77. Sphaerium solidum (Normand, 1844)

Findings in Serbia.

Sphaerium solidum: Matoničkin et al. (1975); Popović et al. (2013); Martinović-Vitanović et al. (2013); Tomović et al. (2014); Raković (2015).

Common name. Witham orb mussel.

Morphology. Small bivalve. Rounded triangular shell with prominent umbos. Typical dimensions of the shell are length 9–11 mm, height 7–9.5 mm, and depth 5–7 mm. For more details see Welter-Schultes (2012: 25, figure at the bottom of the page).

Distribution and ecology. Western Palearctic species found in large lowland rivers (rarely lakes) of central and eastern Europe, rarely found in western Europe. It prefers coarse sandy substrate (van Damme et al. 2012). In Serbia it was found in the Danube and Sava Rivers.

Other remarks. This species is on the IUCN list of threatened species as NT (Van Damme et al. 2012). Two nominal species are known as synonyms. On the IUCN Red List it has been assessed as NT (Killeen et al. 2011 c).

Order Myida Stoliczka, 1870