Laevilitorina magellanica González-Wevar & Rosenfeld

Rosenfeld, Sebastián, Segovia, Nicolás I, Maturana, Claudia S, Aldea, Cristián, Saucède, Thomas, Brickle, Paul, Spencer, Hamish G, Poulin, Elie & González-Wevar, Claudio A, 2023, A revision of the higher latitude periwinkle species Laevilitorina caliginosa sensu lato, Zoological Journal of the Linnean Society 202 (1), pp. 1-18 : 3-6

Laevilitorina magellanica González-Wevar & Rosenfeld sp.nov.

( Fig. 2 )

Laevilitorina caliginosa – Ríos and Gerdes 1997: 51; Mutschke et al. 1998: 13; Ingólfsson 2005: 176; Rosenfeld et al. 2018: 9.

Laevilitorina caliginosa L1 – González-Wevar et al. 2022: 1527.

-75 -70 -65 -60 -55 Longitude

Zoobank registration: zoobank.org:act:BF37AA2E-2ADB-45F9-8EDA-6EAEA4B479A5.

Holotype: MNHNCL MOL-205424 , ~ 25 km north of Punta Arenas (− 52.987406°S, − 70.812342°W), Strait of Magellan, Chile, 21 June 2015, collected by Claudio González-Wevar and Sebastián Rosenfeld .

Paratypes: MNHNCL MOL-205425 ; MNHNCL MOL-205426 ; MNHNCL MOL-205427 ; MNHNCL MOL-205428 .

Description

Shell: Small (maximum height 4.03 mm), typical Laevilitorina morphology: fusiform with rounded to almost straight whorls, suture impressed, concave spire profile, apex blunt. Aperture rounded, slightly ovoid and ≤ 54% of total H ( Fig. 2A–C ). Macroscopic spiral and axial sculpture absent. Multiple fine growth lines over whole shell. Columella smooth, inner lip barely reflected over narrow and shallow umbilicus; outer lip thin, simple; no evidence of thickening. Colour variable: reddish to dark or olive brown, often with small white spots, irregular in size and position. Operculum corneous. Mature H 3.01– 4.06 mm (H/B = 1.25–1.53, SH = 1.77–2.01) (Supporting Information, Table S1).

External anatomy: Ventral area of foot orange, cephalic area black.

Radula: Rachidian: seven cusps, central cusp rounded, longest, in some cases with small denticles at end ( Fig. 2D ). First pair of flanking cusps pointed, about half size of central cusp; outer cusps smaller, also pointed. Lateral: six or seven cusps, main cusp more rounded with denticulate end, accompanied by two pointed outer cusps and three or four inner ones ( Fig. 2E ). Inner marginal: six or seven cusps, pointed and of similar size, except for broader main cusp, which terminates with denticulate end ( Fig. 2F ). Outer marginal: nine thin and pointed cusps.

Holotype dimensions: Length 3.19 mm, width 2.34 mm.

Depositories: Holotype MNHNCL MOL-205424. Museo Nacional de Historia Natural, Chile.

Type locality: Chabunco (52°59 ʹ 14.66″S, 70°48 ʹ 44.43″W), Strait of Magellan, Chile ( Fig. 2G ).

Habitat: Rocky intertidal shores of the central micro-basin of the Strait of Magellan. Laevilitorina magellanica is commonly found in rock crevices, underneath boulders and/or also on the beds of the mytilid Perumytilus purpuratus (Lamarck, 1819) .

Materialstudied: FaroSanIsidro,StraitofMagellan(− 53.785572°S, − 70.973522°W), n = 30; Port Famine, Strait of Magellan (− 53.609464°S, − 70.931500°W), n = 80; Punta Carrera, Strait of Magellan (− 53.586367°S, − 70.923372°W), n = 50; Leñadura, Strait of Magellan (− 53.213428°S, − 70.938350°W), n = 50; Chabunco (− 52.987496°S, − 70.812342°W), n> 100; Possession Bay (− 52.232083°S, − 69.297419°W), n = 20 ( Fig. 2G ).

Etymology: The type locality of this species is the Strait of Magellan.

Remarks: In general, owing to the significant morphological plasticity recorded in the nominal species L. caliginosa ( Reid 1989; Engl 2012), this new species was previously reported from the Strait of Magellan as L. caliginosa . Nevertheless, in terms of morphology, this new Laevilitorina species is characterized by its small size. In contrast to L. caliginosa and L. fueguina , which exceed 5 mm in shell height, the maximum size of L. magellanica does not exceed 4.10 mm. Moreover, L. magellanica differs from L. fueguina by having a larger spire size and slightly more convex whorls and differs from L. caliginosa by having a larger aperture length. Moreover, L. magellanica differs from other Antarctic and sub-Antarctic Laevilitorina in having denticles on the main cusps of the lateral and inner marginal teeth ( Fig. 2E, F ).

Figures

Figure 2. Laevilitorina magellanica, Chabunco, Strait of Magellan, southern South America. Scale bars: 1 mm unless specified otherwise. A–C, shell morphology and coloration of L. magellanica in the Strait of Magellan.D–F, radular morphology (SEM), showing a general view (D), lateral view (E), and inner marginal showing denticles (white arrows; F). G, distribution of L. magellanica in the Strait of Magellan.