Calyptaulax is a genus of trilobites in the order Phacopida that existed during the middle and upper Ordovician in what is now the U.S. states of New York, Pennsylvania, Oklahoma, Illinois, Missouri, Virginia, Vermont, Nevada, Iowa, Wisconsin, Kentucky, and Iowa, as well as the Canadian provinces of Ontario, Newfoundland and Labrador, Quebec, and the territory of Nunavut. Other countries Calyptaulax fossils are known from include Ireland, Norway, Russia, and the United Kingdom.
By original designation; Calyptaulax glabella <small>Cooper, 1930</small>: pp. 388 - 389, pl. 5, figs. 9 - 11. From the Matapedia Group (Ashgill), Perce, Quebec, Canada.