Lawrence M. Witmer, PhD
Professor of Anatomy
Chang Professor of Paleontology

Dept. of Biomedical Sciences
Heritage College of Osteopathic Medicine
Life Science Building, Rm 123
Ohio University
Athens, Ohio 45701 USA

Email: witmerL@ohio.edu

 

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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 William Porter made the 3D PDFs. We also include some earlier WitmerLab work on an adult head. 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 skull by WitmerLab at Ohio University on Sketchfab

Alligator hatchling: Middle-ear air sinus system by WitmerLab at Ohio University on Sketchfab

OUVC 10606 based on Dufeau & Witmer (2015)
3D PDFs Videos
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.

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
 

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
 

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

 

 
Labeled skull animation. Animation of the skull of a day-0 hatchling Alligator mississippiensis (OUVC 10606), labeled to show 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.
•
Download a 70 MB QuickTime version (HD: 1920x1080)
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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)
 
 

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.
• Download a 32 MB QuickTime version (HD: 1920x1080)
•
Download an 18 MB QuickTime version (1280x720)
•
Download an 11 MB QuickTime version (800x450)
• Download an 8 MB QuickTime version (640x360)

 
 

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..
• Download a 26 MB QuickTime version (1320x864)
• Download a 16 MB QuickTime version (969x634)
• Download a 9 MB QuickTime version (660x432)
NOTE: this movie appeared on CSI: Miami on CBS

 
 

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..
• Download a 16 MB QuickTime version (1216x626)
• Download a 11 MB QuickTime version (954x491)
• Download a 5 MB QuickTime version (608x313)

 
 

Sagittal CT slices. 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..
• Download a 5.4 MB QuickTime version (906x408)
• Download a 2.6 MB QuickTime version (548x247)
NOTE: this movie appeared on CSI: Miami on CBS

Witmer is responsible for the content of the website. Content provided here is for educational and research purposes only, and may not be used for any commercial purpose without the permission of L. M. Witmer and other relevant parties.

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: 10/25/2016