I got a little too interested in the Comanche over the summer, which the article notes is actually a Ute word basically meaning "enemy". The Utes called them enemy because the Comanche prior to European contact lived in the Rockies much farther north. It was only the horse which allowed them to move out onto the plains. He's got them located in the plains of Texas, which again, they weren't at until probably after 1700 and when they were they completely dominated a region way bigger than that.
The Comanche emerged as a distinct group shortly before 1700, when they broke off from the Shoshone people living along the upper Platte River in Wyoming. In 1680, the Comanche acquired horses from the Pueblo Indians after the Pueblo Revolt. They separated from the Shoshone after this, as the horses allowed them greater mobility in their search for better hunting grounds.