Abstract
The marine gastropod genus Laevilitorina is exclusive to the Southern Hemisphere, with 21 species from southern South America, Antarctica, Australia, New Zealand, and sub-Antarctic Islands. We present a comprehensive revision of Laevilitorina, using molecular and morphological analyses, to address formally the interspecific divergences within the nominal taxon Laevilitorina caliginosa s.l. We confirm the validity of L. caliginosa and Laevilitorina venusta, and we demonstrate that specimens from the Strait of Magellan and Hornos Island constitute four new species here described: Laevilitorina magellanica sp. nov., Laevilitorina pepita sp. nov., Laevilitorina fueguina sp. nov., and Laevilitorina hicana sp. nov. All six species are clearly distinguishable genetically, morphologically, and through radular tooth shape and configurations. Laevilitorina venusta is broadly distributed across the Antarctic Peninsula, South Georgia, and sub-Antarctic Islands (Marion, Crozet, Kerguelen, and Macquarie), whereas L. caliginosa s.s. appears geographically restricted to Cape Horn, the Falkland/Malvinas Islands, and South Georgia. The identification of populations from Macquarie Island as L. caliginosa is dubious; we suggest that these records are likely to pertain to L. venusta. This detailed revision of Laevilitorina, whereby hidden diversity was detected, significantly enriches our knowledge of the evolutionary history of this group.