Naudedrillia hayesi Kilburn, 2005

Kilburn, Richard N., 2005, New species of Drilliidae and Turridae from southern Africa (Mollusca: Gastropoda: Conoidea), African Invertebrates 46, pp. 85-92 : 90-92

Naudedrillia hayesi Kilburn , sp. n.

Figs 7–9

Etymology: Named in honour of Brian Hayes of Port Elizabeth, who kindly provided the type material.

Description: Shell claviform (b/l 0.33–0.37, a/l 0.31–0.37), spire more or less orthoconoid, apex somewhat papilliform, siphonal canal moderately long for genus, strongly tapering, end obliquely truncate; suture fairly shallow, not undulating; teleoconch whorls about 9; early whorls with a distinct shoulder, later ones slightly or not angular, periphery at or above midwhorl, subsutural region not swollen nor forming a cord, subsutural region weakly concave, occupying about 0.3 of whorl; left side of base of body whorl

7 8 9

weakly concave, fasciole absent, without false umbilicus.Aperture oblong-ovate, slightly trigonal, not patulous anteriorly, siphonal canal short, very wide, oblique, termination not indented dorsally; columella callus thin, parietal pad fairly weak, barely constricting entrance to anal sinus; outer lip thin, slightly incurved, smooth, stromboid notch distinct, anal sinus deep, linguiform, directed slightly basally, occupying shoulder slope.

Sculpture of weak axial ribs (stronger on early whorls), spiral sculpture of fine threads, mainly restricted to base; growth-lines irregular but thread-like, usually faint in peripheral region, except under suture where they are very fine and regular; no terminal varix although axial ribs are well-developed behind outer lip.Axial ribs strongest at periphery, evanescing at subsutural concavity and at lower suture, on body whorl at level of parietal pad, becoming stronger and reaching base on back of body whorl, somewhat arcuate, opisthocline, in t/s low, rounded, more or less equal to intervals, but on later whorls weak to obsolete; 14–16 on penultimate whorl, eroded on early whorls. Spiral sculpture restricted to base of last whorl, from mid-columella anteriorly, consisting of thin, low spiral threads, rather irregular and rendered slightly granular by growth lines.

Colour light yellowish-brown, with a white band at periphery, weakly interrupted between ribs, protoconch white.

Protoconch pupiform, about two whorls, termination distinct, smooth; breadth 1.17 mm.

Dimensions: 32.8 x 11.1 mm (holotype); 32.9 x 10.8 mm and 25.4 x 8.9 mm (largest and smallest paratypes).

Operculum thick, unguiculate, with the nucleus prominently raised into a triangular beak, above the level of the adjacent external surface ( Fig. 9 ).

Comparison: N. hayesi sp. n. is the largest known species of the genus, being slightly larger than the more subtropical N. nealyoungi Kilburn, 1988 . It differs from that species in shape. From all described congeners, N. hayesi differs in one or more of the following characters: fasciole absent; base more acute; subsutural region concave; spiral sculpture restricted to base of last whorl. Protoconch resembling that of N. nealyoungi (see Kilburn 1988: textfig. 19). The raised ‘beak’ on the operculum is, as far as is known, unique in the genus.

Holotype: NMSA W2713 /T2019. SOUTH AFRICA: Agulhas Bank, off Cape St Francis (approx. 34°13'S: 24°50'E), 150 m, trawled.

Paratypes: Three specimens from type locality in collection B. Hayes.Additionally, two paratypes off coast of Cape Town , 150 m, trawled: one NMSA W2715 /T2021, one in collection B. Hayes .

Distribution: Agulhas Bank to west of Table Bay, 150 m.

Figures

Figs 7–9. Naudedrillia hayesi sp. n., holotype NMSA W2713/T2019; off Cape St Francis, Agulhas Bank, 150 m, 32.8 x 11.1 mm: (7) aperture view, (8) lateral view, (9) operculum, length 5.7 mm.