Tomopleura fuscocincta, Gofas & Rolán, 2009

Gofas, Serge & Rolán, Emilio, 2009, A systematic review of “ Asthenotoma spiralis (Smith, 1872) ” in West Africa, with description of two new species (Mollusca, Gastropoda, Conoidea), Zoosystema 31 (1), pp. 5-16 : 11-13

publication ID	https://doi.org/ 10.5252/z2009n1a1
DOI	https://doi.org/10.5281/zenodo.5469357
persistent identifier	https://treatment.plazi.org/id/03CC3008-FF92-FF8A-30C7-FB0175041DC8
treatment provided by	Marcus
scientific name	Tomopleura fuscocincta
status	sp. nov.

Treatment

Tomopleura fuscocincta View in CoL n. sp.

( Figs 7 View FIG ; 8 View FIG ; 10B View FIG ; 11B View FIG )

Asthenotoma spiralis View in CoL – Ardovini & Cossignani 2004: 219, 220 (unnumbered figure of specimens from Mauritania, but not specimens from Senegal and Gabon on page 220) [non A. spiralis ( Smith, 1872) View in CoL ].

TYPE MATERIAL. — Holotype (spm, 11.3 × 3.6 mm, MNHN 21408 About MNHN ) ( Fig. 7A, B View FIG ); 10 paratypes from the type locality (5 MNHN 21409 About MNHN , 5 About MNHN MHNS).

TYPE LOCALITY. — Off Ilha de Luanda, Angola (08°44’S, 13°12’E, 40-60 m) on bottom of bioclastic sand with rocks.

ETYMOLOGY. — The name alludes to the darker hue of the cords, contrasting with the other species.

MATERIAL EXAMINED. — Mauritania. RV N’Diago stn 118, 18°35.94’N, 16°30.48’W, 96 m, 1 sh (10.0 × 3.7 mm). — RV N’Diago stn 153, 18°18’N, 16°28’W, 90 m, 1 sh (9.9 × 3.4 mm). — RV N’Diago stn 246, 17°54’N, 16°26’W, 108 m, 1 sh (12.5 × 4.2 mm). — RV Meteor stn 60-77, 17°17’N, 16°30’W, 85 m, 2 sh (15.3 × 4.6, 15.7 × 5.0 mm).

Senegal. Dakar area stn 58.2.4B, 12°56’N, 17°26’W, 43 m, leg. Marche-Marchad, 1 sh (15.0 × 4.5 mm). — Baie de Rufisque, 10-20 m, leg. Pin, 1987, 1 spm (15.3 × 4.7 mm).

Ghana. Calypso stn 25, 04°36’N, 01°31’W, 50 m, 6 sh (8.1 × 3.1 to 12.4 × 3.7 mm). — Off Adjua, 40 m, 2 spm (9.4 × 2.9, 10.0 × 3.1 mm, MHNS ex collection Peter Ryall).

Gabon. Port Gentil, “N’Kondo” oilfield, leg. Chevallier, 1 sh (8.1 × 2.9 mm). — Port Gentil, “Anguille” oilfield, leg. Chevallier, 1 sh (11.0 × 3.2 mm).

Angola. Off Ilha de Luanda, 08°44’S, 13°12’E, 40-60 m, 14 spm (5.0 × 2.0 to 14.0 × 4.1 mm) and 22 sh (5.5 × 2.2 to 14.2 × 4.3 mm) [includes types]. — Idem, 1 spm (11.7 × 3.9 mm, MHNS), 22 sh (8.0 × 2.7 to 14.9 × 4.8 mm, MHNS), 6 j. — Luanda, 2 sh, 2 j ( MHNS). — Luanda, 35-40 m, 1 spm ( MHNS). — Luanda, Matuco, 20 m, 10 sh (9.0 × 2.9 to 14.8 × 4.9 mm, MHNS), 1 j. — Off Ilha de Luanda, 100 m, 4 sh (9.2 × 3.0 mm, MHNS), 15 j. — Off Ilha de Luanda, 120 m, 4 sh (8.0 × 3.0 to 10.8 × 3.4 mm). — Idem, 1 sh ( MHNS). — Corimba, 08°51.4’S, 13°10.0’E, 20 m, 1 j ( MHNS). — Off Mussulo, 08°51’S, 13°00’E, 90 m, 10 sh (1.7 × 0.8 to 11.4 × 3.7 mm). — Off Mussulo, Macôco, 50-70 m, 1 spm (12.3 × 3.7 mm) and 4 sh (4.7 × 1.9 to 10.5 × 3.5 mm). — Cape Palmeirinhas, 60-80 m, 5 sh (8.0 × 2.8 to 9.8 × 3.3 mm). — Idem, 20 m, 1 sh (6.5 × 2.3 mm, MHNS), 6 j.

DESCRIPTION

Shell slender, fusiform with a high conical spire. Protoconch ( Fig. 10B View FIG ) of c. 3 smooth, convex whorls, the last one with abapically a narrow keel coincident with the suture, with diameter of nucleus 250 µm and maximum diameter 480 µm; transition to teleoconch with a few narrow riblets which start nearly axial in their adapical part, then are markedly curved to follow the contour of the “sinusigera” aperture of the larval shell.Teleoconch of 7-9 whorls, with a strong spiral sculpture. Sculpture on spire whorls starting with one subsutural keel and another prominent keel on the abapical part of the first whorl, separated by a flat area where a smaller intermediate spiral cord is present; sculpture continued on later spire whorls with the stronger keel shifting towards the median part of the whorls, and a third cord being revealed on the abapical edge of the whorl, partly concealed by the subsequent whorl; the adapical intermediate cord becoming more tenuous and eventually reduced to one or several spiral threads; on later whorls with one or two additional threads abapically to the main keel.Body whorl with several additional acute cords abapically to the main keel, decreasing in size towards the abapical end. Furrows between spirals concave, crossed by well-defined axial riblets running parallel to the growth lines.

Aperture devoid of parietal callus on the columellar side. Siphonal canal short and broadly open; adapical end of the aperture narrowing to a small notch reaching the suture. Outer lip simple, with a marked U-shaped notch situated adapically to the termination of the major keel, at a short distance from the suture, then with a convex profile as seen from one side. Colour of shell whitish or creamish with darker, brownish to purplish cords; abapical end of shell also darker.

Living animal ( Fig. 8 View FIG ) as in T. spiralissima but with uniform, very pale buff colour of the headfoot, without flecks; siphon whitish with very few yellow flecks.

HABITAT

On the continental shelf (usually 50-100 m) on current-swept bottoms with bioclastic rubble and rocky outcrops.

REMARKS

This species is broadly sympatric with T. spiralissima but occurs deeper, on a quite different kind of bottoms, and avoids the muddy sites where the latter is usually found. The columella is not dark brown. Contrary to the other species which tend to be uniform in colour or have paler cords, this species has distinctly darker spirals on a pale background, particularly conspicuous on fresh specimens. Colour however tends to fade after some years even if shells are preserved from sunlight. The protoconch is also distinct, having one whorl less and a distinct suprasutural cord; on the teleoconch the axial riblets between keels are much more conspicuous and widely spaced, and the additional cords on spire whorls are usually not developed in T. spiralissima .