Duck mussel[Anodonta anatina (= synonymname A. piscinalis)]
Relationsship and features of typical shells (taxonomy)
AppearanceShell oval and swollen, shaped like an egg. Reaches normally a total length of 8 - 10 cm (in exceptional cases up to 14 cm). The colour is often yellow - olive with lively spots of green. Shell curves dorsally, ascending behind the umbones, so that the upper and lower margins are divergent, not parallel. The upper margin is abruptly passed over to the dorsal (hind) end, which gives it a blunt shape. The shell is increasingly thicker towards the lower part and this is best appearing closer to the anterior (fore) end. Hold the valve towards the centre, between the thumb and the forefinger. Move the fingers in direction to the anterior (fore) end and you will sense the thickening. The umbonal rugae consist of 8 -10 wavy ridges, which are crosswise to the growth lines. The inhalent siphon is wide with short papillae. The colour of the soft tissues is often grey - yellowish grey. There are no hinge-teeth.
BiologyAbundant in all types of inland waters in Sweden, with the exception of the most nutrient poor. It is an opportunistic species with few demands concerning bottom substrate. It can be found even on soft bottom.
DistributionThe most common large freshwater mussel in Sweden. Abundant throughout the Country from Scania in the very south to Lappland in the northern part of Sweden, but is still less abundant in the inner part of Lappland.
Photo: Håkan Holmberg
Scientific basis: Ted von Proschwitz