Ostracoda

-Segmented animals with carapace consisting of chitin or calcium carbonate.

-Range in size from 0.5-10mm in size.

-Anterior portion of carapace consists of two valves, inside which the rest of the anmal resides.

-Classification according to the bivalved section which is moulted at regular intervals to allow growth as with other arthopods.
-Fairly poor global fossil record with fossils only found in sporadic, localised beds.

-Permian beds have upto 35 genera, with 87 species of Ostracoda.

-Beds of Triassic age contain 88 genera which are different from those in the Permian, with no evidence of the Permian genera.

-Suggests that there was mass extinction of Ostracoda, with only a few genera surviving through to Triassic. These rapidly diversified to form the Triassic generas.

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