Perisphinctoidea, formerly Perisphinctaceae, is a superfamily of Middle Jurassic (Bajocian) to Lower Cretaceous (Barremian) ammonites, 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) Morphoceratidae 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] (derived from Dorsoplanitidae) Neocomitidae (derived from Berriasellidae)(now placed in the superfamily Endemoceratoidea) Oosterellidae (Hauterivian derivative of the Neocomitidae)
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