Original Description of Anchura (Helicaulax) popenoe Elder & Saul, 1996
- "Shell medium-sized, high-spired; pleural angle about 22 degrees; whorl profile slightly angulate just anterior to middle on spire and strongly angulate on last whorl; five whorls preserved in holotype; suture appressed; protoconch unknown; varices randomly present but not obvious; growth line antispirally concave on spire. Mature sculpture of slightly arched axial ribs, forming nodes at the periphery, 18 on penultimate whorl, axial ribs weakening on body whorl but persisting as nodes on carina; spiral cords strongest anterior to angulation on ultimate whorl, about six cords showing on spire whorls, third and fourth cords strongest, coalescing and forming noded keel on ultimate whorl and extending onto shank as carina, about six cords anterior of keel on ultimate whorl with second and third strongest. Outer lip expanded, forming narrow shanked wing with additional short posterior digit adjacent to spire."
Locus typicus: sandstone cropping out in bed of small NW-flowing gully tributary to French Creek, near south end of Swede Basin, Millville quadrangle, Shasta County, California, USA.
Stratum typicum: Coniacian, upper Cretaceous
Helicaulax ? popenoei is questionably included in Helicaulax because of its short posterior digitation that is adjacent to the spire at its base. Dockery (1993) includes species with similarly small posterior digitations in Anchura, but Helicaulax? popenoei bears so great a resemblance to Helicaulax tricosa that it is included in Helicaulax.