The depressed river mussel or compressed river mussel, Pseudanodonta complanata, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. The species name comes from the flattened shape of its shell.
This species is found throughout northern Europe, but it is endangered throughout its range.
While the survival of this species is thought to be threatened by pollution and the dredging of the slow-moving channels of water in which it lives, the species is also said to be "easily overlooked" (it can be confused with Anodonta anatina or juvenile Anodonta cygnea) and thus it may be actually be more prevalent than current records show .
Distribution Its native distribution is European. It has been recorded from: Czech Republic - in Bohemia, in Moravia, Horsák M., Juřičková L., Beran L., Čejka T. & Dvořák L. (2010). "Komentovaný seznam měkkýšů zjištěných ve volné přírodě České a Slovenské republiky. [Annotated list of mollusc species recorded outdoors in the Czech and Slovak Republics]". Malacologica Bohemoslovaca, Suppl. 1: 1-37. PDF. endangered (EN). It is endangered in Bohemia and critically endangered in Moravia.Juřičková L., Horsák M. & Beran L., 2001: Check-list of the molluscs (Mollusca) of the Czech Republic. Acta Soc. Zool. Bohem., 65: 25-40. Estonia - present. Finland - not uncommon. Germany critically endangered (vom Aussterben bedroht) Glöer P. & Meier-Brook C. (2003) Süsswassermollusken. DJN, pp. 134, strana 109, Listed as strictly protected species and as specially protected species in annex 1 in Bundesartenschutzverordnung. Netherlands - present Poland - endangered
Slovakia - endangered Měkkýši (Mollusca) České republiky a Slovenska United Kingdom - see Action plan for Pseudanodonta complanata, (British Isles - listed in List of endangered species in the British Isles) Sweden - rare
References
Polish Red Data Book of Animals: Pseudanodonta complanata Action plan for Pseudanodonta complanata Nature Navigator: Detail of Depressed River Mussel