Laevilitorina fueguina González-Wevar & Rosenfeld, 2023

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 : 6-8

Laevilitorina fueguina González-Wevar & Rosenfeld sp. nov.

( Fig. 3 )

Laevilitorina caliginosa L2 – González-Wevar et al. 2022: 1527.

Zoobank registration: zoobank.org:act: D3644473-71B7- 4D0E-B8B7-65DFC0761650.

Holotype: MNHNCL MOL-205434 , ~ 100 km south of Porvenir (− 53.313637°S, − 70.458217°W), Tierra del Fuego, Strait of Magellan, 22 May 2016, collected by Claudio González-Wevar and Sebastián Rosenfeld.

Paratypes: MNHNCL MOL-205435 ; MNHNCL MOL-205436 ; MNHNCL MOL-205437 ; MNHNCL MOL-205438 .

Description

Shell: Small (maximum height 5.84 mm), typical Laevilitorina morphology: fusiform with rounded to almost convex whorls, suture impressed, concave spire profile, apex blunt. Macroscopic spiral and axial sculpture absent, but fine growth lines on whole shell. Aperture ovoid, expanded and ≤ 56% of total H ( Fig. 3A–C ). Peristome continuous, columella smooth and oblique, inner lip barely reflected over narrow and shallow umbilicus; outer lip thin, simple, with no evidence of thickening.Teleoconch opaque but last whorl slightly translucent. Colour uniformly reddish brown to dark brown ( Fig. 3A–C ). Operculum corneous. Mature H 4.70–5.84 mm (H/B = 1.00–1.41, SH = 1.60–2.00) (Supporting Information, Table S2).

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

Radula: Rachidian: shows seven cusps, central cusp longest ( Fig. 3D ), sometimes rounded with small denticles at end ( Fig. 3E ). First pair of flanking cusps pointed; outer cusps much smaller, pointed or rounded. Lateral: six or seven cuspids ( Fig. 3F ), main cusp more rounded, accompanied by two or three pointed outer cusps and three continuously smaller inner cusps. Inner marginal: six or seven cusps, of similar size, main cusp rounded, accompanied by one or two pointed outer cusps and four rounded inner cusps. Outer marginal: seven to nine thin and pointed cusps.

Holotype dimensions: Length 5.49 mm, width 4.25 mm.

Depositories: Holotype MNHNCL MOL-205434. Museo Nacional de Historia Natural, Chile.

Type locality: Boquerón, Tierra del Fuego (−53.753758°S, − 70.143961°W), Strait of Magellan, Chile ( Fig. 3G ).

Habitat: Rocky intertidal to subtidal shores on both sides of the Strait of Magellan, including Tierra del Fuego ( Fig. 3G ).

Material studied: Chabunco (− 52.987406°S, − 70.812342°W), n = 20; Santa María Bay, Tierra del Fuego (− 53.392628°S, − 70.373514°W), n = 30; Boquerón, Tierra del Fuego (− 53.753758°S, − 70.143961°W), n = 40.

Etymology: The type locality of this Laevilitorina species is Tierra del Fuego Island in the Strait of Magellan.

Remarks: Laevilitorina fueguina is characterized by its reddishbrown colour ( Fig. 3A–C ) and the presence of denticles on the main teeth of the rachidian, which may vary in number from two to four ( Fig. 3D, E ). The coloration of L. fueguina is similar to that of the Antarctic nominal species L. claviformis and L. umbilicata . Shell morphology of L. fueguina resembles that of L. caliginosa s.s. and L. magellanica , but levels of molecular divergence, species delimitation analyses, radular morphology, shell coloration, and geometric morphometrics differentiate it as a distinct evolutionary unit.

Figures

Figure 3. Laevilitorina fueguina, Boquerón and Chabunco, Tierra del Fuego and Brunswick Peninsula, southern South America.Scale bars: 1 mm unless specified otherwise. A–C, shell morphology and coloration of L. fueguina from Boquerón, Tierra del Fuego (A, B) and from Chabunco, Strait of Magellan (C). D–F, radular morphology (SEM), showing a general view (D), rachidian showing denticles (white arrow; E), and lateral view (F). G, distribution of L.fueguina in the Strait of Magellan.