Ferrissia californica ( Rowell, 1863 )

Marković, Vanja, Gojšina, Vukašin, Novaković, Boris, Božanić, Milenka, Stojanović, Katarina, Karan-Žnidaršič, Tamara & Živić, Ivana, 2021, The freshwater molluscs of Serbia: Annotated checklist with remarks on distribution and protection status, Zootaxa 5003 (1), pp. 1-64 : 28

51. Ferrissia californica ( Rowell, 1863)

Findings in Serbia.

Ferrissia wautieri: Velkovrh (1974) .

Ferrissia fragilis: Raković (2015) ; Gojšina (2021, pers. comm.); Stojanović (2021 pers. comm.).

Common name: Fragile ancylid.

Morphology. Small-sized snail, up to 6 mm long. Flattened, translucent and thin shell with apex bent to the right side. For more details see Welter-Schultes (2012: 49, figures in the middle of the page).

Distribution and ecology. Invasive species (Nearctic orign), wide ecological valence. Often found on submerged water plants. Prefers shallow stagnant or slowly flowing waters ( Glöer 2019). In Serbia, reported from the Danube, a flooded gravel pit near the Nera River, and few smaller ponds (Tvrdenjava near Belgrade, Vrnjačka banja Spa).

Other remarks. The species can be confused with Acroloxus lacustris sometimes. It tolerates droughts by forming a septum and closing the shell. This species is often found in clusters, with two or more smaller individuals sticking on the back of the larger one ( Glöer 2019). On the IUCN Red List of threatened species, it has been assessed as LC ( Cordeiro & Perez 2011).