(Figs. 12–13)
Pleurotoma dalmasi Dautzenberg & Fischer, 1897 a: 39: Dautzenberg & Fischer (1897 b: 153, pl. 3, fig. 4); Xanthodaphne dalmasi (Dautzenberg & Fischer, 1897): Bouchet & Warén (1980: 66, figs. 28, 236, 237).
Type material: In Museé Océanographique de Monaco.
Type locality: Azores, Hirondelle (1888), sta. 20 (40 º 05’N, 29 º 48 ’W), 1850 m; sta. 47 (39 º 18 ’ 05”N, 33 º 32 ’ 15 ”W), 1372 m; sta. 69 (38 º 33 ’ 21 ”N, 30 º 28 ’ 54 ”W), 1300 m; Princesse Alice (1895), sta. 46 (37 º 42 ’ 40 ”N, 27 º 25 ’ 30 ”W), 1385 m; sta. 71 (38 º 26 ’N, 28 º 51 ’W), 1165 m; sta. 117 (38 º 59 ’N, 30 º 38 ’ 20 ”W), 2102 m; 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; sta. 109 (37 º 40 ’N, 28 º 46 ’ 30 ”W), 1919 m.
Material examined: 18495 [1] B # 32; 18496 [3] OP II # 44; 17856 [3] OP II # 45; 18098 [2] OP II # 47; 18497 [2] OP II # 48; 18101 [1] OP II # 50; 18140 [1] OP II # 50 A; 18138 [4] OP II # 52; 18498 [6] OP II # 53; 15576 [1] OP II # 54; 18767 [1] OP II # 57; 18499 [1] OP II # 58; 18768 [2] OP II # 61; 18500 [7] OP II # 62; 18501 [1] OP II # 63; 15915 [2] OP II # 67; 17769 [1] OP II # 68; 18770 [1] OP II # 70; 18502 [1] OP II # 72; 18503 [9] OP II # 73; 18504 [6] OP II # 75; 18505 [4] OP II # 78; 18771 [1] OP II # 80; 18506 [9] OP II # 83; 18507 [3] OP II # 86; 18508 [5] OP II # 87; 17868 [2] OP I # 44; 18509 [4] OP I # 45; 17899 [4] OP I # 47; 18510 [2] OP I # 48; 18511 [1] OP I # 52; 18512 [7] OP I # 53; 17919 [1] OP I # 61; 18513 [4] OP I # 62; 15865 [2] OP I # 68; 17999 [1] OP I # 72; 18514 [3] OP I # 73; 15418 [3] OP I # 74; 18008 [1] OP I # 75; 18010 [1] OP I # 77; 18515 [4] OP I # 78; 18516 [3] OP I # 83; 18029 [3] OP I # 86; 18517 [4] OP I # 87.
Description: Shell moderately plump, white, up to 4.94 long. Protoconch with about 3.5 whorls, yellowish. Protoconch 1 with rows of tiny crosses. Protoconch 2 with diagonal cancellation on the lower 3 / 4 of the whorls and axial riblets on the upper 1 / 4. Clear-cut proto-teleoconch boundary. Teleoconch whorls evenly rounded, with a very gentle shoulder. Weakly curved axial riblets in the subsutural zone, just below the suture. Sculpture of faint, gently undulating, low spiral cordlets below the shoulder, vanishing at the base. Suture shallow. Base moderately long and convex with inflexion to form a broad anterior siphonal canal. Fasciolar region with about six oblique and very faint cords. Anal sinus shallow and wide. Inner lip not discernible. Parietal wall curved. Outer lip thin. Aperture ovoid.
Geographic distribution: Northeast Atlantic: Azores (Dautzenberg & Fischer, 1897 a; Dautzenberg & Fischer, 1897 b); Azores, Portugal and Canary Islands (Bouchet & Warén, 1980). Southwest Atlantic: Campos Basin, Rio de Janeiro (this paper). Bathymetry: 698 m (this paper)– 2900 m (Bouchet & Warén, 1980).
Discussion: There are seven species of Xanthodaphne reported from the Western Atlantic (Rosenberg, 2009): X. translucida (Watson, 1881), X. bruneri (Verrill & Smith, 1884), X. leptalea (Bush, 1893), X. pachia (Watson, 1881), X. sofia (Dall, 1889), X. pompholyx (Dall, 1889) and X. heterogramma (Odhner, 1960). According to Numanami (1996: 222), X. translucida has a smooth protoconch (Watson, 1886, 330, pl. 25, fig. 11) and should be classified in another genus. Xanthodaphne dalmasi can be distinguished from any other species of this genus by its typical sculpture of softly undulating low spiral cordlets; whereas in all other congeners the spiral sculpture is rectilinear.
Xanthodaphne dalmasi is here reported for the first time in South Atlantic waters. It was previously known to occur in Azores, Portugal and Canary Islands. Its bathymetric range is also increased. The shallowest depth previously reported was 1165 m (Dautzenberg & Fischer, 1897 a) and it has now been found at 698 m.