Gofasia vanderlandi Bouchet and Warén, 1993

Gofas, Serge, 2007, Rissoidae (Mollusca: Gastropoda) from northeast Atlantic seamounts, Journal of Natural History 41 (13 - 16), pp. 779-885 : 835-837

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)

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.

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.

Figures

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).

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.