Alvania denseclathrata (Thiele, 1925) n. comb.

(Figs 2; 48)

Rissoa denseclathrata Thiele, 1925: 81, pl. 6, fig. 11.

TYPE MATERIAL. — Lectotype. South Africa • dd; Valdivia Stn 95; 34°51’0”S, 19°37’47”E; 80 m; ZMB/Ma.64984 (here designated). Paralectotypes. South Africa • 4 dd; Valdivia Stn 95; 34°51’0”S, 19°37’47”E; 80 m; ZMB/Ma.64984 • 3 dd; Valdivia Stn 104; 35°15’57”S, 22°26’42”E; 155 m; ZMB/Ma.64984 .

Angola • 2 dd; Valdivia Stn 81; 16°26’27”S, 11°41’27”E; ZMB/ Ma.64984 .

TYPE LOCALITY. — South Africa, Valdivia Stn 95; 34°51’0”S, 19°37’47”E; 80 m.

DISTRIBUTION. — Only known from southern Africa (Valdivia Stns 95 and 104) and from a station in southern Angola (Valdivia Stn 81) (Fig. 48).

DIAGNOSIS. — Alvania with small (height c. 2 mm), robust shell, ovate-conical; convex whorls with weakly impressed suture; axial and spiral double sculpture dense, of equal thickness; aperture piriform, peristome continuous and simple, outer lip with robust varix; umbilical fissure absent. Protoconch paucispiral, dome-shaped, with spiral sculpture. Colouration uniform whitish.

REMARKS

The lot from southern Angola (Valdivia Stn 81) comes form a completely distinct biogeographic area, and we are not sure it is not a case of mislabelling. In any case, to stabilize the type locality we have designated as lectotype a specimen from the Cape area (Valdivia St. 95). Rissoa denseclathrata is currently included (Ponder 1985) in Haurakia Iredale, 1915 . However, this is clearly a member of Alvania, with its shell devoid of umbilical fissure, with double sculpture (axial and spiral), piriform aperture, continuous and simple peristome, outer lip with robust varix, dome-shaped paucispiral protoconch with spiral sculpture. Alvania valeriae Absãlao, 1993 from off southeastern Espirito Santo State (southeastern Brazil) 38 m depth (Absãlao 1993: 104, 105, figs 1-3; Oliveira et al. 2018: 95, fig. 4 I-K), differs from Alvania denseclathrata n. comb. in its protoconch (quite evidently paucispiral and not multispiral as originally described) without sculpture vs sculptured with spiral cordlets in A. denseclathrata n. comb.; in the narrow umbilical fissure, absent in A. denseclathrata n. comb.; in the absence of a labial varix vs a robust labial varix in A. denseclathrata n. comb.

Alvania flexilis Gofas, 1999 from off Ilha de Luanda (Angola) 40-60 m (Gofas, 1999: 85, figs 27-32), differs from A. denseclathrata (Thiele, 1925) n. comb., in its multispiral protoconch sculptured with granules vs paucispiral with spiral sculpture in A. denseclathrata n. comb.; in the axial and spiral sulpture on the teleoconch more spaced than in A. denseclathrata n. comb.

We accordingly propose Alvania denseclathrata (Thiele, 1925) n. comb. as a new combination for Rissoa denseclathrata Thiele, 1925 .