The freshwater molluscs of Serbia: Annotated checklist with remarks on distribution and protection status Author Marković, Vanja Author Gojšina, Vukašin Author Novaković, Boris Author Božanić, Milenka Author Stojanović, Katarina Author Karan-Žnidaršič, Tamara Author Živić, Ivana text Zootaxa 2021 2021-07-16 5003 1 1 64 journal article 218052 10.11646/zootaxa.5003.1.1 aceedc3f-3f24-490c-8046-7528c30aac10 1175-5326 5120059 8C98CC0B-18AF-418A-A794-AA3CA9CB7409 73. Pisidium obtusale ( Lamarck, 1818 ) Findings in Serbia . Pisidium obtusale : Martinović-Vitanovic et al. (2013) . Common name . Porous shelled pea mussel. Morphology . Minute bivalve. Oval shell is small, very tumid (almost spherical) with a very rounded ventral margin. It reaches about 3.5 mm in length, 3 mm in height, and 3 mm in depth. For more details see Welter-Schultes (2012: 21 , figure at the bottom of the page). Distribution and ecology . Holarctic species being found usually in smaller standing waters such as swamps, ponds, and marsh drains with dense aquatic vegetation. It prefers muddy, silty substrates, usually with a high organic content (Van Damme 2011 b ). In Serbia , it was recorded in the Danube. Other remarks . It has been assessed as LC on the global and European IUCN level ( Van Damme 2011 b ; Killeen & Seddon 2011 b ).