Shell large, maximum height 66.8 mm, thick, moderately inflated (diameter / height, 0.58 to 0.64), moderately high-spired (aperture height / shell height, 0.53 to 0.59), weakly constricted at base; spiral sculpture of last whorl consisting of six principal cords, one at shoulder angulation, a second immediately below shoulder, a central cord ending in blunt labral tooth, and two or three basal cords; fine threads separating principal cords; axial sculpture of last whorl consisting of eight strong rounded ribs, forming nodes at intersections with the three upper cords; outer lip convex in central sector, with strong adapical and weakly concave abapical sinus; adaxial side of outer lip with eleven to twelve strong beaded lirae; aperture relatively broad, its height / breadth ratio 2.4 to 2.7; canal relatively long, canal height / aperture height ratio 0.38 to 0.42; umbilical slit absent; aperture light peach-colored.

Shell: Shell somewhat elliptical fusiform, maximum length of 46.6 mm, ~ twice as long as wide; color chestnut to brown, its nodes slightly faded. Spire high with angle varying from 75° to 80°, spire length about half of total shell length. Protoconch small, with two whorls, smooth; terminal varix low. Teleoconch with up to five and a half whorls, shaped convex by two angulations, one at shoulder and the other at central cord, subsutural ramp concave, suture impressed; base of shell concave. Spiral sculpture of five to seven main cords: one at shoulder, one marking a central cord and one between these two, another two to four cords at base; several other fine cords throughout the entire teleoconch. Axial sculpture of 8 to 10 strong ribs forming elevated nodes where they cross the three upper spiral cords, shoulder nodes more prominent. Aperture roughly elliptical to slightly pyriform, height ~ twice the width. Columella bearing three to four small folds in its center. Outer lip thin, marked internally by nine to 12 beaded lirae, small and blunt labral tooth at end of central cord may be present. Siphonal canal small, its length -1/3 of total aperture height. Siphonal fasciole distinct. Umbilical slit absent. Soft Parts: as in Leucozonia nassa. Male genital System not examined due to lack of male specimens. Operculum: as in Leucozonia nassa.
Radula: radula long and thin; radular sac extending beyond the posterior end of odontophore; rachidian tooth straight, rectangular, its base with a concave outline and its cusped margin of convex outline, bearing three sharp cusps, the central one slightly larger; lateral tooth wider then long, bearing six centrally recurved cusps, the innermost being about twice as long as the others which have approximately the same size, except for the outermost, slightly smaller; lateral margin acute, ending in a more external, last cusp; occurrence of a denticle-like projection on inner margin of the innermost cusp.

Endemic to Ilha Trindade, Brazil.

In our earlier paper (Vermeij and Sny¬der, 1998), we distinguished L. ponderosa as a distinct species based on four specimens. Since we published the description of L. ponderosa, we have seen two additional specimens, one of which we illustrate in Figures. This new material reinforces our original conclusion that L. ponderosa is consistently distinct from but closest to L. nassa, which also occurs at Ilha Trindade. In the typical form of L. nassa, the upper two principal cords lie very close together, whereas in L. ponderosa the second cord lies approximately midway between the shoulder angulation and the central cord. We have not seen this pattern in any other western Atlantic Leucozonia. The possibility remains that L. ponderosa is a local variant of the widespread L. nassa. For the time being, however, we continue to recognize L. ponderosa as a separate species, and we hope that molecular investigations will resolve the status of this and other insular populations of Leucozonia.