.) is 35 cm across at its broadest expanse. The
smallest is only 4.5 cm across! Yet, these two and those in between (in
size) are consistently and impressively similar.
Thanks for that good question, Dwight. I know 'trackers' other that
myself have been looking for digit 1 manus claw impressions, but an not sure
whether I've read of similar impressions being found elsewhere. Anybody
have the answer to that?
From: Stewart, Dwight <Dwight.Stewart@VLSI.com>
To: 'STARSONG@prodigy.net' <STARSONG@prodigy.net>; Dino mailing list
Date: Monday, February 22, 1999 8:13 PM
Subject: RE: Addendum to UPDATE (Maryland tracks)
Ray (or anyone who knows, for that matter), is there evidence for
claws in these prints?
Particularly, I am thinking about evidence of a claw on the first