Alvania xelae Oliver & Urgorri, 2022

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 : 23

Alvania xelae Oliver & Urgorri sp. nov.

( Fig. 14 )

Alvania electa — Bouchet &Warén, 1993: 663–636 (in part), figs. 1416–1417.

Type material. Holotype: SPAIN • 1 emPty shell ( Figs. 14d–h ); 43° 57.030′N, 008° 54.795′W to 43° 57.248′N, 008° 54.133′W; 1191– 1132 m; 08–15 SeP. 2002; DIVA-Artabria I AT-1000 ; MHNS, dePosit number: MHN-USC-10117 . Paratypes: SPAIN • 2 sh (ParatyPes 1 and 2); 43° 51.265′N, 008° 54.480′W to 43° 51.498′N, 008° 53.123′W; 827– 819 m; 08–15 Sep. 2002; DIVA-Artabria I DRN-800 ; MNCN 15.05 /200227 • 1 sh; 43° 52.823′N, 008° 56.151′W to 43° 52.837′N, 008° 55.597′W; 988– 920 m; 08–15 SeP. 2002; DIVA-Artabria I DRN-1000 • 2 sh; 43° 47.188′N, 008° 53.053′W to 43° 55.312′N, 008° 53.101′W; 770–842 m; 08–15 SeP. 2002; DIVA-Artabria I AT-800 • 1 spc + 22 sh; 43° 57.030′N, 008° 54.795′W to 43° 57.248′N, 008° 54.133′W; 1191– 1132 m; 08–15 SeP. 2002; DIVA-Artabria I AT-1000 • 1 sPc + 1 sh; 43° 53.575′N, 008° 56.868′W to 43° 54.015′N, 008° 56.959′W; 965–974 m; 10–20 SeP. 2003; DIVA-Artabria I DRN-1000 • 12 sPc + 3 sh; 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 • 12 sh; 43° 51.873′N, 008° 53.683′W to 43° 53.120′N, 008° 53.301′W; 802– 788 m; 10–20 SeP. 2003; DIVA-Artabria I EBS-800 • 1 sh; 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; 720 m; SARRIDAL (2006–2007) SARRI-1 • 14 sh; 44° 11.652′N, 008° 58.152′W to 44° 11.539′N, 008° 57.574′W; 908–1106 m; 15–24 Jul. 2008; A SELVA DRN-7 • 2 sh; 44° 08.65′N, 008° 55.305′W to 44° 08.771′N, 008° 55.104′W; 581– 566 m; 15–24 Jul. 2008; A SELVA DRN-7 C • 1 sh; 43° 34.86′N, 009° 21.95′W to 43° 36.44′N, 009° 20.71′W; 1010–1112 m; 15–30 SeP. 2008; DIVA-Artabria II EBS-04 .

Type locality: Ferrol Canyon off Galicia coast (43° 57.030′- 43° 57.248′N, 008° 54.795′W- 00854.133′W, 1132–1191 m) .

Derivatio nominis: This species is dedicated to Dra. Xela Cunha Veira who has participated in the collection of samples in all oceanographic campaigns and for the custody and handling of the samples studied.

Description. Shell with a moderately high sPire with conical outline, aPical angle of about 45° and a blunt aPex, somewhat solid, with conspicuous reticulated sculpture ( Fig. 14a ). Holotype ( Fig. 14d ) of 1.6 x 1.0 mm with four convex whorls. Adult shells studied up to 1.7 x 1.2 mm. Well-marked, somewhat channeled suture. Colour white. Aperture pyriform, pointed at union with penultimate whorl, height 0.56 mm (about 46% of total height). Umbilical area with chink and coarse growth lines. About 20 sharP, orthocline axial ribs, at about 10° with sPire axis, narrower than interspaces on the body whorl and disappearing toward the base. Thick spiral cords, also narrower than interspaces, more developed on the periumbilical area of the body whorl. Entire surface covered by regularly distributed spiral threads, much narrower than their interspaces, often interrupted where crossing growth lines ( Fig. 14e ). Outer lip slightly opisthocline with a thin edge, thickened externally and not thickened inside. Inner lip thin, bordering a narrow umbilicus.

Radulae, operculum and soft parts have not been described since they show great uniformity in species of this genus. Specimens are kept for possible future studies.

Protoconch of 1.25 convex whorls ( Figs. 14g –h ) whose surface is covered by minute granules irregularly arranged ( Fig. 14c ) overlapping wide, diffuse spiral cords ( Fig. 14b ).

Remarks. About 75 shells and specimens were found in 10 samples collected between 400 and 1200 m. Most of the shells with soft parts were found in a sample at around 600 m depth in sandy bottom. No notable variability was observed.

Alvania xelae sp. nov. has been believed to fall within the variability of A. electa , and corresponds to one of the shells illustrated under that name by Bouchet & Warén (1993, figs. 1416–1417 from THALASSA st X362 at 385–600 m off north Spain coasts). Alvania xelae sp. nov. differs from A. electa by its more convex whorls, not so deeply channelled suture and especially by its protoconch with wide diffuse spiral cords ( Fig. 14b ) instead of fine striae ( Figs. 9b–c ). This sculpture of the protoconch also differentiates it from the other species of the group of A. electa ( A. porcupinae , A. adinogramma , A. cancapae and A. candasae sp. nov.). On the other hand, A. seinensis from the Seine seamount has a shell protoconch similar to that of the new species but its teleoconch has much finer and more numerous ribs (more than 40 on the penultimate whorl) and a less marked spiral sculpture ( Gofas 2007, fig. 7E–F).

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 14. Alvania xelae Oliver & Urgorri sp. nov. a–c One of the paratypes (DA-I(02): DRN-800). a Shell (1.2mm); b–c Protoconch and details of its microsculpture. d–h Holotype (DA-I(02) AT-1000). d Shell (1.6 mm); e Details of the microsculpture of the teleoconch; f Detail of the transition protoconch/teleoconch; g–h Lateral and apical views of the protoconch.