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

publication ID

https://doi.org/10.11646/zootaxa.4927.4.1

publication LSID

lsid:zoobank.org:pub:AED51D9E-1751-4010-A8E1-B72AE428821A

DOI

http://doi.org/10.5281/zenodo.4557507

persistent identifier

http://treatment.plazi.org/id/03E687A2-FFA1-FFC1-FF5F-8666FDC242B4

treatment provided by

Plazi

scientific name

Melanella
status

 

Melanella   sp. 1

( Figure 17 View FIGURE 17 A–G)

Material examined. Brazil: Off Pernambuco, REVIZEE Nordeste (08°46′00″S 34°44′00″O, 690 m), coll. RV Natureza, 18/xi/2000: MNRJ 35251 View Materials † [1 dd] GoogleMaps   .

Description. Shell subcylindrical, straight, reaching about 3.6 mm long, 1.0 mm wide. Larval shell vitreous, cylindrical, with about 2.0 whorls, 370 µm wide; smooth, except for microscopic striations close to suture, transition to teleoconch marked by an almost indistinct incremental scar. Teleoconch with about 7.0 whorls, flat outline; suture almost indistinct, sloping; subsutural zone about 20% of the whorl height; surface polished, sculptured by straight axial lines spaced every 10–15 μm ( Figure 17D View FIGURE 17 ); incremental scars slightly demarcated, appearing at irregu-lar intervals. Last whorl about 40% of the shell length; base rounded. Aperture short, pear shaped, acute posteriorly and rounded anteriorly; outer lip thin, opisthocline, sinuous, slightly retracting near the suture and after projecting, maximum projection in the lowermost third of the height, retracted in distal region; inner lip sinuous, sloping, reflected, well demarcated. Not umbilicate. Shell colourless.

Measurements. MNRJ 35251†, 9 whorls, SL= 3.6 mm; BWL= 1.4 mm; AL= 0.9 mm; SW= 1.0 mm; AW= 0.5 mm.

Remarks. The species that most resembles Melanella   sp. 1 ( Figure 17 View FIGURE 17 A–G) is Melanella jeffreysi ( Tryon, 1886)   ( Figure 17 View FIGURE 17 H–J), with the subcylindrical shape, dome shaped apex, similar outline of the outer lip and similar dimensions of the protoconch (~ 370–380 µm wide) and teleoconch. According to Jeffreys (1884), the shell surface of M. jeffreysi   (as “ Eulima solida   ”) is covered by longitudinal, extremely thin axial lines, but Bouchet & Warén (1986) disagree with Jeffrey’s description. The latter authors commented that there are “only a few scattered, indistinct, very thin axial lines”, and that Jeffrey’s description is possibly related to a specimen collected in the PORCUPINE 1869 Expedition stn. 23. Bouchet & Warén (1986) identified the latter specimen as M. orphanensis   despite uncertainties. We examined the lectotype of E. solida   (USNM 133126) under SEM and verified that the teleoconch surface is almost entirely smooth, marked only by strong incremental scars ( Figure 17J View FIGURE 17 ). Melanella   sp. 1 has thin axial lines, distributed over the whole teleoconch in extremely small intervals ( Figure 17D View FIGURE 17 ).

Melanella   sp. 1 differs from M. orphanensis   ( Figure 17K View FIGURE 17 ) by the straight spire, with shallower sutures and a slower increasing diameter.

Despite the differences mentioned above, we refrain to describe Melanella   sp. 1 as new because there are several Melanella   s.l. with a subcylindrical shape currently known or awaiting description ( Bouchet & Warén 1986; Personal observation). We prefer to wait for new material to become available.

Geographical distribution. Brazil: Pernambuco.

Bathymetric distribution. 690 m.