Cryptic diversity in smooth-shelled mussels on Southern Ocean islands: connectivity, hybridisation and a marine invasion

Research on smooth-shelled mussels (Mytilus spp.) around the New Zealand Sub-Antarctic Islands reveals that these populations exhibit mixed genome ancestry, indicating native origins rather than human introduction. Using single nucleotide polymorphism (SNP) analysis, scientists found that mussels from the Falkland and Kerguelen Islands are closely related to M. platensis from South America, suggesting dispersal via ocean currents. Meanwhile, mussels from Tasmania, mainland New Zealand, and offshore islands form a distinct Southern Hemisphere group with affinities to Northern Hemisphere M. galloprovincialis. The study also detected hybridisation between taxa, with invasive M. galloprovincialis identified only in Tasmania. These findings highlight the importance of preserving native evolutionary lineages, particularly on remote islands where small populations may be vulnerable to invasion and genetic dilution.

Zbawicka, M., Gardner, J. P. A., & Wenne, R. (2019). Cryptic diversity in smooth-shelled mussels on Southern Ocean islands: connectivity, hybridisation and a marine invasion. Frontiers in Zoology, 16(1). https://doi.org/10.1186/s12983-019-0332-y