Snails likely reached Antarctica riding on floating macroalgae

A study led by scientists at the University of Chile suggests that small Antarctic and sub-Antarctic snails may have colonized new territories by riding on floating macroalgae, such as cochayuyo, across the Southern Ocean millions of years ago. The research, published in Proceedings of the Royal Society B, focused on two closely related snail genera, Laevilitorina and Laevilacunaria, which share similar life cycles and habitats yet show strikingly different distributions and species richness Source: hoydo.

The journey

The snails lack free-swimming larvae, so the team investigated how they crossed vast oceanic distances. They propose that macroalgae, when detached from rocks, can drift with currents, carrying adult snails, juveniles, or egg masses. "All organisms attached to it go with it," explained researcher Sebastián Rosenfeld Source: clarin. The analysis suggests one dispersal event occurred about 7.9 million years ago, possibly from the sub-Antarctic Kerguelen Islands to West Antarctica, with later spread to South Georgia Source: emolcl. These events were likely rare, possibly triggered by storms Source: infobae.

Unexpected finding

The study also revealed an unexpected taxonomic result: although Laevilitorina and Laevilacunaria are currently considered two closely related genera, the genetic and morphological analyses identified four distinct evolutionary clades that may represent separate genera. "We are possibly in the presence of four genera," said Rosenfeld Source: hoydo. This finding opens new avenues for understanding the group's diversity Source: emolcl.

Implications

Co-author Elie Poulin, director of the Millennium Institute BASE, noted that understanding how these species originated and diversified can help anticipate their responses to accelerated environmental changes Source: infobae. The study underscores how much remains unknown about Southern Ocean biodiversity Source: clarin.