Original description: Cortical shell large, spherical in outline, with two polar spines approximately equal in length. Shell comprised of small pentagonal and hexagonal pore frames with thin rims and deep walls; small pointed nodes at pore frame vertices. Spines relatively short (less than diameter of shell), and fairly constant in width. Spines triradiate with wide rounded ridges and narrow grooves; ridges terminate with small thorns, raised at right angles to axis of spine. Spine tips circular in axial section.

Original remarks: Xiphostylus duvalensis n. sp. differs from X. simplus Yeh in having spines whose ridges terminate in small thorns.

Etymology: Species named for Duval Rocks, west of type locality on north shore of Cumshewa Inlet, Queen Charlotte Islands.

Xiphostylus duvalensis was named by Gorican et al. (2006). Its type specimen is GSC 111788 and is a 3D body fossil. Its type locality is Cumshewa Inlet, Moresby Island, GSC loc. C-080610, which is in a Pliensbachian marine shale/limestone in the Fannin Formation of Canada.