75. Sphaerium corneum (Linnaeus, 1758)

Findings in Serbia.

Sphaerium corneum: Arambašić (1994); Simic & Simic (2004); Raković (2015); Martinović-Vitanović et al. (2007, 2013); Tomović et al. (2010 b, 2014); Paunović et al. (2007 b); Popović et al. (2013).

Common name. Horny orb mussel.

Morphology. Small bivalve. Rounded oval shell is almost equilateral, tumid, and sometimes nearly spherical. Dimensions are length 10–12 mm, height 8–10 mm, and depth 6–7 mm. For more details see Welter-Schultes (2012: 24, figure on the top of the page).

Distribution and ecology. Palearctic species inhabiting fine substrate in a wide range of flowing and standing waters. In Serbia, it was found in large lowland rivers (Danube and Velika Morava Rivers).

Other remarks. This species features a pronounced variation in shell outline, shape and timidity, thus having many morphotypes/names to those distinctive forms. A total of 24 nominal species are used as synonyms (Graf & Cummings 2021). On the IUCN Red List it has been assessed as LC (Killeen & Seddon 2011 c).