Four dinosaurs discovered in Montana, including a possible rare ostrich-
mimic Anzu
Fieldwork pieces together life at the end of `Dinosaur Era'

Date:
September 21, 2021
Source:
University of Washington
Summary:
A team of paleontologists excavated four dinosaurs in northeastern
Montana this summer. The four dinosaur fossils are: the ilium -- or
hip bones -- of an ostrich-sized theropod, the group of meat-eating,
two- legged dinosaurs that includes Tyrannosaurus rex and raptors;
the hips and legs of a duck-billed dinosaur; a pelvis, toe claw and
limbs from another theropod that could be a rare ostrich-mimic Anzu,
or possibly a new species; and a Triceratops specimen consisting
of its skull and other fossilized bones.



FULL STORY ==========================================================================
A team of paleontologists from the University of Washington and its
Burke Museum of Natural History and Culture excavated four dinosaurs in northeastern Montana this summer. All fossils will be brought back to
the Burke Museum where the public can watch paleontologists remove the surrounding rock in the fossil preparation laboratory.


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The four dinosaur fossils are: the ilium -- or hip bones -- of an
ostrich-sized theropod, the group of meat-eating, two-legged dinosaurs
that includes Tyrannosaurus rex and raptors; the hips and legs of a
duck-billed dinosaur; a pelvis, toe claw and limbs from another theropod
that could be a rare ostrich- mimic Anzu, or possibly a new species;
and a Triceratops specimen consisting of its skull and other fossilized
bones. Three of the four dinosaurs were all found in close proximity on
Bureau of Land Management land that is currently leased to a rancher.

In July 2021, a team of volunteers, paleontology staff, K-12 educators
who were part of the DIG Field School program and students from UW and
other universities worked together to excavate these dinosaurs. The
fossils were found in the Hell Creek Formation, a geologic formation
that dates from the latest portion of Cretaceous Period, 66 to 68
million years ago. Typical paleontological digs involve excavating one
known fossil. However, the Hell Creek Project is an ongoing research collaboration of paleontologists from around the world studying life right before, during and after the K-Pg mass extinction event that killed off
all dinosaurs except birds. The Hell Creek Project is unique in that it
is sampling all plant and animal life found throughout the rock formation
in an unbiased manner.

"Each fossil that we collect helps us sharpen our views of the last
dinosaur- dominated ecosystems and the first mammal-dominated ecosystems,"
said Gregory Wilson Mantilla, a UW professor of biology and curator
of vertebrate paleontology at the Burke Museum. "With these, we can
better understand the processes involved in the loss and origination of biodiversity and the fragility, collapse and assembly of ecosystems."
All of the dinosaurs except the Triceratopswill be prepared in the
Burke Museum's fossil preparation laboratory this fall and winter. The Triceratopsfossil remains on the site because the dig team continued
to find more and more bones while excavating and needs an additional
field season to excavate any further bones that may be connected to
the surrounding rock. The team plans to finish excavation in the summer
of 2022.

Called the "Flyby Trike" in honor of the rancher who first identified
the dinosaur while he was flying his airplane over his ranch, the team
has uncovered this dinosaur's frill, horn bones, individual rib bones,
lower jaw, teeth and the occipital condyle bone -- nicknamed the "trailer hitch," which is the ball on the back of the skull that connects to the
neck vertebrae. The team estimates approximately 30% of this individual's
skull bones have been found to date, with more potential bones to be
excavated next year.

The Flyby Trike was found in hardened mud, with the bones scattered
on top of each other in ways that are different from the way the bones
would be laid out in a living animal. These clues indicate the dinosaur
likely died on a flood plain and then got mixed together after its death
by being moved around by a flood or river system, or possibly moved
around by a scavenger like a T. rex, before fossilizing. In addition,
the Flyby Trike is one of the last Triceratops living before the K-Pg
mass extinction. Burke paleontologists estimate it lived less than
300,000 years before the event.

"Previous to this year's excavations, a portion of the Flyby Trike frill
and a brow horn were collected and subsequently prepared by volunteer preparators in the fossil preparation lab. The frill was collected in many pieces and puzzled together fantastically by volunteers. Upon puzzling the frill portion together, it was discovered that the specimen is likely an
older 'grandparent' Triceratops," said Kelsie Abrams, the Burke Museum's paleontology preparation laboratory manager who also participated in
this summer's field work. "The triangular bones along the frill, called
'epi occipitals,' are completely fused and almost unrecognizable on the specimen, as compared to the sharp, noticeable triangular shape seen
in younger individuals. In addition, the brow horn curves downwards as
opposed to upwards, and this feature has been reported to be seen in
older animals as well." Amber and seed pods were also found with the
Flyby Trike. These finds allow paleobotanists to determine what plants
were living alongside Triceratops, what the dinosaurs may have eaten,
and what the overall ecosystem was like in Hell Creek leading up to the
mass extinction event.

"Plant fossil remains from this time period are crucial for our
understanding of the wider ecosystem. Not only can plant material
tell us what these dinosaurs were perhaps eating, but plants can more
broadly tell us what their environment looked like," said Paige Wilson,
a UW graduate student in Earth and space sciences. "Plants are the
base of the food chain and a crucial part of the fossil record. It's
exciting to see this new material found so close to vertebrate fossils!"
Museum visitors can now see paleontologists remove rock from the first of
the four dinosaurs -- the theropod hips -- in the Burke's paleontology preparation laboratory. Additional fossils will be prepared in the
upcoming weeks. All four dinosaurs will be held in trust for the public
on behalf of the Bureau of Land Management and become a part of the
Burke Museum's collections.

========================================================================== Story Source: Materials provided by University_of_Washington. Original
written by Andrea Godinez. Note: Content may be edited for style and
length.


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Link to news story: https://www.sciencedaily.com/releases/2021/09/210921172653.htm

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