Melanella anapetes, Souza & Pimenta & Barros, 2021

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 : 480-482

Melanella anapetes sp. nov.

urn:lsid:zoobank.org:act:8AC38413-2C40-42F0-847F-A816B71BD34B

( Figure 16 A–G)

Type material. Holotype MNRJ 35269 † ( Figure 16 A–G) . Paratype: Brazil: Off Bahia state, REVIZEE Nordeste (11°35′30″S 37°12′18″W, 510 m), 30/x/2000: MNRJ 35281 † [1 dd] .

Type locality. Brazil: Off Alagoas, REVIZEE Nordeste (10°06′35″S 35°46′41″W, 720 m), coll. RV Natureza, 16/xii/2001 .

Etymology. From anapetes Gr. , which means wide open, expanded; relative to the elongated aperture of the species.

Description (Holotype). Shell conical, elongated, apex obtuse, reaching 8 whorls, 4.4 mm long, 1.2 mm wide. Larval shell conical, smooth, transition to teleoconch indistinct. Teleoconch whorls convex; suture well demarcated, sloping; surface smooth; incremental scars slightly demarcated, appearing in irregular intervals. Last whorl almost 60% of the shell length; base rounded, elongated. Aperture high and narrow, pear shaped, acute posteriorly and rounded anteriorly; outer lip thin, prosocline, sinuous, projecting gradually from the suture and reaching the maximum projection in the middle of the height; inner lip sinuous, slightly twisted, sloping and well demarcated. Not umbilicate. Shell vitreous.

Measurements. Holotype MNRJ 35269†, 8 whorls, SL= 4.4 mm; BWL= 2.5 mm; AL= 1.6 mm; SW= 1.2 mm; AW= 0.8 mm.

Remarks. The slightly twisted columella resembles species of Haliella Monterosato, 1878 , but the latter genus usually comprises species with cylindrical shell and a blunt apex ( Bouchet & Warén 1986: 338). We prefer to include this species in Melanella because of its conical shape ( Figure 16A, B ), including that of the protoconch ( Figure 16D ).

Melanella anapetes sp. nov. has a broad aperture ( Figure 16E ) like M. hians ( Figure 9J ), but it is less expanded laterally and the former species is much smaller (holotype: 8 whorls, SL= 4.4 mm, SW= 1.2 mm v s. syntype of M. hians NHMUK 1887.2.9.1588: 10 whorls, SL= 10.1 mm, SW 3.3 mm).

Melanella anapetes sp. nov. resembles M. adiastalta sp. nov. ( Figure 15 A–G) in the outline of the outer lip, but has a more elongated shell shape (ratio SW/SL= 0.28 vs. 0.37 in M. adiastalta sp. nov.) and aperture (ratio AW/AL= 0.5 vs. 0.6).

Melanella anapetes sp. nov. differs from M. doederleini ( Figure 11 A–I) and M. sarissa ( Figure 12 A–L) by the more elongated aperture (ratio AW/AL= 0.5, 0.7 and 0.6, respectively).

Geographical distribution. Brazil: Alagoas and Bahia .

Bathymetric distribution. From 510 to 720 m.

Figures

FIGURE 9. A–I. Eulimacrostoma phorcys sp. nov. A, B. Holotype, MNRJ 23191. C–I. Paratype, MNRJ 35191. J. Melanella hians: syntype of Eulima hians Watson, 1883, NHMUK 1887.2.9.1588. E. Detail of teleoconch surface. H. Detail of protoconch, frontal view. I. Detail of protoconch, apical view. Scale bars: A–D, I= 1.0 mm; E= 200 µm; F, G= 500 µm; H= 100 µm. Credits: J, courtesy of NHMUK

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 12. A–L. Melanella sarissa (Watson, 1883):A, B. Holotype of Eulima sarissa Watson, 1883, NHMUK 1887.2.9.1599; C. NMW 1955.158.26254. D, L. Syntype of Melanella cinca Dall, 1927, USNM 108028. E. MNRJ 28845. F–K. IBUFRJ 19708. J. Detail of protoconch, frontal view; arrow indicates transition protoconch-teleoconch. K, L. Detail of protoconch, apical view; arrow indicates transition protoconch-teleoconch. Scale bars: A–G= 1.0 mm; H, I= 200 µm; J= 100 µm; K= 50 µm; L= 75 µm. Credits: A, B, courtesy of NHMUK; C, courtesy of NMW; D, L, courtesy of USNM.

FIGURE 15. A–G. Melanella adiastalta sp. nov.: holotype, MNRJ 35250. F. Detail of protoconch, frontal view. G. Detail of protoconch, apical view. Scale bars: A–C= 1.0 mm; D, E= 200 µm; F, G= 100 µm.

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.