Small, but relatively large for genus; elevated-turbiniform (L/D=l .0-1.25); teleoconch of 4.5-5.0 whorls; sculpture initially strongly cancellate, becoming foveolate with growth; spire truncate and protoconch sunken; first teleoconch whorl initially sculptured only by rib-like axial pliculae, but 3 spiral cords develop soon thereafter, one forming shoulder, another level with the abapical suture and the third between these at whorl periphery; cords and pliculae thickening considerably during third whorl and becoming less well defined; intermediary cords absent, with the exception of a fourth cord which usually develops on shoulder during third teleoconch whorl; intervals between cords wider than cords themselves; cords and pliculae interact to produce low conical granules where they cross; last adult whorl with 15-20 pliculae, those behind outer lip usually poorly defined or obsolete; pliculae narrower than cords on early whorls, more or less equal to them on last adult whorl; interstices distinctly quadrate apically, but becoming more rounded and pit-like (foveolate) on last adult whorl; strong growth flaws frequently present on last adult whorl. Base with 3 spiral cords, one level with suture, one marking edge of umbilicus and another between these; interval between outer and middle cords usually broader and with only weakly developed pits, that between middle and inner cords narrower and more strongly pitted; an additional cord is evident within umbilicus of young juveniles, but this becomes obscured with growth; umbilicus usually narrowly patent even in adults, occasionally closed; relatively wider in juveniles. Peristome oblique; aperture subcircular; columella concave with a broad rounded swelling at its base; swelling non-nacreous and rather variable in size; interior of aperture nacreous when fresh, lacking ridges or denticles inside outer lip. Microsculpture: Rather poorly defined and mostly covered by intritacalx deposit in fresh specimens; surface of apical whorls appearing etched, but with some traces of vermiform spiral threads; later whorls with close-set, shallow, prosocline, scratch-like marks. Protoconch: White; diameter ca 200 µm; sunken; apex very slightly pinched in; terminal lip with a well-developed trigonal projection; superficial sculpture well developed, arranged in irregular axial lines, spiral element scarcely evident. Colour: Fresh specimens milky-white with a relatively thick, chalky, white to pale buff or ashy-grey intritacalx deposit; deposit usually somewhat eroded. Dimensions: Holotype, length 7.6 mm, diameter 6.6 mm; largest specimen (NMSA S4006), length 8.65, diameter 6.9 mm. Operculum: Initially tightly multispiral, but whorls broadening with growth and becoming more openly multispiral.
Radula: Formula oo+3+1+3+oo; ca 45 transverse rows of teeth; transition from lateral to marginal series not well delineated. Rachidian with well-developed hood and narrowly trigonal cusp; cusp with small medial indentation near its base; cutting edge with a dominant, lanceolate central denticle, with 2 or 3 smaller denticles on each side. Only 3 lateral teeth evident, the fourth tooth is longer and lacks the robust, alate shaft of the laterals, and I consider it to be a marginal; lateral tooth cusps decreasing slightly in size from first to third, with a large, spathulate central element and smaller lateral denticles on both margins, those on the outer edge coarser. Marginals generally long and very slender, tending to collapse when air dried; inner ones somewhat shorter with a rather weakly and irregularly dentate, recurved cusp, and lacking well-developed pectinate denticles on its outer margin.

There is no similar species yet reported from the south-western Indian Ocean. V gemmula, V jayorum and V natalensis are much smaller and thinner shelled, lack a basal columella swelling and retain sharply defined spirals and axials throughout. Although they may resemble juvenile V. cretaceus, they have a narrower umbilicus, more evenly spaced cords on the base and a less strongly truncated apex. Furthermore, in these small species the spiral cords are stronger in relation to the axial pliculae and more elevated than they are in V cretaceus. V semilugubris is also smaller than V cretaceus, has denticles inside the outer lip when fully mature and is typically patterned with bold black markings.
This species differs from V angulatus (Pease, 1868) (type species of Vaceuchelus) and similar species from the south-western Pacific, such as V foveolatus (A. Adams, 1853) and V. scrobiculatus (Souverbie in Souverbie & Montrouzier, 1866), in being larger and in lacking denticles or ridges inside the outer lip (cf. figures provided by Herbert 1996). More similar to V cretaceus are V. cavernosus (Sowerby, 1905) from Sri Lanka and V clathratus (A. Adams, 1853) from the Philippines, both of which are of similar size and also lack sculpture inside the outer lip. Nonetheless, they retain a well defined, relatively fine, cancellate sculpture on the last adult whorl and have four and five spiral cords respectively on the base (including that level with suture) as opposed to three in V. cretaceus. Neither possesses the basal columella swelling of V cretaceus. The most similar species is the recently described Vaceuchelus pagoboorum Poppe, Tagaro & Dekker, 2006 from the Philippines. This is clearly closely related to V. cretaceus and likewise possesses a broad swelling at the base of the columella, but differs in having an additional low rounded tubercle inside the outer lip near its junction with the parietal portion of the aperture, has more evenly spaced basal cords (four in juveniles compared with three in V cretaceus, but the inner one becomes obsolete in adults), retains distinct pits in the interval between the out¬er and middle basal cords, and frequently has brownish markings on the spiral cords. With no material from intermediate localities, it is difficult to assess the significance of these differences, but they seem to constitute characters by which the populations can be distinguished and I thus describe the south-western Indian Ocean material as a new species.

Distribution and habitat: South-western Indian Ocean, known only from Reunion, southern Mozambique and northern Zululand (south to Mission Rocks); shallow subtidal to -250 m, but mostly shallower than -160 m (living specimens -50-70 m); dead shells not uncommon amongst lithothamnion encrusted pebbles and coral rubble in -50-70 m, beyond the near-shore reef system in northern Zululand.