Perisphinctoidea, formerly Perisphinctaceae, is a superfamily of Middle

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

(Bajocian) to

Lower Cretaceous Lower may refer to: * ''Lower'' (album), 2025 album by Benjamin Booker * Lower (surname) * Lower Township, New Jersey *Lower Receiver (firearms) * Lower Wick Gloucestershire, England See also * Nizhny {{Disambiguation ...

(Barremian)

ammonites Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family N ...

, commonly with evolute shells with strong ribbing that typically divides about mid flank before crossing the venter.

Classification

Some 16 families have been recognized in the Perisphinctoidea. The following is based on Donovan ''et al.'' 1981Donovan, Callomon and Howarth 1981 Classification of the Jurassic Ammonitina; Systematics Association. with modification from the Treatise on Invertebrate Paleontology, Part L (1957) * Perisphinctidae: Middle and Upper Jurassic root stock, derived from the Stephanoceratidae (Middle Jurassic direct derivatives of the Perisphinctidae) * Morphiceratidae * Tulitidae * Reineckeiidae * Pachyceratidae * Aspidoceratidae (early Upper Jurassic (Oxfordian) derivatives of Perisphinctidae) * Aulacostephanidae * Ataxioceratidae (mid Upper Jurassic (Kimmeridgian) derivatives of the Ataxioceratidae) * Dorsoplanitidae * Virgatitidae (late Upper Jurassic (Tithonian) derivatives of Perisphinctidae) * Simoceratidae * Himalayitidae * Olcostephanidae * Holcodiscidae (indirect, from Olcostaphanidae)(now placed in the suberfamily Desmoceratoidea) (Lower Cretaceous Perisphinctoidea (Berriasan - Hauterivien) * Berriasellidae (derived from Ataxioceratidae)(now considered a subfamily of Neocomitidae) * Polytichitidae Craspeditidae">Craspeditidae.html" ;"title="Craspeditidae">Craspeditidae(derived from Dorsoplanitidae) *Neocomitidae (derived from Berriasellidae)(now placed in the superfamily Endemoceratoidea) *Oosterellidae (Hauterivian derivative of the Neocomitidae)

References

Perisphinctoidea, Ammonitina Prehistoric animal superfamilies Bajocian first appearances Early Cretaceous extinctions {{ammonitina-stub