There are 14 recognized species of horned lizards also know as horn
toads. The shape and size of the horns of the species varies greatly. So what did the
ancestors of the recent species look like? That is the
question
Dr. Wendy Hodges
asked. What she did to try to find out was take genetic samples form known species and
look at genetic results to better understand which species are more closely related. This work
resulted in a hypothetical
phylogenetic map or
something similar to a family tree of
the horned lizards ancestors. This told her with some certainly which two species
were more closely related but did not give her an image of what the skull and horns look
like of the ancestors. For this she asked me to help. She took
X-ray CT scanns of different species and looked at the morphology of the horns. She
would then take the 3D shape of the skull of two closely related horned lizards and morph
in 3D into a hypothetical 3D model of the ancestor’s skull. Using X-ray CAT scan
data and computer programs written to morph 3D models, she was able to get a rough idea
of what an ancestor looked like. This work could possibly help her and others
researchers identify fossilized skull specimens found out in the field by paleontologists.
More links about this resarch are below.
Poster displayed for TACC at SC2002
NPACI Envision article 2003
SIGGRAPH 2003
Digital movie of 3D rendering for SC2003 (YouTube)
National Science Foundation Multimedia Gallery 2003
Featured Wide screen 3D rendering for Science Showcase at UT November 2003
Featured for NPACI San Diego Supercomputer Center Calander 2004 month of July
IEEE Visualization 2004
Article about Horned Lizards
Below are two images. The first image is of two horned lizards, Phrynosoma cornutum (Texas horned lizard) and
Phyrynosoma tauris (Mexican Horned lizard). The colors are not real, they represents the distance from the
skin to the bone. The second image is of the Texas horned lizard also with false color using three
different color attributes from 3D x-ray data.
