| News
Release from Ohio University:
Brain structure provides the key to
unraveling the function of bizarre dinosaur crests
High-tech imaging reveals inner structure of duck-billed
dinosaur skulls
ATHENS, Ohio (Oct. 9, 2008) — Paleontologists have long
debated the function of the strange, bony crests on the
heads of the duck-billed dinosaurs known as lambeosaurs.
The structures contain incredibly long, convoluted nasal
passages that loop up over the tops of their skulls.
Scientists at the University of Toronto, Ohio University
and Montana State University now have used CT-scanning
to look inside these mysterious crests and reconstruct
the brains and nasal cavities of four different
lambeosaur species. At the annual meeting of the Society
for Vertebrate Paleontology in Cleveland, Ohio, on Oct.
16, the team will present new study findings that
suggest the crests were used for communication.
“The shape of the brain can tell us a lot about what
senses were important in a dinosaur’s everyday life, and
give insight into the function of the crests,” said
study lead author David Evans, a paleontologist at the
Royal Ontario Museum and the University of Toronto.
Some paleontologists have suggested that the crests
heightened the sense of smell by increasing the surface
area of the sensory tissue. Others have argued that they
regulated temperature, and still others have speculated
that the crests acted as sound resonators for
communication.
“It’s difficult to infer the function of structures in
an extinct dinosaur when there is so little resemblance
to any living animal,” said Jack Horner, a member of the
team and paleontologist at Montana State University.
By
using and analyzing CT scans, conducted by Lawrence
Witmer and Ryan Ridgely of Ohio University’s College of
Osteopathic Medicine, the scientists were able to
circumvent the problems of fossilization.
“Even though the soft tissues are not preserved in the
fossils, the shape of the bones that encase the brain
and nasal passages are,” said Evans. “From there, the
anatomy of these missing soft parts is easily
interpreted.”
The CT scan results revealed a mismatch between the
external shape of the crest (which no doubt functioned
as a visual display) and the internal shape of the nasal
passages in closely related species, suggesting a
special function for the nasal cavity. The portion of
the brain responsible for the sense of smell was
relatively small and primitive, indicating that the
crest did not evolve to improve that sense.
Computer models done by other researchers suggest that
the crests could have been used to make low, eerie
bellowing calls that could have been used in
communication, perhaps to call for mates or warn others
of predators. The CT scans documented a delicate inner
ear that confirms that the dinosaurs could hear the
low-frequency calls produced by the crest.
“We were surprised to see just how large the centers of
the brain associated with higher cognitive functions
were,” said Witmer,
Chang
Professor of Paleontology in Ohio University’s College
of Osteopathic Medicine.
“We suspected that the crested duck-billed dinosaurs
used both vocal and visual displays, but now we see that
they had the brain power and hearing to pull off these
behaviors.”
When all the available information is put together,
including the digital brain and ear casts, the
evolutionary relationships of the species, and the
growth pattern of the crest and its high degree of
variability in different co-existing species, it
supports the idea that the elaborate nasal cavity was
likely used to produce sounds for communication. This
study demonstrates the power of using an integrated
approach combining 3D imaging, growth studies, and
phylogenetic sampling to test ideas about the function
and evolution of unusual structures in extinct animals.
The research was funded by the National Science and
Engineering Research Council of Canada and the National
Science Foundation.
This study also will be published in part in an upcoming
issue of the journal The Anatomical Record.
Contact: David Evans can be contacted at:
davide@rom.on.ca,
Ph:
416-586-5753; Lawrence Witmer can be contacted at
witmerL@ohio.edu, Ph: 740-593-9489.
Note to
media: High-resolution images and animations of the
lambeosaurs can be viewed and downloaded here:
Media/SVP_dinosaur/SVP_dinosaur_media.htm
Case-sensitive login - username: svp-ou, password:
Dino12
|
| News
Release from the Society of Vertebrate Paleontology:
Talk presented at the Annual
Meeting of the Society of Vertebrate Paleontology in
Cleveland, Ohio, on Thursday, October 16th at 8:30 AM.
