Diagnosis. Height ca. 80% of length. Outer surface slightly sculptured by ca. 120 faint radial cords, and concentric, delicate undulations. Protoconch smooth, glossy.
Description. Shell size ca. 3 mm; broadly conical; slightly arched posteriorly; height ca. 80% of length. White, translucent, light beige apex. Protoconch white, of 1.5 rounded whorls; situated on right , forming posterior apex of foramen; smooth, glossy; size 320 µm. Foramen subterminal, diamond-shaped, width ca. 50% of length; dorsally located slightly turned anteriorly; ca. 10% of aperture area; edges rather irregular. Teleoconch conical; angle ca. 55°. Sculpture weak; minute, thin mosaic of small pustules aligned in radial rows, ca. 120 rows of pustules close to aperture, secondary cords (with about half shell height) intercalated between primary alignments ; distance of neighboring pustule on the rows approximately half of the width of the pustule; interspaces between rows as wide as rows. Commarginal undulations distinct. Aperture planar, elliptical, width ca. 85% of length; edges somewhat regular. Inner surface smooth, glossy. Septum ca. 50% of shell height (Fig. 115); about as tall as wide; ventral edge slightly concave, 42% of aperture width; gradually narrowing to posterior edge of foramen, constituting posterior and ventral floor of foramen.
Measurements (in mm). Holotype: 3.0 by 2.2;

Profundisepta denudata differs from P. profundi (Jeffreys, 1877) (McLean & Geiger, 1998: figs 3A-C), and from other congeneric species from North Atlantic as P. alicei (Dautzcnberg & Fischer, 1897); P. horroi (Farfante, 1947); P. sportella (Watson, 1883) (McLean & Geiger 1998), by the weak radial sculpture, the concentric undulations, and in being slender; the remaining shell features are similar. Profundisepta denudata differs from P. alicei (McLean & Geiger 1998: figs 3H-1), from the Azores and the Iberian-Moroccan Gulf, in being wider, having weaker radial sculpture, by the blunt shape of the posterior edge of foramen, and by the larger protoconch.

Distribution. Continental slope off Sao Paulo, Brazil.
Habitat, ca. 3000 m (dead specimens).