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Perisphinctidae

family

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

Perisphinctidae is a family of Middle and Upper Jurassic discoidal ammonites in the order Ammonitida. They have a shell morphology that is mostly evolute, typically with biplicate, simple, or triplicate ribbing. Large forms have simple apertures and smooth body chambers while small forms have lappets and ribbed body chambers.The ammonites of Perisphinctidae were derived from the ancestral Stephanoceratidae in the Middle Jurassic Bajocian: perisphinctid ammonites ranged from the Bajocan until the Tithonian at the end of the Jurassic. This family forms the root stock of the Perisphinctoidea which gave rise directly or indirectly to the other perisphinctoid families. The Treatise on Invertebrate Paleontology (Part L, 1957) includes the subfamilies Leptosphinctinae, Zigzagiceratinae,…