Published: Aug. 4, 2021

The giant horned lizard is endemic to the Pacific coast of southern Mexico. It is the largest species of horned lizard, reaching up to 8 inches from snout to tail. Multiple rows of scales that have been modified into large pointy spines cover its body, forming an intimidating armor.

This video captures a computerized tomography or CT scan of the head of a giant horned lizard currently stored in a jar of ethanol in the CU Museum’s Herpetology Collection. CT scanning enables researchers to visualize the skeletal anatomy within the pickled specimen without performing a destructive dissection. By compiling multiple x-ray “slices” taken at different angles into a single three-dimensional image, CT scans allow for precise measuring and exploration of internal body structures. Among other things, this scan illustrates that the spikes on the top of the head are true horns with a boney core, distinct from the modified scale spines covering the rest of the lizard’s body. Thanks to museum technologies such as this, we know more information about what lies within this 47-year-old giant horned lizard, and both the specimen and CT scan can be used again and again to answer different future research questions.

Over the next several years, a team of museum staff and students at CU Boulder will collect high-tech 2D and 3D images of roughly 1,100 species of reptiles and amphibians housed in the CU Museum’s collections.The effort is a partnership with the University of California Berkeley and University of Florida, called oMeso and is funded by the U.S. National Science Foundation. The main focus of this effort is on animals from Mesoamerica. The images will be publicly available through theand an exhibition in both English and Spanish is scheduled for 2023.


UCM 51066 Phrynosoma asio
5 August 1973
Mexico, Colima


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