Theodoxus fluviatilis ( Linnaeus, 1758 )

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 : 9

2. Theodoxus fluviatilis ( Linnaeus, 1758)

Findings in Serbia.

Theodoxus fluviatilis: Matoničkin et al. (1975) ; Karaman (2001, 2012); Jakovčev-Todorović et al. (2005); Paunović et al. (2007a, 2008, 2012 a); Marković et al. (2012, 2013, 2014); Martinović-Vitanović et al. (2013); Tomović et al. (2014).

Common name. River nerite.

Morphology. Medium-sized species. Oval shaped shell has dimensions up to 13 mm. Colouration pattern is extremely variable, ranging from almost black to various bright variants, often with dark zigzag lines, and triangular irregular light flecks. Operculum is reddish, pseudo-apophysis is absent, while apophysis has a wide platelet part. For more details see Glöer (2019: 41, figs 26, 27).

Distribution and ecology. The most widespread among Theodoxus species , this snail is fairly common throughout Europe, and recorded in Asia (Near East) and northern Africa ( Bunje 2005; Glöer 2019). It prefers hard substrate of larger rivers in the region ( Marković et al. 2014). The most abundant populations in Serbia are found in the large rivers such as the Danube, Sava, and Tisza Rivers.

Other remarks. Although being considered of Ponto-Caspian origin ( Bunje 2005) nowadays it is regarded as an introduced, or even an invasive taxon, in the Danube basin by some authors ( Kebapçý & Van Damme 2012). It has LC status on the IUCN Red List ( Seddon & Killeen 2010).