Laevilitorina umbilicata Pfeffer, 1886

Zettler, Michael L. & Bick, Andreas, 2025, Molluscs from a shallow bay of King George Island (Antarctica, South Shetland Islands): An annotated checklist with new distributional records, Zootaxa 5631 (3), pp. 401-450 : 431

37. Laevilitorina umbilicata Pfeffer, 1886 [ Figs 14H–K ]

Laevilitorina umbilicata Pfeffer, 1886: 88 , pl. 1, fig. 12 [in Martens & Pfeffer 1986]

Material examined. • 557 spms, Stn. 2; • 7 spms, Stn. 9; • 1 spm, Stn. 12.

Type locality. South Georgia.

Bathymetric distribution. 0–40 m.

Substrate. Hard bottom, grazing on macroalgae or stones.

Geographical distribution. ANTARCTICA: Antarctic Peninsula. SUBANTARCTICA: -. SCOTIA ARC: South Georgia, South Orkney Islands, South Shetland Islands. SOUTH AMERICA: -.

Remarks. Similar to Engl (2012), the material we found consisted of both smooth and spiral-banded specimens. Laevilitorina umbilicata was by far the most common species in our study area and was found almost exclusively in the intertidal zone. There was only one single finding from a depth of 15 m. Laevilitorina umbilicata can be confused with L. antarctica (E. A. Smith, 1902) . However, it is slender and the whorls are not as distinct. Laevilitorina antarctica is more restricted to the Antarctic proper and L. umbilicata to the Antarctic Peninsula and the islands of the Scotia Arc, however, both overlap in their distribution area in South Shetland Islands and Antarctic Peninsula ( Rosenfeld et al. 2022). While L. umbilicata is found in masses under stones in the immediate intertidal zone of King George Island ( Aldea et al. 2016; this study), L. antarctica obviously prefers to colonise macroalgae in greater depths (9 to 20 m) ( Martín et al. 2016; Amsler et al. 2022). There are a number of literature records of L. antarctica from very shallow South Shetland Islands, but it can be assumed that at least some of them are misidentifications. On the other hand, phylogenetic reconstructions of the Antarctic species L. antarctica , L. claviformis Preston, 1916 , and L. umbilicata failed to discriminate them as different evolutionary units ( Rosenfeld et al. 2024). If it is confirmed that they cannot be separated genetically, both L. antarctica and L. claviformis would have to be placed in the synonymy of L. umbilicata . However, a review is not the subject of this investigation. The species is already known from Maxwell and Admiralty Bays.

References. Arnaud et al. (1986), Engl (2012), Aghmich et al. (2016), Aldea et al. (2016), Martín et al. (2016), Amsler et al. (2022), Rosenfeld et al. (2022, 2024).

Figures

FIGURE 14. A–C: Laevilacunaria antarctica (E. von Martens, 1885); D–G: Laevilitorina venusta Pfeffer, 1886; H–K: Laevilitorina umbilicata Pfeffer, 1886; L–M: Pellilitorina pellita (E. von Martens, 1885). Unless otherwise indicated, the scale is always 1 mm.