Clypeaster rogersi

Phylum Echinodermata
Class Echinoidea
Order Clypeasteroida
(Scale bar is 1 cm)

One of two common species of Clypeaster in lower Oligocene rocks, this one is easily recognized by its nearly flat bottom (lower photo above). C. cotteaui has a strongly concave oral surface in contrast. The two species usually occur in different beds even when they are found at the same locality.

In this respect they are like the two modern species of the genus that live in the Caribbean region: C. subdepressus and C. rosaceus which live in different ways. The former is relatively flattened (like C. rogersi) and lives buried shallowly in sandy bottoms. The latter is more inflated (like C. cotteaui) and lives at the surface of the sediment rather than within it.

The morphology of the test of C. rogersi suggests that it burrowed to shallow depths in coarse sediment, and it is invariably found with that type of sediment.

The species is known only from lower Oligocene (Vicksburgian or Rupelian) rocks, specifically the undifferentiated residuum in Georgia.

AGE: EARLY OLIGOCENE

FORMATION: RESIDUUM

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