Land flatworms (Tricladida: Geoplanidae) in France and French overseas territories: ten years of research

ABSTRACT Since 2013, we have undertaken a detailed study of terrestrial flatworms (Geoplanidae) introduced into mainland France (including Corsica). Around ten species have been listed, mapped, and often characterized molecularly. These species include, in alphabetical order, Bipalium kewense, Caenoplana coerulea, Caenoplana decolorata, Caenoplana variegata, Diversibipalium multilineatum, Marionfyfea adventor, Obama nungara, Parakontikia ventrolineata, Platydemus manokwari, and Vermiviatum covidum. Outside of mainland France, we also studied species from the French islands of the Caribbean (Guadeloupe, Martinique), Réunion and Mayotte in the Indian Ocean, as well as New Caledonia, French Polynesia, and Wallis and Futuna in the Pacific. Two new species have been described. The major invasive species in mainland France are Obama nungara, present in two thirds of the country, Caenoplana variegata, and Parakontikia ventrolineata (especially in Brittany). Bipalium kewense and Diversibipalium multilineatum are mainly present in the southwest region of the French Atlantic coast. The origins of invasive species in France are varied and include Argentina (Obama nungara), Australia (Caenoplana variegata and Parakontikia ventrolineata), and Southeast Asia (Bipaliinae). We have characterized and published the complete mitogenomes of 12 species, with unexpected results, such as the very long cox2 gene in Rhynchodeminae. The phylogenies built on the genes of the mitogenomes generally confirm the previous classifications of the subfamilies of Geoplanidae, and individualize the three subfamilies Rhynchodeminae, Geoplaninae, and Bipaliinae. We emphasize the importance of citizen science for obtaining data, and the importance of good communication with the public to obtain significant engagement towards citizen science.