Perisphinctoidea

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.^[1]

Perisphinctoidea Temporal range: Bajocian–Barremian PreꞒ Ꞓ O S D C P T J K Pg N
Idoceras balderum
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	†Ammonoidea
Order:	†Ammonitida
Suborder:	†Ammonitina
Superfamily:	†Perisphinctoidea Steinmann, 1890
Families
See text
Synonyms
Perisphinctaceae

Classification

Some 16 families have been recognized in the Perisphinctoidea. The following is based on Donovan et al. 1981^[2] with modification from the Treatise on Invertebrate Paleontology, Part L (1957)^[1]

• 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] (derived from Dorsoplanitidae)
• Neocomitidae (derived from Berriasellidae)(now placed in the superfamily Endemoceratoidea)
• Oosterellidae (Hauterivian derivative of the Neocomitidae)