Here we describe a new latrunculid genus and species, Biverticillus tenuissimus gen. et sp. nov., from Walters Shoal on the Madagascar Ridge south of Madagascar in the Western Indian Ocean (Fig. 1A), the diagnostic microscleres of which are anisospinodiscorhabds, with two centrally located equidiametral whorls, equally spaced between each other and the apical whorl and manubrium. The microscleres are aniso- in their form because the apical and basal substructures differ slightly in the angle of repose of the spines.