Clam shrimp

The mussel Schaler ( Conchostraca ) include in addition to the Feenkrebsen ( Anostraca ) and the back saddle learning ( Notostraca ) to the Branchiopoda or "Primeval crabs " and are thus to be counted among the living fossils. They are available since the Silurian in virtually unchanged form.

The mussel bivalves are classified within the Branchiopoda in the order of the claws tails, but the position of this group ( taxon ) within the scheme of Blattfußkrebse or its validity as a separate taxon is still under scientific debate. More recently, the majority tends to the view that the mussel Schaler not form a natural unit.

They owe their name to their two-part or two-lobed shell that protects them from injury, and externally reminiscent of a seashell. They are between 0.5 and 2 cm long, and filter their food, which is usually made of suspended particles or algae from the water. Their habitat are often short term existing ( astatic ) waters. Their development from egg to adult animals occurs within a few days, the hard-shelled eggs are able to survive even a longer drying out of the water, heat or frost.

Mussel bivalves are rare and not to be confused with the commonly occurring ostracods.