Alvania electa ( Monterosato, 1874 )

Oliver, Joan Daniel, Gofas, Serge, Urgorri, Victoriano, Díaz-Agras, Guillermo & Templado, José, 2022, Rissoidae gastropods of the outer continental shelf and slope off Galicia (NW Spain), Zootaxa 5196 (1), pp. 1-45 : 17-18

Alvania electa ( Monterosato, 1874)

( Fig. 9 )

Material examined. (4 empty shells and 6 with soft parts, in 6 samples): SPAIN • 1 sPc; 43° 48.587′N, 008° 51.402′W to 43° 49.545′N, 008° 51.197′W; 610– 598 m; 10–20 SeP. 2003; DIVA-Artabria I EBS-600 • 2 sPc + 2 sh; 43° 36.544′N, 009° 03.064′W to 43° 36.816′N, 009° 04.339′W; 601–619 m; 17–28 SeP. 2004; VERTIDOS GA-EBS-600 • 1 spc; Polygon delimited by Points 44° 10.000′ N, 009° 00.000′ W /44° 10.000′ N, 008° 35.000′ W/44° 00.000′ N; 009° 00.000′ W/44° 07.000′ N; 008° 35.000′ W; 417–668 m; SARRIDAL (2006–2007) SARRI-4 • 1 sh; 44° 08.516′N, 008° 40.788′W to 44° 09.688′N, 008° 39.721′W; 436– 428 m; 15–24 Jul. 2008; A SELVA EBS-11 • 1 sPc + 1 sh; 44° 08.516′N, 008° 40.788′W to 44° 09.688′N, 008° 39.721′W; 436– 428 m; 15–24 Jul. 2008; A SELVA EBS-11-2 • 1 spc; 43° 48.252′N, 008° 51.427′W to 43° 49.707′N, 008° 51.164′W; 575–584 m; 15–24 Jul. 2008; A SELVA EBS-30-1 .

Remarks. This species has been recorded from the southern part of the Bay of Biscay to off the Canaries and Mediterranean Sea (where the type locality is located) in a wide depth range, normally in 150–800 m and occasionally deeper down to 2770 m ( Bouchet & Warén 1993). We have found six shells with soft parts and four empty shells in samples collected between 400 and 700 m in muddy sand bottoms.

Alvania electa is a rather variable species, as was pointed out by Bouchet & Warén (1993), and a cryptic species-complex may be involved. Its complex synonymy was unraveled by Oliverio et al. (1992). This species is characterized by its deeply channeled suture, low number of sharp axial ribs, narrow umbilical chink, and large and blunt apex ( Figs. 9a, d–f ). Protoconch sculpture with irregular microgranules separated by about six equidistant fine riblets ( Figs. 9b, c, g–i ).

The specimens here studied match with those figured by Gofas & Warén (1982, figs. 24 and 32 as Alvania deliciosa ( Jeffreys, 1884) , Oliverio et al. (1992, figs. 17–20) and Bouchet & Warén (1993, figs. 1412, 1415 and 1420).

In Figure 10 a–d we show for comparison a shell (as Alvania sp. ) from the Djibouti Bank (Alborán Sea) whose protoconch is like that of A. electa , but because its convex whorls and the higher number of axial ribs it resembles Alvania porcupinae Gofas & Warén, 1882 . On the other hand, the Mediterranean Alvania elegantissima ( Monterosato, 1875) has sometimes been confused with A. electa , but according to Oliverio et al. (1992) its convex whorls and protoconch without sculpture allow differentiate both species. Figure 10e–g shows a shell from off the Italian coast of the Tyrrhenian Sea that may be Alvania elegantissima by having opisthocline axial ribs and a protoconch lacking sculpture.

Figures

FIGURE 9. Alvania electa (Monterosato, 1874) (VE:GA-EBS-600). a Shell (1.8 mm); b–c Protoconch from a and detail of its microsculpture; d–e Details of microsculpture of the teleoconch of figure a; f Shell (1.7 mm); g–h Lateral view of the protoconch from f and detail of its microsculpture; i Apical view of another protoconch.

FIGURE 10. a–d Alvania sp. from Djibouti Bank (Alborán Sea). a Shell (1.8 mm); b–c Protoconch, lateral and apical view; d Detail of the protoconch/teleoconch transition. e–g Alvania cf. elegantissima off Italian coast of the Tyrrhenian Sea; e Shell (1.6 mm); f Apical view of the protoconch; g Detail of the axial ribs and spiral sculpture.