What is the true name for european populations of the slug Arion lusitanicus?

The name Arion lusitanicus can no longer be applied to this taxon. A recent re-description of lusitanicus sensu Mabille, based on topotypes from Setúbal, Serra da Arrábida, Portugal (Castillejo 1997) has shown that Portuguese lusitanicus has a very different spermatophore and internal morphology from the central and west European species to which this name was applied, first by Altena (1956) and then by subsequent authors. Falkner et al. (2002) have proposed that the north-west European species be called vulgaris Moquin-Tandon, 1855 as this is the first name which can be unambiguously applied. British authors including Quick (1960) confused vulgaris with Arion flagellus Collinge. Some of Quick’s drawings of ‘lusitanicus’ (= vulgaris), particularly of the spermatophore, actually relate to flagellus. The reader is directed to Davies’ (1987) paper which first resolved the confusion here and gives a detailed account of the distinguishing features and reproductive biology of both species.

References
ALTENA C. O. VAN REGTEREN 1956 Notes sur les limaces, 3. (Avec la collaboration de Mm. D. Atenet A. R. Schouten) Sur la présence en France de’Arion lusitanicus Mabille Journal de Conchyliologie
95: 89-99.
CASTILLEJO J. 1997. Babosas del Noroeste Ibérico Universidade de Santiago de Compostela, Spain. 192pp.
FALKNER G., RIPKEN T. E. J. & FALKNER M. 2002. Mollusques continentaux de France Liste de Référence annotée et Bibliographie. Patrimoines Naturels, 52, Museum d’Histoire Naturelle, Paris. 350pp.
QUICK H.E. 1960 British slugs (Pulmonata: Testacellidae, Arionidae, Limacidae) Bulletin of the British Museum (Natural History) Zoology 6: 1-226.

Distribution and genetic diversity of slugs Arion lusitanicus and A. rufus in Poland

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The slugs Arion lusitanicus and Arion rufus inhabit ecologically degraded areas and are serious vegetation pests. In recent years, new localities of these species have been found in various parts of Poland. Soroka et al. (2009) study the morphology of 90 specimens from 9 populations of slugs. The morphology of the genital system allowed for the identification of 60 A. lusitanicus specimens from 6 populations and 30 A. rufus individuals from another 3 localities. In order to describe their genetic diversity at the level of the individual, population, and species, they compared sequences of the mitochondrial cytochrome oxidase subunit I (cox1) gene. The morphological analysis revealed that each of the studied populations comprised a single species, which was also confirmed by the molecular assay. 674-bp sequences of the cox1 gene for each species that showed a total of eight haplotypes were obtained. The genetic diversity of A. lusitanicus individuals ranged from 0.5% to 2.1%, whereas that of A. rufus was twice as low: 0.4-1.0%. The difference between the two species within the cox1 gene was at the level of 12%. Three A. lusitanicus and two A. rufus populations were found to be monomorphic. Large inter-population variability was found within each of the studied species, which suggests that the Polish populations of A. lusitanicus may have originated from repeated, separated introductions arriving from various parts of Europe.

References

SOROKA M., KOZŁOWSKI J., WIKTOR A., KAŁUSKI T. 2009. Distribution and genetic diversity of the terrestrial slugs Arion lusitanicus Mabille, 1868 and Arion rufus (Linnaeus, 1758) in Poland based on mitochondrial DNA. Folia biol. (Kraków) 57: 71-81.