Melanella, Bowdich, 1822

Souza, Leonardo Santos De, Pimenta, Alexandre Dias & Barros, José Carlos Nascimento De, 2021, Revision of the deep-sea Eulimidae (Gastropoda, Caenogastropoda) from off Northeast Brazil, Zootaxa 4927 (4), pp. 451-504 : 482-485

Melanella sp. 2

( Figure 18 A–F)

Material examined. Brazil: Ceará: (03°30′51″S 37°59′28″W, 384 m), RV Natureza, 07/xi/2001: MNRJ 35267 † [1 dd] ; Alagoas: (10°06′35″S 35°46′41″W, 720 m), RV Natureza, 16/xii/2001: MNRJ 35206 † [1 dd] ; Rio Grande do Sul: Off Solidão (30°46′S 49°07′W, 176 m), coll. RV Prof. Wladimir Besnard, 27/i/1972: MORG 17624 † [1 dd] .

Description. Shell conical, slightly curved, reaching about 8.5 mm long, 3.3 mm wide. Larval shell broken. Teleoconch with about 8.0 whorls, slightly convex outline, convexity accentuated in the lower region of each whorl; suture well demarcated, almost straight; subsutural zone indistinct; surface smooth, incremental scars well demarcated, appearing in intervals of about 1.1 whorl at the last two whorls. Last whorl about 50% of the shell length; base slightly truncated. Aperture high, pear shaped, acute posteriorly and rounded anteriorly; outer lip thin, opisthocline, sinuous, straight near the suture and strongly projecting, reaching the maximum projection at the mid of its height; inner lip thick, sinuous, sloping, reflected and well demarcated. Not umbilicate. Shell vitreous, colorless.

Measurements. MNRJ 35206†, 8 whorls (apex broken), SL= 8.5 mm; BWL= 4.5 mm; AL= 2.8 mm; SW= 3.3 mm; AW= 2.0 mm.

Remarks. The protoconch is broken in the three shells examined, but the relatively wide and solid shell, with a wide aperture and thick inner lip are characteristic enough to be worth noting ( Figure 18 A–F).

Melanella sp. 2 resembles M. doederleini ( Figure 11 A–I) in shape, but has bigger dimensions and a much more elongated aperture. Even with the apex broken, specimens of Melanella sp. 2 reaches 8 whorls and 8.5 mm long, while M. doederleini reaches 10 whorls and 3.6 mm long.

Melanella sp. 2 can also be distinguished from M. anapetes sp. nov. ( Figure 16 A–G) by the wider aperture, bigger dimensions, thicker inner lip and the curved spire.

Geographical distribution. Brazil: Ceará, Alagoas, Rio Grande do Sul (present study) .

Bathymetric distribution. From 176 m to 720 m.

Figures

FIGURE 11. A–I. Melanella doederleini (Brusina, 1886): A, B. Lectotype of Eulima doederleini Brusina, 1886, NHMUK 1979229; C, D, F, H, I. MNRJ 35208; E, G. MNRJ 35211. J. Eulima chyta Watson, 1883: syntype, NHMUK 1887.2.9.1604. H. Detail of protoconch, frontal view. I. Detail of protoconch, apical view. Scale bars: A–E= 1.0 mm; F, G= 200 µm; H, I= 100 µm. Credits: A, B, courtesy of NHMUK.

FIGURE 16. A–G. Melanella anapetes sp. nov.: holotype, MNRJ 35269. D. Detail of protoconch, frontal view. G. Detail of protoconch, apical view. Scale bars: A–C= 1.0 mm; D, G= 100 µm; E, F= 500 µm.

FIGURE 18. A–F. Melanella sp. 2: MNRJ 35206. D. Detail of the apex. Scale bars: A–C, E, F= 1.0 mm; D= 500 µm.