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Mussel Shrimp: Ostracoda

Behavior And Reproduction

Mussel shrimp have different ways of getting around. Species living on the bottom open their carapace, extend the antennae and limbs, and walk with a rocking motion. Open water species keep their carapaces closed, with just their antennae and limbs poking out. They swim by rowing their appendages through the water.

Both males and females are required for reproduction. Eggs are released into the water or brooded inside the carapace until they hatch. The young hatch as nauplius (NAH-plee-us) larvae (LAR-vee) with folded carapaces covering their bodies. Nauplius larvae have antennae and mouthparts for appendages and use them for walking or swimming. They molt, or shed their external skeletons (exoskeletons), five to eight times before reaching adulthood, adding more appendages with each molt. Mussel shrimp usually live for one year or less.


Mussel shrimp are about 500 million years old. Scientists have described about 65,000 species of fossil ostracods. Distinctive impressions of carapaces left behind by ancient ostracods and other organisms were preserved in layers of sea mud. After millions of years of tremendous pressure, the mud turned to stone. The presence or absence of fossil ostracods in rock samples provides scientists with clues about conditions of ancient habitats and the age of surrounding fossils.

Additional topics

Animal Life ResourceMollusks, Crustaceans, and Related SpeciesMussel Shrimp: Ostracoda - Physical Characteristics, Behavior And Reproduction, No Common Name (vargula Hilgendorfii): Species Account - GEOGRAPHIC RANGE, HABITAT, DIET, MUSSEL SHRIMP AND PEOPLE, CONSERVATION STATUS