| Lawrence M. Witmer,
PhD
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Common
Language Summary
The Visible Interactive Alligator Project at Ohio University and the University of Missouri. This page presents our work on the 3D anatomical structure of the head and skull of American alligator, Alligator mississippiensis . These resources are outgrowths of our more technical work and are intended to serve as STEM educational aids for K-12 and undergraduate students, as well as researchers. Our specimens include a "Day-0" hatchling, meaning it's from an animal that was stillborn on the day of hatching. We scanned the head region on the OUµCT scanner in 2009 at a resolution of 45µm (0.045 mm). We imported the scan data into workstations running Avizo and digitally extracted the bones and soft tissues. See the Pick-and-Scalpel blog post for details and to provide feedback. Four WitmerLab doctoral students participated, principally Dave Dufeau , who got the project started with the braincase and soft tissues, and Jason Bourke , who segmented the
rest of the bones
and made all the movies. Ashley Morhardt
and
Ruger Porter made the 3D PDFs. More recently, we scanned
a head of a subadult (OUVC 11415) at 50µm; this dataset was
visualized by Seishiro Tada of the University of Tokyo. We also include
some earlier WitmerLab work on an adult head. All of these
studies were funded by grants from the National Science
Foundation (NSF)
. This work is done
in collaboration with the Holliday Lab at the University of Missouri
. They
have comparable content on their 3D Alligator
site on an adult alligator.
Check out our other Visible Interactive Anatomy sites!
Some of the work
featured here has
been published:
• Dufeau, D. L., and L. M. Witmer. 2015. Ontogeny
of the middle-ear air-sinus system in Alligator mississippiensis
(Archosauria:
Crocodylia). PLOS ONE
10(9): e0137060.
doi:10.1371/journal. pone.0137060E.
PDF download here
. DICOM
data download for OUVC 10606 on Dryad
.
• Witmer, L. M., and R. C. Ridgely. 2008.
The paranasal air sinuses of predatory and armored dinosaurs
(Archosauria: Theropoda and Ankylosauria) and their contribution
to cephalic architecture. Anatomical Record 291:1362–1388
.
PDF download here
. DICOM data
download for OUVC 9761 on WitmerLab site
.
Sketchfab animations
Alligator hatchling: Middle-ear air sinus system by WitmerLab at Ohio University on Sketchfab
OUVC 10606 based on Dufeau & Witmer (2015)| 3D PDFs allow anyone with even the free Acrobat
Reader to interactively manipulate the 3D models that we
generate with powerful software like Avizo. The skull
and individual bones can be spun around, isolated, made
transparent, hidden, etc. The files can even be saved to
your local computer. We provide each 3D PDF in three
different resolutions and files sizes to match your
interest and the power of your computer. View our
mini-tutorial.
NOTE: Bugs in many browsers prevent them from running 3D PDFs in a browser window, so please save it to your system and then launch it. |
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| 3D PDF of the skull of a day-0
hatchling Alligator
mississippiensis
(OUVC
10606) with each
bone as a separate colored object. The right side and
left side can each be turned on and off or made
transparent. Unpaired bones (e.g., frontal) are assigned
to the right side. • Download a 22 MB 3D PDF LARGE • Download a 7.5 MB 3D PDF MEDIUM • Download a 3.5 MB 3D PDF SMALL |
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| 3D PDF of the skull of a day-0
hatchling Alligator
mississippiensis
(OUVC
10606) with soft
tissues such as the brain endocast, inner ear labyrinth,
blood vessels, nerves, and, added in Sept 2015,
paratympanic air sinuses based on Dufeau & Witmer (2015)
. Each bone is still a separate
object, but in this case, the bones are arranged in
anatomical groups (e.g., braincase), and individual
named bones (e.g., maxilla) can be turned on and off or
made transparent as left/right pairs. • Download a 25 MB 3D PDF LARGE • Download a 12 MB 3D PDF MEDIUM • Download a 6 MB 3D PDF SMALL |
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| 3D PDF of the skull of a subadult Alligator
mississippiensis
(OUVC 11415) with soft
tissues such as the brain endocast and tympanic air
sinuses. • Download a 87 MB 3D PDF LARGE • Download a 31 MB 3D PDF MEDIUM • Download a 17 MB 3D PDF SMALL |
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| 3D PDF of the skull of an adult Alligator
mississippiensis
(OUVC 9761) with soft
tissues such as the brain endocast, nasal cavity and
sinuses, and tympanic air sinuses. This 3D PDF derives
from the 2008 Witmer & Ridgely article in the Anatomical Record
.
• Download a 32 MB 3D PDF LARGE • Download a 12 MB 3D PDF MEDIUM • Download a 7 MB 3D PDF SMALL • Download a labeled image |
• Download a 70 MB QuickTime version (HD: 1920x1080)
• Download a 37 MB QuickTime version (1280x720)
• Download a 20 MB QuickTime version (800x450)
• Download a 15 MB QuickTime version (640x360)
• Download a 10 MB QuickTime version (480x270)
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| Exploded
skull animation.
Animation of the skull of a
day-0 hatchling Alligator
mississippiensis
(OUVC
10606), which explodes, revealing the
individual bones of the skull.
Jason Bourke and Dave Dufeau
segmented the skull in Avizo.
Jason Bourke labeled and
generated the animation in
QuickTime. |
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| Adult skull with air sinuses and brain endocast (roll).
Skull of Alligator mississippiensis
(OUVC 9761), revealing the brain endocast, nasal cavity and sinuses, and tympanic air sinuses. Rendered from CT scans using Amira and QuickTime by Ryan Ridgely, and labeled by Jason Bourke. This movie derives from the 2008 Witmer & Ridgely article in the Anatomical Record
.
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| Adult skull with air sinuses and brain endocast (yaw).
Skull of Alligator mississippiensis
(OUVC 9761), revealing the brain endocast, nasal cavity and sinuses, and tympanic air sinuses. Rendered from CT scans using Amira and QuickTime by Ryan Ridgely, and labeled by Jason Bourke. This movie derives from the 2008 Witmer & Ridgely article in the Anatomical Record
.
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| Sagittal CT slices
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CT scan slices in the sagittal plane of the head of Alligator mississippiensis
(OUVC 9761). Rendered from CT scans using Amira and QuickTime by Ryan Ridgely. This movie derives from the 2008 Witmer & Ridgely article in the Anatomical Record
.
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This project was funded by grants from the National Science Foundation .
| Ohio University Heritage College of Osteopathic Medicine Irvine Hall, Athens, Ohio 45701 740-593-2530 740-597-2778 fax |
Last updated:04/02/2019