Suborder Atripidina Order Spiriferida | Family Atrypidae Rank Genus | |
 | ||
Similar Leptaena, Spirifer, Athyris, Favosites, Cyrtospirifer | ||
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. The pedunculate valve is a little convex, but tends to level out or even become slightly concave toward the anterior margin (that is: opposite hinge and pedicle). The brachial valve is highly convex. 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).
Contents
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 (Lower Silurian), alanine, glycine, glutamic acid, leucine, isoleucine, proline, valine, and aspartic acid have been found.
