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| Augustana In Antarctica
Augustana Professor Makes Fossil Finds On Frozen Continent |
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Augustana professor Dr. William R. Hammer is a veteran of Antarctic science.
Having traveled to the frozen continent 5 times for research, Hammer has
become well known for his fossil discoveries. During his fourth expedition,
(1990-91 field season), Hammer and his field team, which also included
Augustana graduate William J. Hickerson, made a major find. At an elevation
of approximately 14,000 feet on Mt. Kirkpatrick not far from the South
Pole, the team excavated Antarctica's first dinosaur along with bones from
several other animals.
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The vertebrate
assemblage collected during the 1990-1991 field season from Mt. Kirkpatrick
in the Beardmore Glacier region of the Central Transantarctic Mountains
includes 120-140 bones, and 16 teeth representing at least six different taxa. The specimens are from the
Hanson Formation and include the
partial skull and numerous postcranial elements from a crested theropod
dinosaur, Cryolophosaurus ellioti.
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The name means "frozen crested reptile" and Cryolophosaurus
represents the only theropod to be found in Antarctica. The characteristic
feature of the dinosaur is the large crest
on the top of the skull, above the eyes. The nasal bones extend toward
the back of the skull as ridges, and then join with the lacrimal bones
to form a grooved crest which extends perpendicularly from the skull.
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Cryolophosaurus ellioti has some features in common with North American
therapods of the Jurassic such as Allosaurus.
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In addition to the numerous bones which belong to a single individual
of Cryolophosaurus there were bones from several other animals found
at the same sight. Animals such as a primitive pterosaur (flying reptile),
a tritylodont, and most significantly a plateosaurid prosauropod.
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The prosauropod is represented by a partial foot and the distal end of
a femur. The animal's foot structure and size are nearly identical to two
large plateosaurid prosauropods known from Germany and China. Therefore
the Antarctic prosauropod is closely related to these forms.
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An age
of Early Jurassic has been suggested for the Hanson Formation. Several factors were used to arrive
at this age estimation. A Dicroidium flora found approximately 300 meters below the bone bed indicates a Late Triassic age for the Lower Falla
Formation that lies beneath the Hanson.
Prosauropods are known from all other continents and are restricted to
the Late Triassic to Early Jurassic. Tritylodonts similar to the Antarctic
form are known from the Early to middle Jurassic. Thus, the
overlapping ranges of the prosauropods and tritylodonts indicate an
Early Jurassic age for them.
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In addition to the fauna which included the dinosaur, Dr. Hammer has collected
numerous Triassic age amphibian and mammal-like reptile specimens during his expeditions.
Hammer is currently making plans for a seventh expedition to the
Antarctic. He and his team hope to revisit the area where the
dinosaur fauna was discovered. |
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