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ZEPHYROSAURUS -- Does anyone know of data...?
I am about to ask a question for which there may be no current answer,
but in case the information might be out there somewhere (albeit unknown to
me), I will go ahead and describe what I'd like to learn, and why:
Here in Maryland over the past several years, I have found three pes
imprints that, although recorded in substrates of three different types,
show virtually identical 'four-on-the-floor' impressions. (That is, digits
1,2,3, & 4 of the pes show clearly in each imprint.)
Each of the three pes imprints must have been made by feet of virtually
identical size, and all four toes of each imprint display an odd (compared
to all other Theropod and Orinthopod pes impressions I have seen) outline as
seen from above. That is, each digit outline diverges surprisingly from a
noticeably narrow proximal width, continually expanding until the ungual
phalanx. There, a long, essentially triangular (as viewed from above)
ungual impression which subtends an (approximately) 54 degree arc, as
measured in digit 3, from that digit's distal end (tip) of the ungual
impression, back toward the proximal.
Fortunately, one of the three strange pes impressions is accompanied by
a equally clear, 'FIVE on the floor' MANUS impression, as though a normally
bi-pedal dinosaur had stopped, paused, or bent over to drink (maybe),
placing at least one of its mani on the surface.
That manus impression coincides precisely with the pattern one sees in
scientific illustrations of the manus bone structure of Hypsilophodon foxii,
if one imagines it fleshed-out. Yet, when one compares the ratio (to give
an example) of the length of Hypsilophodon's third pedal digit to that of
its third manus digit 3 (I got a tentative ratio of 1.65, but this should
probably be refined), one quickly notices that the track-maker who left the
pes-manus set of impressions I am studying, had a substantially smaller
manus as compared to pes. That ratio for the mystery tracker, derived as
just described for Hypsilophodon, comes out 2.7. Therefore, we see that
Maryland's late Early-Cretaceous track-maker, while having a manus and pes
of essentially identical form to those of Hypsilophodon, had a substantially
smaller manus, as compared to its pes size, than did H. foxii.
It may help in visualizing the pes-manus set, to mention that the pes is
9 cm across, accompanied by a manus of about 3.5 cm across.
When Bob Bakker examined the prints described earlier, he speculated
that the track maker may have been Zephyrosaurus. I know that Zephyrosaurus
schaffi had been described by Sues (1980) from partial scull and some
postcranial elements, but because I have read that subsequent Zyphyrosaurus
material has been found (from another location), my question is as follows:
DOES ANYONE OF YOU 'OUT THERE' KNOW WHETHER SUFFICIENT ZYPHYROSAURUS
MATERIAL HAS NOW BEEN RECOVERED FOR US TO DETERMINE WHETHER ZEPHYROSAURUS
HAD A SMALLER MANUS, AS COMPARED TO ITS PES, THAN DID HYPSILOPHODON?
The initial Zyphyrosaurus material was recovered from the Cloverly
Formation, Wolf Creek Canyon, Carbon County, Montana. It is interesting
that the Cloverly coincides rather closely (temporally) with our Potomac
Group here in Maryland (from which the tracks derive). Because we now know
that at least some of our dinosaurs from Maryland were evidently the same as
those from the Cloverly, I begin to think that Bob Bakker may have been
'right on' in suggesting that the Maryland trackmaker was Zephyrosaurus.
If anyone can suggest a more fitting solution as to the possible
identity of our Maryland mystery trackmaker, I would welcome it, but with
surprise. I can tell you in advance of any proposals that the trackmaker
does NOT seem to have been a (sub-adult) Tenontosaurus. (For one thing, the
manus is wrong for that.)
O.K., ladies and gentlemen of the list, have at it! I'm not looking
for criticism of my clearly inadequate descriptive ability, but for the
positive reward of further insight into the possible trackmaker.
THANKS for any help you can provide.
P.S.: Now let's not have a stampede here! :)