Brain structure provides the key to
unraveling the function of bizarre dinosaur crests.
New study uses high-tech imaging to explore inner
structure of dinosaur skulls
David C. Evans. Dept. of Natural
History, Royal Ontario Museum, Toronto, Ontario, Canada.
(Ph: 416-586-5753)
Lawrence M. Witmer. Dept. of Biomedical Sciences, Ohio
University, Athens, OH (Ph: 740-593-9489)
Ryan C. Ridgely. Dept. of Biomedical Sciences, Ohio
University, Athens, OH
John R. Horner. Museum of the Rockies, Montana State
University, Bozeman, Montana
The strange bony crests found in
the skulls of the duck-billed dinosaurs known as
lambeosaurs come in a variety of sizes and shapes, even
in closely related species. These crests contain
incredibly long, convoluted nasal passages that loop up
over the tops of their skulls. Without any modern
animal with similar structures, paleontologists have
long debated the function of the crests. A new study
led by David Evans, a paleontologist at the Royal
Ontario Museum and the University of Toronto, used
CT-scanning to look inside the passages and cavities in
the skulls and reconstruct the brains and nasal cavities
of four different lambeosaur species. “The shape of the
brain can tell us a lot about what senses were important
in a dinosaur’s everyday life, and give insight into the
function of the crests” said Evans.
Paleontologists have debated the
function of lambeosaur crests since the 1920s. Some
suggested that they heightened the sense of smell by
increasing the surface area of the sensory tissue,
others that they functioned in temperature regulation,
and still others that the crests acted as sound
resonators for communication. “It’s difficult to infer
the function of structures in an extinct dinosaur when
there is so little resemblance to any living animal,”
said Jack Horner, a member of the team and
paleontologist at Montana State University. With the CT
scans, Evans and his team were able to circumvent the
problems of fossilization. “Even though the soft
tissues are not preserved in the fossils, the shape of
the bones that encase the brain and nasal passages are,”
said Evans. “From there, the anatomy of these missing
soft parts is easily interpreted.”
The CT scan results revealed a
mismatch between the external shape of the crest (which
no doubt functioned as a visual display) and the
internal shape of the nasal passages in closely related
species, suggesting a special function for the nasal
cavity. The portion of the brain responsible for the
sense of smell was relatively small and primitive,
indicating that the crest did not evolve to improve the
sense of smell. Computer models done by other
researchers suggest that the crests could have been used
to make low, eerie bellowing calls that could have been
used in communication, perhaps to call for mates or warn
others of predators. The CT scans documented a delicate
inner ear that confirms that the dinosaurs could hear
the low-frequency calls produced by the crest. “We were
surprised to see just how large the centers of the brain
associated with higher cognitive functions were”, said
Lawrence Witmer of Ohio University who, along with Ryan
Ridgely, performed the CT scanning and analysis. “We
suspected that the crested duck-billed dinosaurs used
both vocal and visual displays, but now we see that they
had the brain power and hearing to pull off these
behaviors,”
When all the available information
is put together, including the digital brain and ear
casts, the evolutionary relationships of the species,
and the growth pattern of the crest and its high degree
of variability in different co-existing species, it
supports the idea that the elaborate nasal cavity was
likely used to produce sounds for intraspecific
communication. This study demonstrates the power of
using an integrated approach combining 3D imaging,
growth studies, and phylogenetic sampling to test ideas
about the function and evolution of unusual structures
in extinct animals.
This project was supported by
grants from the National Science and Engineering
Research Council of Canada (Evans) and the National
Science Foundation (Witmer and Ridgely).
This
work will be published in part in an upcoming issue of
the journal The Anatomical Record.
Presentation
Time:
Thursday, October 16, 8:30 AM
People @ SVP who can comment:
Larry Witmer, Ryan Ridgely, Jack Horner, Peter Dodson,
David Weishampel
Note to
media: High-resolution images and animations of the
lambeosaurs can be viewed and downloaded here:
Media/SVP_dinosaur/SVP_dinosaur_media.htm
Case-sensitive login - username: svp-ou, password:
Dino12
|
