has been preparing fossils, creating skeletal reconstructions, and sculpting flesh models of prehistoric life at the University of Chicago since 2001. He also worked at the Field Museum of Natural History in exhibits, and learned many artistic skills in a former career: creating special effects and makeup for film, TV, and theatre.
Here's a few short clips of Mr. Keillor at work, from his web site:
Be sure to stop by Tyler's website; there are plenty of interesting photos, more videos and some informative articles as well. And here's a recent article with a bit more of his background: Paleoartist's skill brings dinosaurs to life.