Atrypa
Atrypa is a genus of brachiopod with shells round to short egg-shaped, covered with many fine radial ridges, that split further out and growthlines perpendicular to the costae and 2-3 times wider spaced. The pedunculate valve is a little convex, but tends to level out or even become slightly concave toward the anterior margin. The brachial valve is highly convex. There is no interarea in either valve. Atrypa was a cosmopolitan and occurred from the late Lower Silurian to the early Upper Devonian. Other sources expand the range from the Late Ordovician to Carboniferous, approximately from 449 to 336 Ma. A proposed new species, A. harrisi, was found in the trilobite-rich Floresta Formation in Boyacá, Colombia.Reassigned species
As Atrypa was erected early on, many species have been reassigned since.Organic content of ''Atrypa'' fossils
In some fossil material, organic compounds may be preserved. Only the more stable amino acids tend to be preserved in very old fossils. In specimens of Atrypa reticularis from the Wenlock Shales, alanine, glycine, glutamic acid, leucine, isoleucine, proline, valine, and aspartic acid have been found.Gallery
