Belongs within: Unioninae. Anodonta is a genus of freshwater mussels in which the shell is oblong, thin, and rather compressed behind, and the hinge margin lacks teeth (Gray 1840). The shells of ducks and swans Published 18 April 2021 The freshwater environment has been a challenging one for bivalves. Though there is a reasonable diversity… Continue reading Anodonta


Belongs within: Palaeoheterodonta.Contains: Mutela (Mutela), Aspatharia (Spathopsis). The Mutelidae are a family of freshwater clams found from the Cretaceous to the present day, characterised by a greatly reduced dentition in the hinge. Characters (from Cox et al. 1969): Shell mostly unsculptured; beaks smooth or faintly corrugated, without well-defined remains of embryonic shell; hinge with cardinals… Continue reading Mutelidae


Belongs within: Ambleminae. Epioblasma is a genus of North American freshwater mussels, most of which are now severely endangered, several recently becoming extinct. Characters (from Smith 2001): Shell usually less than 60 mm in length, posterior half sulcate or with one or two radiating ridges, sometimes with fine wrinkles or costae; sexual dimorphism strongly pronounced;… Continue reading Epioblasma


Belongs within: Bivalvia.Contains: Actinodontoida, Unionidae, Margaritiferidae, Mutelidae, Trigoniidae, Myophoriidae. The Palaeoheterodonta is a clade of bivalves represented in the modern fauna by two quite divergent subclades, the angular-shelled Neotrigonia (sole surviving lineage of the Trigonioida) and the freshwater clams of the Unionoida. Though the integrity of the Palaeoheterodonta has been questioned in the past, monophyly… Continue reading Palaeoheterodonta


Belongs within: Ambleminae. Pig’s toes and water nymphs Published 29 September 2008 In contrast to the great diversity of freshwater gastropods, surprisingly few groups of bivalves have really made a go of things in the freshwater environment. The superfamily Unionoidea is therefore very distinctive in not only including the largest number of freshwater bivalves, but… Continue reading Pleurobemini