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Re: SIMILAR BIRD TRACKS 70 MILLION YEARS APART



Ray,
From my perspective, I would consider it extremely unlikely that your E. Cretaceous and Eocene tracks were made by members of the same genus, and not even very probable that they were in the same family. Perhaps at ordinal level (both possibly members of Charadriiformes, Ciconiiformes, or whatever), there could be a relationship, but even at that taxonomic level, convergent similarity could be a problem.
And even if these birds were somewhat related, I doubt that this would indicate a surviving population of any birds in eastern North America. The surviving birds were probably much farther away, and that area would have been repopulated with birds during the Paleocene.
Not much more than 2 cents worth, I'm afraid, but I wouldn't read too much into the similarities between the Cretaceous and Eocene tracks.
-----Cheers, Ken
******************************************** 
From: "Ray Stanford" <dinotracker@earthlink.net>
Reply-To: "Ray Stanford" <dinotracker@earthlink.net>
To: "Dinosaur Mailing List" <dinosaur@usc.edu>
Subject: SIMILAR BIRD TRACKS 70 MILLION YEARS APART
Date: Wed, 19 Sep 2001 18:23:04 -0400

Recovered from the Early Cretaceous of Maryland: three virtually
identical bird tracks (two successive, and a third one, unassociated, on a
different type of substrate) each with the same 132 degree angle of
divarication (digits II through IV), and with a reversed digit I at roughly
104 degrees from digit II. Pes width is 3.8 cm. Digit impressions are very
narrow.

What really amazes me about these three tracks, however, is that they
are identical in size and angulations to a very typical type of Green River
Formation track from roughly 70 million years later! :o If, for sake of
discussion, one considers that these identical footprints 70 million years
apart were made by very similar birds, might one realistically consider this
in terms of possibly a remarkable survival of an evolutional line of closely
related species, across the K/T boundary?

    Worthy of a paper, or not?

So, does anyone out there know whether any Early Cretaceous bird, known
from skeletal materials, had such a foot? Should such a foot, so early, be
surprising? These look like the tracks of a shore bird to me, but I'm no
ornithologist.

    Thanks in advance for any informed comments and help.

    Ray Stanford

"You know my method.  It is founded upon the observance of trifles." --
Sherlock Holmes in The Boscombe Valley Mystery



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