Laevilitorina venusta Pfeffer, 1886

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 : 8-10

Laevilitorina venusta Pfeffer, 1886

( Fig. 5 )

Hydrobia caliginosa – Smith, 1879: 173, pl. 9, fig. 8; Watson 1886: 613.

Laevilitorina venusta – von Martens and Pfeffer 1886: 85, pl. 1, fig. 9a, b; Castellanos 1989: 18; Zelaya 2005: 118; Rosenfeld et al. 2022: 66, fig. 1c.

Litorina (Laevilitorina) coriacea – Melvill and Standen 1907: 130, pl. 1, fig. 2.

Laevilitorina coriacea – Engl, 2012: 103.

Laevilitorina caliginosa – E. Lamy, 1905: 478; E. Lamy, 1906: 112; E. Lamy, 1911: 8.

Laevilitorina caliginosa var. fulleri – Gaillard, 1971.

Laevilitorina caliginosa – Thiele, 1912: 235; Powell, 1957: 128; Arnaud and Bandel 1976: 215, pl. 1, fig. 1; Cantera and Arnaud 1985: 40; Arnaud et al. 1986: 13; Jazdzewski et al. 2001: 93; Waller et al. 2006: 662; Engl 2012: 102; Amsler et al. 2015: 1175; Aghmich et al. 2016: 193; Martín et al. 2016: 212; Schrödl et al. 2016: 40; Rosenfeld et al. 2017: 4; Valdivia et al. 2020: 5; Amsler et al. 2022: 248.

Laevilitorina caliginosa L4 – González-Wevar et al. 2022: 1527.

Description

Shell: Small (maximum height 8 mm), typical Laevilitorina morphology: fusiform, with rounded to almost convex whorls, suture impressed, concave spire profile, apex blunt ( Fig. 5A–G ). Aperture varies from rounded to ovoid, between 46% and 55% of total H (Supporting Information, Table S4). Macroscopic spiral and axial sculpture absent, but multiple fine growth lines cover shell. Columella smooth, inner lip barely reflected over narrow and shallow umbilicus, outer lip thin, simple and with no evidence of thickening. Teleoconch opaque, but the last whorl slightly translucent. Significant colour variability characterizes populations of L. venusta , ranging across dark red, grey, brown, dark brown, and black ( Fig. 5A–G ). Some individuals uniformly coloured, others with small white spots, irregular in size and position. Operculum corneous. Mature H 3.2–8 mm (H/B = 1.21– 1.40, SH = 1.66–1.98) (Supporting Information, Table S4).

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

Radula: Rachidian: five to seven cusps, the central cusp is long, rectangular and very rounded ( Fig. 5H–J ), sometimes with a few small denticles at the end ( Fig. 5I ); first pair of flanking cusps pointed; outer cusps may be present as low, pointed cusps. Lateral: six or seven cusps, main cusp largest, broadest and rounded, accompanied by two smaller, pointed outer cusps and three or four continuously smaller pointed inner cusps. Inner marginal: five or six cusps, main cusp pointed and rectangular, accompanied by one or two smaller, very pointed outer cusps and four pointed inner cusps of similar size. Outer marginal: eight or nine thin and pointed cusps.

Habitat: Rocky intertidal to subtidal shores of the Antarctic Peninsula, the South Shetland Islands, and Signy Island, in addition to sub-Antarctic Islands including South Georgia, Marion, Crozet, Kerguelen, and Macquarie ( Fig. 5K ).

Material studied: Penguin Island, South Shetland Islands (− 62.103992°S, − 57.939050°W); Arctowski Base, Admiralty Base, King George Island , South Shetland Islands (− 62.158336°S, − 58.467525°W); Fildes Bay , King George Island , South Shetland Islands (− 62.207967°S, − 58.956914°W), n = 100; Rizopatrón Base, Coppermine Cove, Robert Island , South Shetland Islands (− 62.390567°S, − 59.659075°W), n = 50; Hannah Point, Livingstone Island , South Shetland Islands (− 62.651181°S, − 60.594664°W), n = 50; Prat Base, Greenwich Island , South Shetland Islands (− 62.479594°S, − 59.669044°W), n = 100; Deception Island , South Shetland Islands (− 62.930139°S, − 60.606333°W), n = 40; Yelcho Station , Doumer Island , South Bay , Anvers Island , Antarctic Peninsula (− 64.893792°S, − 63.562572°W), n = 50; Carvajal Base, Adelaide Island , Antarctic Peninsula (− 67.761989°S, − 68.915303°W), n = 50; Avian Island , Marguerite Bay , Antarctic Peninsula (− 67.772225°S, − 68.897947°W), n = 100; O’Higgins Base, Covadonga Bay, Antarctic Peninsula (− 63.320436°S, − 57.898353°W), n = 80; Signy Research Station, Signy Island, South Orkneys Islands (−60.722839°S, − 45.587817°W), n = 30; Cumberland Bay, South Georgia (− 54.283364°S, − 36.486956°W), n = 100; Ships Cove, Marion Island (− 46.854506°S, − 37.845100°E), n = 10; Baie American, Crozet Islands (− 46.426181°S, 51.861806°E), n = 50; Portaux-Français, Kerguelen Islands (− 49.352733°S, 70.218303°E), n = 100; Port Christmas, Kerguelen Islands (− 48.677607°S, 69.023604°E), n = 30; Îles du Prince-de-Monaco, Kerguelen Islands (− 49.606278°S, 69.235900°E), n = 30; Garden Cove, Macquarie Island (− 54.501287°S, 158.936221°E), n = 20.

Remarks: Several specimens in the study by González-Wevar et al. (2022) collected from South Georgia that fell in the L4 clade of L. caliginosa s.l. were characterized by a short spire and 4.5 convex whorls, with the aperture height occupying little more than half of the total shell height; the columellar callus was sharp, white, and expanded towards the umbilicus (morphological characteristic highlighted by von Martens and Pfeffer 1886), all features consistent with the original description of L. venusta (Pfeffer, 1886) . Moreover, the type locality of L. venusta is South Georgia. Thus, in this revision we conclude that the L4 ‘ caliginosa ’ lineage of González-Wevar et al. (2022) is, in fact, L. venusta . The genetic data show that this species also includes populations from maritime Antarctica (South Shetlands Islands and the Antarctic Peninsula), in addition to geographically distant sub-Antarctic Islands ( South Georgia, Marion, Crozet, Kerguelen, and Macquarie). Laevilitorina venusta and L. caliginosa s.s. are the Laevilitorina species with broadest morphological variability and geographical distributions. We also include L. coriacea ( Melvill and Standen 1907) from the South Orkney Islands as a synonym; previously (e.g. Engl 2012), this taxon was considered synonymous with L caliginosa .

Figures

Figure 5. Laevilitorina venusta, Southern Ocean.Scale bars: 1 mm unless specified otherwise.A–G, variation in shell morphology and coloration of the species across its distribution in different provinces of the Southern Ocean.The specimens of L. venusta are from:Greenwich Island, South Shetland Islands, Antarctic Peninsula (A); Covandonga Bay, the Antarctic Peninsula (B); South Georgia (C); Marion Island (D); Crozet Island (E); Kerguelen Island (F); and Macquarie Island (G). H–J, radular morphology (SEM), showing a general view (H), rachidian (I), and rachidian from an individual from Antarctica showing small denticles (J). K, distributional pattern of L. venusta across the Southern Ocean.