The invasive tropical planaria Bipalium kewense invades urban subterranean habitats in the city of Catania (Sicily, Italy)

Numerous records of exotic and invasive predatory flatworms (Geoplanidae) introduced through the commercial trade in potted plants have recently been reported across Europe. Our research in subterranean lava caves revealed the presence of the tropical planaria Bipalium kewense in the urban municipality of Catania, a species native to Asia and one of the most widely distributed non-native planaria worldwide. The specimens were characterized morphologically and via DNA barcoding to confirm species identification and shed light on the possible origin of the Sicilian non-native population. Given its generalist predatory behavior, the presence in subterranean habitats of this flatworm raises concerns in respect to its potential negative effect on the resident fauna, which is notable for its subterranean faunistic peculiarities. This suggests the need for more careful searching and monitoring of subterranean environments in Sicily.