Cominella alertae (Dell 1956)

“Fax alertae n.sp. Fig. 133.

Shell of medium size, rather solid, body whorl inflated. Spire less than height of aperture, turreted. Whorls 4 to 5 plus protoconch of 2 whorls. About 100 specimens were obtained, but all are chalky and somewhat worn on the apex. Protoconch, however, is dome-shaped and large, apparently originally with glossy surface, terminating with a number of closely spaced axials. Early sculpture of raised axial folds. A shoulder is soon formed high up on the whorl, and the axials then are raised into small, rounded nodules on the angle. Shoulder at first almost horizontal, but it gradually slopes as the whorl angulation is lowered. Angula­tion much less marked on the body whorl and the shoulder markedly concave. Spire whorls with raised, vertical, axial folds extending from the angula­tion to the lower suture, and curving as much reduced folds across the shoulder to the upper suture, gradually disappearing about the sutural level on the body whorl. They also tend to become obsolete across the last quarter of the body whorl. Shoulder with some six low, but rather broad, spiral cords which run across the axial threads. Spire whorls with some 5 or 6 finely incised spirals running round the whorl below the angulation. On the upper spire whorls the uppermost of these spirals runs just below the angulation, and accentuates the nodulations. This effect disappears across the penultimate whorl. Spirals increase on the body whorl, become obsolete medially, but are well marked on the base, some 16 being present across the body whorl and base.

Aperture constricted above by the concave shoulder, outer lip slightly thickened with a shallow broad posterior sinus. Inner lip with moderate thickening, slightly separated from parietal wall in some specimens. Fasciole prominent, marked off by a ridge. Fasciole surface drawn into a sharp median fold, portion between this fold and the demarcating ridge hollowed out, sculptured with close-spaced growth lines and fine spirals. Colour white, with thin pale brown epidermis.

Height, 27.7 mm.; diameter, 12.5 mm. (holotype).

Holotype (M. 9773) and many paratypes in Dominion Museum, many para­types in Canterbury Museum.

Localities: C.I.E. Station 6, Chatham Rise, in 220 fathoms (type); C.I.E. Station 7, Chatham Rise, in 280 fathoms; C.I.E. Station 40, south-east of Pitt Island, in 155 fathoms; C.I.E. Station 41, south-east of Pitt Island, in 330 fathoms; C.I.E. Station 52, Chatham Rise, in 260 fathoms; C.I.E. Station 58, Chatham Rise, in 320 fathoms; C.I.E. Station 59, Chatham Rise, in 290 fathoms; C.I.E. Station 5, Chatham Rise, in 300 fathoms.

Radula (Fig. B, 14), with a tricuspid central and a bicuspid lateral on each side. Base of central wide and arched, bearing three equally developed cusps, which in some specimens are reinforced by a central thickened support. Laterals with two strong cusps. In some specimens the arrangement of the cusps on the centrals is less regular. All have three subequal primary cusps, but a subsidiary cusp may be developed outside these, either on one side or both.”

(Dell, 1956: 92-93)

Cominella alertae is a species of predatory deepwater sea snail, a marine gastropod mollusc in the family Cominellidae.