Ostracods

Ostracods are microscopic crustaceans which live in fresh, brackish, saline and hypersaline waters. The majority are 1.5 - 2 mm in length, but some attain up to 80 mm. The calcitic carapaces are are readily fossilized and are widely distributed in sediments of Cambrain to Recent age. They are very useful for intraregional stratigraphy, and in palaeoecological and plaeogeographical studies. Their stratigraphic value was early recognised in oil exploration and at one time were second only to foraminifer in applied micropaleontology.