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Arcida

order

“Arcoida”

Sensitive Classification

Fossils are sensitive in nature and should not be collected unless it is done legally and responsibly. Vertebrate fossils are illegal to collect on public lands.

On the Web

On Wikipedia

The Arcida is an extant order of bivalve molluscs. This order dates back to the lower Ordovician period. They are distinguished from related groups, such as the mussels, by having a straight hinge to the shells, and the adductor muscles being of equal size. The duplivincular ligament, taxodont dentition, and a shell microstructure consisting of the outer crossed lamellar and inner complex crossed lamellar layers are defining characters of this order.Seven families are currently recognised within the order, including the well-known ark clams or ark shells in the family Arcidae.

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You have noted 0 Arcida

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Range Maps show field notes recorded by Natural Atlas contributors and other datasets via GBIF.org

Formations Found In

Pierre Shale (SDKp;0)

9,518 Observations

Fox Hills Sandstone

5,558 Observations

Fox Hills Sandstone (SDKfh;0)

5,449 Observations

Landslide Deposits (SDQl;0)

1,059 Observations

Miocene marine rocks (CAMI;0)

467 Observations

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Arcida

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