Alvania josefoi Oliver & Templado 2009

Alvania josefoi Oliver & Templado, 2009

(Figs 9 A–I; 14D–F; 10; 16G–I; Table VI)

Alvania josefoi Oliver & Templado, 2009: 64, figs 12–16, 23–24

Other references.

Alvania josefoi; Scaperrotta et al., 2019: 143, pl. IV, fig. D.

Type material. Holotype and nine paratypes (type locality) (MNCN, 1505/47058), type locality: South of Tagomago Is. (Ibiza, Baleares) (39°01’80’’N 01°39’14’’E).

Material examined. Balearic Islands: Punta de na Gall (Menorca Is.), 10 m depth, 25 sh (JT, JDO); Espardell Is. (Ibiza Is.), 25 m depth, 20 sh (JT, JDO).

Distribution. Balearic Islands (Fig. 10). Empty shells in bioclastic sands from 15–40 m depth (Oliver & Templado 2009), sympatric with A. scabra and A. sculptilis.

Description (in parentheses data for the holotype). Shell (Figs 9 A–I; 14D–F; 16G–I) small for the genus, height 1.20–1.83 (1.8) mm, width 0.73–1.05 (1.05) mm, H/W ratio 1.537 –1.743 (1.714), ovate-conic. Protoconch (Fig. 16H) paucispiral with nucleus moderately intorted, of 1.25-1.5 (1.45) whorls, height 0.25–0.312 (0.265) mm; nucleus diameter (d) 0.87–0.112 (0.90) mm, first half whorl diameter (Do) 0.20–0.212 (0.19) mm, maximum diameter (DM) 0.30–0.362 (0.335) mm, sculpture of ca. 10 parallel rows of closely-set rounded to broadly rounded (or triangular) microtubercles, sometimes fused (Fig. 16H). Protoconch/teleoconch boundary well marked. Teleoconch of 2.1–3.1 (3) convex, slightly angled whorls, with suture impressed. Axial sculpture on the last whorl of 18–32 (?) orthocline ribs plus labial varix, narrower than interspaces and interrupted at base. Spiral sculpture same strength as axial, of equidistant cords, 8–10 (9) on last whorl, with 4–5 (4) above aperture and 4–5 (5) on base. Cords II and IV starting immediately after protoconch-teleoconch boundary; cord I appearing at 1–1.5 whorls as a keel, gradually yet rapidly turning into a cord, cord III starting after 0.5–0.8 whorls (Table VI). Small, rounded tubercles at intersections; interspaces quadrangular. Microsculpture of growth lines and spiral threads overall (Figs 16H, I). Umbilical chink absent. Aperture pyriform, large, height 0.53–0.78 (0.78) mm, H/Ha ratio 2.182 –2.439 (2.31), peristome continuous, outer varix modest, internally smooth. Colouration monochrome white, with subsutural brown blotch on the outer varix, rarely extending toward the base. Operculum and soft parts unknown.

TABLE V. Measurements of teleoconch and protoconch of Alvania lucinae in mm, with range, mean and standard deviation. 1, 2, 5–7 = Golfo Aranci; 3, 4 = Giglio Is.

Remarks. Rather constant in shape and features: “Existe una gran uniformidad en todos los ejemplares estudiados, tanto en el tamaño, como en la forma y color.” (Oliver & Templado 2009: 64). About 20% of the specimens from Espardell Is. (Baleares) have cords II, III and IV starting after the protoconch/teleoconch boundary and cord I appearing at 1–1.5 whorls (Table VI). Few shells (2 out of 44 examined) show the subsutural brownish blotches typical of the A. scabra group, weaker than in the other species (Figs 14 D–F). Others lack even the blotch on the outer varix (19 shells out of 44 shells from Menorca and Ibiza, Baleares). See under A. scabra, A. sculptilis, A. sororcula, A. lucinae and A. pizzinii n. sp. for the differences with these species.

TABLE VI. Measurements of teleoconch and protoconch of Alvania josefoi in mm, with range, mean and standard deviation. 1–4, 6–9 = Menorca Is.; 5, 10–12 = Ibiza Is. 4 (shell with weak subsutural brown blotches). Specimens number 10, 11 and 12 have cords II, III and IV

A. josefoi differs from A. scuderii by its more numerous axials on the last whorl (19–32 in A. josefoi vs 15–18 in A. scuderii); the colouration (monochrome white, with the typical brown subsutural blotch before the varix in A. josefoi vs brownish background with dark brown spirals in A. scuderii).