Ostracods (Ostracoda)

Ostracods are microscopic crustaceans, typically 0.2mm to 2mm long, with a bivalved calcareous shell. They first emerged around 500 million years ago and today inhabit every aquatic environment on earth.

Ostracods are found in a wide range of environments:

  • Ostracod specimen.
    the deep oceans
  • estuaries
  • lagoons
  • freshwater
  • salt lakes
  • hot springs
  • damp terrestrial environments

Their lifestyle ranges from free swimming to interstitial, where they rest among sediment. Ostracods can be:

  • benthic carnivores or herbivores, crawling and scavenging (most are)
  • filter feeders
  • parasitic

Occurrence:

Ordovician to present day. This group has living relatives.

Ostracods as fossils

Ostracods are minute but readily fossilised, and can occur in enormous numbers in some sediments. 

Their fossils are widely distributed and are often found alongside foraminifera.

  • Ostracod specimen.
    Ostracod collections

    The Museum has enormous collections of ostracods, both fossil and non-fossil specimens. Learn more about the collections and search the fossil and recent ostracod database.

Find out more
Ostracod specimen.
Ostracod collections

The Museum has enormous collections of ostracods, both fossil and non-fossil specimens. Learn about the most important of these.