Multiple introductions and successful establishment of the invasive land snail Rumina decollata

Abstract Biological invasions comprise a major component of global change and biodiversity loss. Human-mediated dispersal introduced Rumina decollata, a Mediterranean land snail, beyond its native range, and the species is now widely distributed across much of Argentina. Here, we analysed mitochondrial COI sequences from specimens collected across a broad latitudinal and environmental gradient in Argentina to investigate their relationships with lineages reported from the native and introduced ranges. All analysed specimens clustered within the mitochondrial lineage previously identified as invasive worldwide. One haplotype identical to sequences reported from Spain and Portugal was detected in 21 of the 23 sampled localities, whereas two additional haplotypes matched lineages previously recorded from Portugal and southern France. These results support multiple introduction events into Argentina, followed by secondary spread. Body and sole colouration varied among individuals and showed no consistent association with mitochondrial lineages. Our findings provide the first broad-scale assessment of mitochondrial lineages of R. decollata in Argentina and contribute to understanding the introduction history of this invasive land snail. Competing Interest Statement The authors have declared no competing interest. Footnotes This version of the manuscript has been revised to update the following: The title and author list were updated, with Guerrero Spagnuoli, J. and Dop, N.S. now indicated as co-first authors. The Discussion and Methods sections were revised to more accurately reflect the limitations of the sampling design (one individual analysed per locality), with claims about genetic diversity and self-fertilisation reframed accordingly. The Methods section was expanded with additional detail on sample selection, specimen collection, and analytical justifications. The Introduction was expanded with a clearer definition of molecular operational taxonomic units (MOTUs) and additional recent literature on invasive land snails in South America. A figure on colour variation, previously in the supplementary material, was moved into the main text.