Rissoidae (Mollusca: Gastropoda) from northeast Atlantic seamounts
Author
Gofas, Serge
text
Journal of Natural History
2007
2007-06-04
41
13 - 16
779
885
http://dx.doi.org/10.1080/00222930701298085
journal article
10.1080/00222930701298085
1464-5262
5229647
Gofasia vanderlandi
Bouchet and Warén, 1993
(
Figures 34
,
35
)
Gofasia vanderlandi
Bouchet and Warén 1993
, p 668
–670.
Type material
Holotype
(1.68×
1.09 mm
) from CANCAP sta. 3068, in
RMNH
;
seven paratypes
in
MNHN
(1.36×0.96 to 1.78×
1.16 mm
) and in
SMNH
.
Type locality
Off
Canary Islands
(30
°
079N, 15
°
539W,
310 m
)
.
Material examined
Ampère—
Seamount 1
sta. CP99, 6 sh. (1.16×0.76 to 1.44×
0.96 mm
) examined by
Bouchet and Warén (1993)
; 3 spm. (jv. 1.02×
0.72 mm
; 1.40×
0.84 mm
; 1.45×
0.86 mm
)
Figure 34.
Gofasia vanderlandi
Bouchet and Warén, 1993
. (A, B) Specimen from Ampère seamount, CP99 (225– 280 m), actual size 1.45 mm; (C) protoconch of a juvenile shell, same locality; (D) microsculpture, same shell as (C). Scale bars: 100 Mm (C); 50 Mm (D).
and 5 sh. (1.18×0.80 to 1.40×
0.94 mm
);
Victor Hensen
VH
97 sta. 97, 5 sh. (1.16×0.82 to 1.48×
0.94 mm
).
Description
Shell with a moderately high spire and a blunt apex, rather thin, adults up to 1.5×1.0 mm. Protoconch of 1.25 convex whorls; surface of larval whorls covered by minute granules arranged in blurry spiral bands. Teleoconch of 2.25–2.75 convex whorls, with a very faint sculpture of axial lines or poorly defined, fine axial folds, extremely minute spiral lines of pores and very faint spiral cords restricted to the abapical area. Axial lines or folds irregular, parallel to growth stages, too poorly defined to be considered ribs, very gradually fading out on the abapical part of the body whorl. Spiral cords very low and faint, as broad as the interspaces, developed only on the periumbilical area of the body whorl; a very faint depression running subsuturally. Spiral rows of pores visible only at high magnification, accompanied by a few spiral threads in the subsutural area. Outer lip orthocline, with a thin edge and slightly thickened externally at a distance of the edge, smooth and not thickened inside. Inner lip thin, bordering a narrow umbilical chink. Shell colour entirely white, translucent. Operculum thin, paucispiral, with eccentric nucleus.
Figure 35.
Gofasia vanderlandi
Bouchet and Warén, 1993
. (A) Living specimen from Ampère seamount, CP99 (225–280 m), same as Figure 34A, B, actual size 1.45 mm; (B) detail of head and propodium; (C) detail of opercular lobes and metapodium.
Cephalic tentacles cylindrical, with rounded tips. Eyes embedded in a slight swelling at the base of each tentacle. Snout somewhat tapering, truncated and bilobed anteriorly, with tiny bright yellow jaws visible by transparency and anterior part tinged with pale brown. Small, whitish granular masses behind each eye; other more irregular whitish mass visible by transparency beneath the operculum. Sole of foot colourless with pedal glands inconspicuous; metapodium with a faint longitudinal groove. One metapodial tentacle, forming a triangular flap. Right and left pallial tentacles tiny. Visceral mass visible by transparency in the spire whorls, reddish brown with series of black granules.
Remarks
The above description is based on specimens from Ampère seamount. Part of the material studied here was cited by
Bouchet & Warén (1993
, p 667–670) as representative of their
Gofasia vanderlandi
, and specimens from Ampère sta. CP99 were figured (their Figures 1533, 1537). The
type
specimens (
Bouchet & Warén, 1993
, Figures 1540, 1542–1544) were collected off the
Canary Islands
and differ in having a lower spire with more conspicuous axial folds. It is not proved that the seamount specimens are conspecific but, in view of the scanty material at hand, I will respect Bouchet and Warén’s taxonomic placement.
This species resembles, due to its very faint sculpture,
Pseudosetia amydralox
. However, the microsculpture of the protoconch with spiral threads is definitely different in
Pseudosetia
; furthermore the latter do not have a pitted microsculpture on the teleoconch.