Inella spinosa, Fernandes, 2024

Fernandes, Maurício Romulo, 2024, Triphoridae (Gastropoda) from Martinique sampled by the MADIBENTHOS expedition, with notes on shallow-water species from Guadeloupe, Zoosystema 46 (18), pp. 457-503 : 462

Inella spinosa n. sp.

( Fig. 4 )

urn:lsid:zoobank.org:act:42468F50-0E06-472E-8F1D-5738EF4F29B5

TYPE MATERIAL. — Holotype. Martinique. MADIBENTHOS • sh; Macouba, region ‘Nord Atlantique’ ; sta. AD275, 14°55’00”N, 61°08’54”W; depth 80 m; MNHN-IM-2000-38595 .

Paratypes. Martinique. MADIBENTHOS. ‘Nord Atlantique’ • 2 sh; sta. AD263; MNHN-IM-2000-38596 .

TYPE LOCALITY. — Martinique: Macouba, region ‘Nord Atlantique’; MADIBENTHOS expedition sta. AD275, 14°55’00”N, 61°08’54”W; 80 m.

OTHER MATERIAL EXAMINED. — Guadeloupe. KARUBENTHOS 2 • 1 sh; sta. DW4545; MNHN.

Martinique. MADIBENTHOS. ‘Nord Atlantique’ • 1 sh [juvenile, worn]; sta. AD260; MNHN.

ETYMOLOGY. — From Latin, spinosus. The species is named due to the spiny appearance of the spiral cords of teleoconch.

DIAGNOSIS. — Spirally-elongated, pointed nodules in median and abapical cords, giving a spiny appearance to the teleoconch profile; adapical spiral cord initially very narrow, never reaching the same size of other cords; shell with a cream background.

GEOGRAPHIC DISTRIBUTION. — Guadeloupe and Martinique.

BATHYMETRIC DISTRIBUTION. — Recorded depth in Guadeloupe: 60- 82 m. Recorded depth in Martinique: 78- 80 m.

DESCRIPTION

Shell sinistral, conical/fusiform, rectilinear profile, up to 4.4 mm long, 1.1 mm wide, length/width ratio 3.5-3.9; adult shells reach at least 2.7 mm in length. Protoconch paucispiral with truncated apex, without clear differentiation from the teleoconch, of 2.75-3.0 whorls, 0.57-0.61 mm long, 0.50-0.52 mm wide; the small nucleus rises in an adapical direction and further goes abapical in an oblique descent; two smooth, keeled spiral cords of equal size, situated at 26-34% and 66-71% of last whorl height, in addition to a narrow and smooth subsutural cord. Teleoconch with up to 8.5 whorls; two main spiral cords (median and abapical) at the beginning, continuous to those of protoconch, assuming a keeled-shape along the teleoconch, with median cord always more prominent, except on the body whorl where both cords have nearly the same size; adapical spiral cord initially very narrow, gradually strengthening along the teleoconch but never reaching the same size of other cords or forming distinct nodules; a smooth sutural cord is also evident, gradually strengthening and reaching the same size of adapical cord in larger shells; spirally-elongated, pointed nodules in median and abapical cords, giving a spiny appearance to the teleoconch profile; nine to ten orthocline axial ribs on seventh teleoconch whorl; suture distinct; smooth subperipheral cord, one narrow, smooth basal cord; supranumerical cords absent; elliptical aperture, 0.51-0.67 mm long, 0.37-0.44 mm wide, length/width ratio 1.4-1.5; open, very short anterior canal, 0.05-0.12 mm long, 0.18-0.27 mm wide, length/width ratio 0.3-0.5; posterior canal absent. Shell with a cream background, white nodules on teleoconch, internodular spaces light brown.

REMARKS

The spiny appearance of the spiral cords of the teleoconch, combined with the color pattern and small shell size (reaching only 4.4 mm long), makes I. spinosa n. sp. unique among Inella and other West Atlantic triphorids. Because of its probable lecithotrophic development and bathymetric range restricted to the upper 100 m (absent from deeper waters of Guadeloupe, based on samples from KARUBENTHOS 2), I. spinosa n. sp. probably has a narrow geographic range in the Lesser Antilles. The single shell obtained from Guadeloupe ( Fig. 4D ) has the axial sculpture much weaker than shells from Martinique ( Fig. 4 A-C), attenuating the spiny appearance of the spiral cords.

Figures

FIG. 4. — Inella spinosa n. sp.: A, G-H, MNHN-IM-2000-38595, holotype, 4.4 mm; B, C, E, F, MNHN-IM-2000-38596, paratypes, sta. AD263, 3.9 mm, 2.9 mm; D, MNHN, sta. DW4545 (KARUBENTHOS 2 expedition), 2.7 mm. Scale bars: A-D, 1 mm; E-H, 200 μm.