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
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]

(Middle Jurassic direct derivatives of the Perisphinctidae)

(early Upper Jurassic (Oxfordian) derivatives of Perisphinctidae)

(mid Upper Jurassic (Kimmeridgian) derivatives of the Ataxioceratidae)

  • Dorsoplanitidae
  • Virgatitidae

(late Upper Jurassic (Tithonian) derivatives of Perisphinctidae)

(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)
gollark: Options are just monoids in the category of endofunctors.
gollark: mildly nicer.
gollark: This would be mk
gollark: You could have a single `f: &dyn Fn(u64, u64) -> Option<u64>`.
gollark: `f:&dyn Fn(u64,u64)->u64, cond:&dyn Fn(u64, u64)->bool` - this is not very idiomatic, consider using `Option`.

References
  1. Arkell, W.J.; Kummel, B.; Wright, C.W. (1957). Mesozoic Ammonoidea. Treatise on Invertebrate Paleontology, Part L, Mollusca 4. Lawrence, Kansas: Geological Society of America and University of Kansas Press.
  2. Donovan, Callomon and Howarth 1981 Classification of the Jurassic Ammonitina; Systematics Association. "Archived copy" (PDF). Archived from the original (PDF) on 2011-07-16. Retrieved 2010-11-20.CS1 maint: archived copy as title (link)
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