""'Atrypa " "'is a genus of brachiopod with shells round to short egg-shaped, covered with many fine radial ridges ( or costae ), that split further out and growthlines perpendicular to the costae and 2-3 times wider spaced.
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There is no interarea ( that is a flat area bordering the hinge line approximately perpendicular with the rest of the valve ) in either valve . " Atrypa " was a cosmopolitan and occurred from the late Lower Silurian ( Telychian ) to the early Upper Devonian ( Frasnian ).
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