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Baby dinosaur tracks from Morrison
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.
Also:
Paper No. 142-6: FROM THE TOMB OF THE FIRST STEGOSAURUS:
A PRELIMINARY REPORT ON A STEGOSAUR-RICH TRACK ASSEMBLAGE
FROM LAKES' QUARRY 5, MORRISON FORMATION OF MORRISON,
COLORADO
http://gsa.confex.com/gsa/2010AM/finalprogram/abstract_182
427.htm
FROM THE TOMB OF THE FIRST STEGOSAURUS: A PRELIMINARY
REPORT ON A STEGOSAUR-RICH TRACK ASSEMBLAGE FROM LAKES'
QUARRY 5, MORRISON FORMATION OF MORRISON, COLORADO
MOSSBRUCKER, Matthew T., Morrison Natural History Museum,
501 Colorado Highway 8, Post Office Box 564, Morrison, CO
80465, director@mnhm.org and BAKKER, Robert T., Houston
Museum of Natural Science / Morrison Natural History
Museum, 501 Colorado Highway 8, PO Box 564, Morrison, CO
80465
Arthur Lakes removed giant Late Jurassic dinosaurs from
his Quarry 5 sandstone, excavated in 1877-78 at Morrison,
Colorado. This quarry is famous for producing the type
specimen for the genus Stegosaurus (S. armatus, Yale
Peabody Museum specimen 1850). Neither Lakes nor
subsequent investigators reported footprints from the
Quarry 5 sandstone. We have examined bedding surfaces on
the talus blocks of the Quarry 5 left along the roadway
at Morrison. The blocks preserved an ichnofauna unusually
rich in stegosaurs, adult and juvenile, plus sauropods,
juvenile and adult, theropods, ornithopods, lepidosaurs,
and possible badger-sized mammal.
During the 1930?s the Alameda road was built across the
hogback ridge where the Quarry 5 sandstone outcropped.
Road-building activity displaced bone-bearing boulders
which then were parbuckeled onto the shoulder of the
road. In 2005, a roadside safety girder was scheduled to
be installed on the shoulder of Alameda Parkway, and
Morrison Museum staff collected and moved to the museum
in January of 2005.
Locating tracks was done in two ways: strong, oblique
lighting and high resolution latex peels. This process
revealed diminutive tracks, including three tiny theropod
tracks only 16 millimeters long (measured from the
anterior extent of the third digit to the posteriormost
extent of the track). Track identification began with an
analysis of manual and pedal skeletons when possible, in
conjunction with a review of published inchnotaxa.
The most common track morphotype from Quarry 5
ichnofacies range are wider medio-laterally than deep
anterio-posteriorly, tridactyl with blunt digits ending
in squared, hoof-like claws. Combined, these characters
point to the pes of a single genus: Stegosaurus.
Stegosaurus-morphotype tracks range in size from
hatchling (estimated body mass 3kg) to adult animals
(estimated body mass 6-8 tons). One talus block
demonstrates adult stegosaur pedal track partially
crushing a juvenile Stegosaurus-morphotype track,
implying social behavior amongst juvenile and adult
stegosaurs.
As with the bone sample from Quarry 5, the ichnofauna
suggests an atypical Morrison Formation ichnofauna,
enriched in stegosaurs. The Quarry 5 ichnofauna also
provides insight into habitat preference and social
behavior amongst stegosaurs.