(Figs. 1–2)
Aliceia aenigmatica Dautzenberg & Fischer, 1897 a: 45: Dautzenberg & Fischer (1897 b: 182, pl. 4, figs. 15–18); Dautzenberg (1927: 69, pl. III, figs. 24–27); Bouchet & Warén (1980: 91, figs. 190, 230);
Clavus aenigmatica (Dautzenberg & Fischer, 1897): Powell (1966: 70, pl. 10, fig. 21).
Type material: In Museé Océanographique de Monaco.
Type locality: Azores, Princesse Alice (1896), sta. 53 (38 º 20 ’N, 30 º 25 ’W), 1550 m; sta. 69 (39 º 11 ’N, 33 º 04’ 55 ”W), 1846 m; sta. 74 (39 º 21 ’ 20 ”N, 33 º 26 ’W), 1360 m; sta. 90 (39 º 11 ’N, 32 º 44 ’ 30 ”W), 1600 m.
Material examined: 18439 [2] OP II # 45; 18440 [1] OP II # 50 A; 18441 [2] OP I # 61; 18442 [1] OP I # 44.
Description: Shell high, slender, white, up to 4.02 mm long. Protoconch with four whorls, light yellow. Protoconch 1 slightly darker, with granulation near the suture. First whorl of protoconch 2 with a subsutural row of nodules, which gradually disappear on the second whorl. Protoconch 2 with a thin middle keel and straight evenly spaced axial riblets below it, extending only slightly above it. Transition from protoconch to teleoconch gradual, the sculpture of the protoconch slowly fades into the smoothness of the teleoconch. Teleoconch with about 2 3 / 4 whorls with an angulation in their upper region. Several fine faint axial scars cross the entire surface of the whorls. Scars are curved in a C shape below the angulation, and they are inverted above it. Remnants of the posterior siphonal canal are retained as the animal grows, and are visible every half whorl. Base slightly convex with a large, broad and deep umbilicus. Anal sinus broad and deep, forming a posterior siphonal canal. Anterior siphonal canal wide and moderately long. Aperture elliptical.
Geographic distribution: Northeast Atlantic: Azores (Dautzenberg & Fischer, 1897 a; Dautzenberg & Fischer, 1897 b; Dautzenberg, 1927); Azores and Portugal (Bouchet & Warén, 1980). Southwest Atlantic: Campos Basin, Rio de Janeiro (this paper). Bathymetry: 750 m (this paper)– 1980 m (Bouchet & Warén, 1980).
Discussion: Powell (1966: 70) considered the genus Aliceia as a possible synonym of Clavus. He mentioned, however, that this cannot be confirmed since the type species Aliceia aenigmatica is represented by a juvenile. Bouchet & Warén (1980: 90) added that anatomical study was necessary to settle the matter; in their paper they also reported the collection of a young specimen of A. aenigmatica. Here, we report the occurrence of this rare species for the first time in South Atlantic waters. The material studied here is as young as Bouchet & Warén’s, and we have only empty shells as well.
We also increase the known bathymetric range for A. aenigmatica. The shallowest depth previously reported for this species was 1360 m (Dautzenberg & Fischer, 1897 a) and it has now been found at 750–1350 m.