Famelica mirmidina Dautzenberg & Fischer 1896

Famelica mirmidina Dautzenberg & Fischer, 1896

(Figs. 3–4)

Pleurotoma mirmidina Dautzenberg & Fischer, 1896: 413, pl. XVII, fig. 13; Dautzenberg & Fischer (1897b: 146); Dautzenberg (1927: 68, pl. III, fig. 23).

Famelica mirmidina: Bouchet & Warén (1980: 90, figs. 188, 280, 281); Absalão et al. (2005: 35, figs. 105, 117); Rios (2009: 353, species 916).

Type material: In Museé Océanographique de Monaco.

Type locality: Azores, Princesse Alice (1895) sta. 46 (37°42,40’N, 27°27,30’W), 1385 m.

Material examined: 18443 [1] B # 32; 18444 [4] OP I # 47; 18445 [6] OP I # 48; 18446 [4] OP I # 52; 18447 [4] OP I # 53; 18448 [4] OP I # 58; 17060 [1] OP I # 59; 18449 [1] OP I # 60; 18450 [3] OP I #61; 18451 [4] OP I # 62; 18452 [4] OP I # 63; 18453 [1] OP I # 75; 18454 [1] OP I # 78; 18455 [1] OP I # 83; 16965 [3] OP II # 45; 18456 [5] OP II # 48; 18457 [2] OP II # 50A; 18458 [2] OP II # 52; 18459 [11] OP II # 53; 18460 [2] OP II # 58; 18461 [1] OP II # 60; 18462 [2] OP II # 61; 18463 [6] OP II # 62; 18464 [4] OP II # 63; 18465 [6] OP II # 68; 18466 [3] OP II # 73; 18467 [1] OP II # 75; 18468 [1] OP II # 77; 18469 [1] OP II # 82; 18470 [2] OP II # 83; 18471 [1] OP II # 84; 18472 [1] OP II # 86; 18473 [2] OP II # 87.

Description: Shell high, slender, white, up to 8.68 mm long. Protoconch with five whorls, light yellow. Protoconch 1 granulose and slightly darker. Protoconch 2 with a middle keel, straight, evenly spaced axial riblets below it, a subsutural row of large nodules and several smaller nodules between the axial riblets and the subsutural row. Clear-cut transition from protoconch to teleoconch. Teleoconch with four whorls of convex profile. Slight and low rounded spiral cord below the upper 1/3 of each whorl and several fine faint axial scars cross the entire surface of the whorls. Scars curved in a C shape below the spiral cord and inverted above it. Suture moderately deep. Base smooth except for the axial scars. Inner lip not entirely pressed against the parietal wall, forming a narrow chink. Anterior siphonal canal short.

Geographic distribution: Northeast Atlantic: Azores (Dautzenberg & Fischer, 1896; Dautzenberg & Fischer, 1897b; Dautzenberg, 1927) Azores and Portugal (Bouchet & Warén, 1980). Southwest Atlantic: Espírito Santo and Bahia States, Brazil (Absalão et al., 2005); Campos Basin, Rio de Janeiro (this paper). Bathymetry: 750 m (Absalão et al., 2005)– 3360 m (Bouchet & Warén, 1980).

Discussion: The shell in this species is extremely thin and fragile. In all specimens studied here, the outer lip is broken, making it impossible to describe the aperture or the anal sinus. The holotype is broken in the same manner, and apparently so was the material studied by Bouchet & Warén (1980: 89, fig. 188).

Four species of Famelica are assigned to the western Atlantic (Rosenberg, 2009): Famelica mirmidina (Dautzenberg & Fischer, 1896), F. monoceros (Watson, 1881), F. scipio (Dall, 1889) and F. catharinae (Verrill & Smith, 1884). Bouchet & Warén (1980) mentioned the narrow chink as a unique feature that differentiates F. mirmidina from all other known Turridae from the eastern Atlantic, in which the inner lip is completely pressed against the parietal wall, precluding the formation of the chink. The same difference applies to the western Atlantic Famelica, among which F. mirmidina is the only one that has the chink. Also, F. mirmidina has a faint spiral cord, unlike the other species, which show abundant spiral ornamentation.

Famelica mirmidina was reported in Brazil for Bahia and Espírito Santo States (13°–19°S). Its distribution is here expanded further South to include Rio de Janeiro (21°–22°).