Site-specific attachment of <i>Anodonta anatina</i> (Bivalvia: Unionidae) glochidia on two new fish hosts translocated in Lake Trasimeno (Italy)

To complete their life cycle, freshwater mussels of the order Unionida depend on fishes as hosts for obligatory parasitic larval phase, glochidium. Here we report first documentation gobioid glochidia unionid in wild Italy and southern Europe (outside Danube drainage area). We also examined pattern attached glochidia. A recent review reported 326 fish species suitable unionids, but only eight (2.5%) these were Gobioidei. Host identification benefits or threats interaction with is important conservation mussels. But co-existence non-native poorly understood, including compatibility two groups. Knipowitschia panizzae Pomatoschistus canestrinii , translocated sand gobies, sampled 2022 at east shore Lake Trasimeno (Italy). Two anodontine present this locality, native Anodonta anatina Sinanodonta woodiana . Genetic data revealed that both gobies hosted A. not S. possibly because seasonal bias. About 50% specimens infested. The paired fins most prominent targets. individuals carried few (max. 5). Nevertheless, showed a divergent attachment.