Alvania grancanariensis Segers, 1999

Amati, Bruno, Appolloni, Massimo, Giulio, Andrea Di, Scuderi, Danilo, Smriglio, Carlo & Oliverio, Marco, 2020, Revision of the Recent Alvania scabra (Philippi, 1844) complex (Mollusca, Gastropoda Rissoidae) from the Mediterranean Sea with the description of a new species, Zootaxa 4767 (3), pp. 415-458 : 453

Alvania grancanariensis Segers, 1999

( Figs 19 L–P; 17G–I)

Alvania grancanariensis Segers, 1999: 82 , figs 1–3

Other references.

Alvania grancanariensis ; Rolán et al., 2011: 130, figs 39E–G.

Type Material. Holotype KBIN.28739, type 484; paratypes: 53 sh (Segers coll.), 7 sh (Swinnen coll.), 15 sh (Zorn coll.), 4 sh ( ZMA), type locality: Maspalomas , Gran Canaria Is., Canary Islands.

Material examined. Canary Islands: Gando (Gran Canaria Is.), 48 m depth, 5 sh ( JT, JDO); Los Gigantes (Tenerife Is.), 10–35 m depth, xii.1994, 8 sh ( CS-PM).

Distribution. Canary Islands: Gran Canaria and Tenerife.

Remarks. This species was originally described as having a robust shell, bright orange-yellow protoconch and first teleoconch whorls, translucent pale whitish-yellowish last teleoconch whorls. However, specimens with monochrome whitish shells or with pale subsutural brownish blotches, and with the protoconch nucleus brown, are not rare. Furthermore, the material examined and the figures in Rolán et al. (2011: figs 39F, G) always show a spiral sculpture of four cords above the aperture (rarely 3), starting with two cords (not three as originally described). It is worth mentioning that the holotype of A. grancanariensis has two initial cords, whereas the specimen figured by Segers (1999: 82, fig. 2) with three cords was not part of the type material, and may belong to a different species. A. grancanariensis differ from A. canariensis in its lighter colour, with the first whorls of more or less intense orange; the dark spot on the protoconch nucleus, not marked; the more delicate sculpture on the teleoconch. It was sympatric with easily separable shells of A. canariensis .

Concluding remarks

We have revised the species of the Alvania scabra- complex with a focus on the Mediterranean Sea. Based on the scanty fossil record, the origin of this group seems younger than other lineages of Alvania (e.g. Alvania areolifera (Sandberger, 1863) (Garilli & Parrinello 2014) appearing in the Oligocene). We consider the following species to be valid: Alvania scabra ( Philippi, 1844) , Alvania sculptilis ( Monterosato, 1877) , Alvania sororcula Granata-Grillo, 1877 , Alvania lucinae Oberling, 1970 , Alvania josefoi Oliver & Templado, 2009 , Alvania scuderii Villari, 2017 and Alvania pizzinii n. sp. All species have paucispiral protoconchs indicating non-planktotrophic larval development. Only A. scabra has a wide range, spanning almost the entire Mediterranean (with some local gaps to be checked). All other species have seemingly restricted ranges, and all are sympatric with A. scabra ( Figs 3 , 8 , 10 , 13 ).

Figures

FIGURE 3. Distribution of Alvania scabra (Philippi, 1844), based on the material examined and checked literature data. Red dots, Recent records; blue dot, fossil records.

FIGURE 8. Distribution based on the material examined and checked literature data. Red dots, Alvania sculptilis (Monterosato, 1877). Light blue (Recent) and blue (fossil) dots, Alvania lucinae Oberling, 1970.

FIGURE 10. Distribution based on the material examined and checked literature data. Red dots, Alvania josefoi Oliver & Templado, 2009. Light-blue dots, Alvania sororcula (Granata-Grillo, 1877).

FIGURE 13. Distribution based on the material examined and checked literature data. Red dots, Alvania scuderii Villari, 2017. Light-blue dots, Alvania pizzinii n. sp.

FIGURE 19. Alvania spp. A, B. Alvania canariensis (d’Orbigny, 1840), Candelara la Caleta, Tenerife, Canary Island (Spain), height 2 mm (BA). C, D. Alvania sp. aff. canariensis (d’Orbigny, 1840), Gando Bay, Gran Canaria, Canary Islands (Spain), height 1. 85 mm (BA). E, F. Alvania canariensis (d’Orbigny, 1840), Monterosato coll. ex Mac Andrew coll., MCZR-M-30074, Canary Islands (Spain), height 1.8 mm with original label. G, H. Alvania angioyi vanAartsen, 1982, Biscoitos, Terceira (Azores), 1 m depth, height 1.7 mm (JT, JDO). I–K. Alvania sp., Monterosato coll. ex Mac Andrew coll., MCZR-M-30074, Azores, height 2 mm. L–P. Alvania grancanariensis Segers, 1999, Maspalomas, Gran Canaria, Canary Islands (Spain) height 1.7 mm (L: JT, JDO), 1.7 mm (M: JT, JDO), 1.85 mm (N–P: JT, JDO).