Lanayrella vagabunda ( Mabille, 1885 ) Salvador & Cunha, 2020

Salvador, Rodrigo B. & Cunha, Carlo, 2020, Lanayrella, a new Acteonidae genus (Gastropoda, Heterobranchia) from Tierra del Fuego, Journal of Natural History 54 (15 - 16), pp. 1009-1018 : 1011-1014

Lanayrella vagabunda ( Mabille, 1885) comb. nov. ( Figure 1 )

Tornatella vagabunda Mabille, 1885: 208 ; Rochebrune and Mabille 1889: 12–14, pl. 6, figs. 2a–b; Valdés and Héros 1998: 698, fig. 1C. Acteon vagabunda: Pilsbry 1894: 164 , pl. 18, 95–96. Acteon vagabundus: Thiele 1912: 265 ; Linse 1999: 403; Forcelli 2000: 116. ‘ Acteon ’ vagabundus: Castellanos et al. 1993: 8 , figs 5–6. Toledonia vagabunda: Rosenberg 2009 [in part]; Forcelli and Narosky 2015: pl. 7, fig. 18.

Type locality

Chile: Magallanes Province, Cape Horn. ‘ In insulis Magellanicis (de la Mission au Cap Horn, 1882–1883)’ ( Rochebrune and Mabille 1889).

Type material

Syntype MNHN-IM-2000-23191.

Diagnosis

Whorls and spire proportionately taller than in L. ringei ; shell wall thinner; aperture more elongated. Teleoconch sculptured by more numerous punctate spiral grooves, closely packed together; punctae rectangular, large and well defined throughout the entire shell.

Redescription

Shell elongated, last whorl with a slightly rounded profile, imperforate; D/H 0.49–0.52. Spire with slightly rounded whorls and faintly step-like profile; suture distinctly marked. Colour light brown. Protoconch indistinct, nucleus fully immersed ( Figure 1 (g)); first whorl width 0.42 mm. Teleoconch with 4.5 whorls, entirely sculptured by narrow punctuated spiral grooves (~26 grooves on last whorl), separated from each other by a distance of unsculptured shell of roughly the width of each groove (0.14 mm); grooves become more numerous in later whorls and are more closely packed together towards umbilicus ( Figure 1 (c)). Grooves composed of small rounded-rectangular punctae, partially fused to next one within each groove, but still individually distinct ( Figure 1 (f)). Aperture anteriorly rounded, slightly narrowed posteriorly; h/H 0.70; parietal region 0.5 h, with thin welldelimited callus; columellar region broad, slightly expanded, with a sharp edge, bearing a thickened adapical fold; outer lip sharp, thickened externally.

Measurements

Syntype: H = 8.2 mm, D = 4.3 mm, S = 2.5 mm, h = 5.7 mm, d = 2.6 mm.

Distribution

Tierra del Fuego, Cape Horn. Literature data: Magellan region ( Linse 1999: defined as the Patagonian shelf south of ca. 41°S on both Pacific and Atlantic sides, including the Falkland Islands / Islas Malvinas); or 55– 56°S 65– 68°W ( Castellanos et al. 1993; Rosenberg 2009; Rosennfeld and Aldea 2011). Depth: 10 m ( Rosenberg 2009; Rosennfeld and Aldea 2011).

Figures

Figure 1. Lanayrella vagabunda, syntype; H = 8.2 mm. A. Apertural view. B. Dorsal view. C. Apertural view, under SEM. D. Detail of spire top showing teleoconch sculpture. E. Apical view, under SEM. F. Detail of body whorl showing teleoconch sculpture under SEM. G. Detail of spire top, under SEM, showing fully immersed protoconch. Scale bar = 200 μm.