A systematic review of “ Asthenotoma spiralis (Smith, 1872) ” in West Africa, with description of two new species (Mollusca, Gastropoda, Conoidea)
Author
Gofas, Serge
Universidad de Málaga, Departamento de Biologia Animal, Facultad de Ciencias, E- 29071 Málaga (Spain) sgofas @ uma. es
sgofas@uma.es
Author
Rolán, Emilio
Museo de Historia Natural, Campus Universitario Sur, E- 15782 Santiago de Compostela (Spain) erolan @ emiliorolan. com
text
Zoosystema
2009
2009-03-31
31
1
5
16
http://www.bioone.org/doi/abs/10.5252/z2009n1a1
journal article
10.5252/z2009n1a1
1638-9387
5393225
Tomopleura fuscocincta
n. sp.
(
Figs 7
;
8
;
10B
;
11B
)
Asthenotoma spiralis
–
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
)
].
TYPE MATERIAL
. —
Holotype
(spm, 11.3 ×
3.6 mm
,
MNHN 21408
) (
Fig. 7A, B
);
10 paratypes
from the type locality (5
MNHN 21409
,
5
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.
FIG. 7.—
Tomopleura fuscocincta
n.sp.
:
A
,
B
, holotype (spm,height 11.3 mm),off Ilha de Luanda,Angola,40-60 m (MNHN);
C
,
D
, paratype (sh, height 11.5 mm), same locality (MHNS);
E
,
F
, specimen from off Dakar, Senegal (height 15.3 mm, MNHN).
DESCRIPTION
Shell slender, fusiform with a high conical spire. Protoconch (
Fig. 10B
) 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
) 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
.