Shell medium-sized, chalky-white, claviform with orthoconoid spire and massive base. Protoconch not examined as the apex is strongly corroded. Teleoconch of about 9 whorls. Suture deeply canaliculate. Three early spire whorls flattened in outline, with widely set rounded folds pronounced throughout whorl height. Later whorls sculptured with strong, prominent, widely interspaced nodules, shifted towards lower suture, demarcating very wide and distinctly concave subsutural ramp. Nodules on penultimate and last whorl clearly squamiform, numbering 12 and 17 respectively. Axial sculpture of fine collabral growth lines well pronounced on late teleoconch whorls. Subsutural ramp on last whorl somewhat depressed; shell periphery gently convex, smooth, gradually sloping to robust shell base, also with no demarcation between shell base and siphonal canal.
Aperture ovate, outer lip simple, thin, with distinct stromboid notch and wide opening of siphonal canal. Anal sinus moderately deep, rounded. Inner lip smooth, with well-developed callus. Protoconch and early teleoconch whorls light brown, late whorls chalky-white; outer and inner lips white, and inside of aperture light brown.

The combination of smooth periphery of the last whorl, nodules shifted towards the lower aperture on spire whorls and the lack of any colouration on late teleoconch whorls easily distinguishes Clavus brianmayi n. sp. from the other species of the C. canalicularis complex. The stout shell of Clavus brianmayi n. sp. also resembles C. boucheti Kilburn, Fedosov & Kantor, 2014, but the latter species has rounded (not squami¬form) axial elements, and a light-orange spiral band on the periphery of last whorl.

New Caledonia.

The species name honours Brian Harold May CBE, British astrophysicist and guitarist, member of the band Queen.