Perisphinctes — Perisphinctes
Perisphinctes Masur, Wikimedia Commons, CC BY SA 3.0

Ammonoid

Perisphinctes

Ribbed ammonite

Perisphinctes is the evolute, evenly ribbed Oxfordian ammonite of Madagascar, England and France; Madagascan Perisphinctes with their limestone matrix and ribbed shells are the standard 'Jurassic ammonite' of gift shops. Large specimens (20 cm and up) are polished across one face to show the chambers. Many 'Perisphinctes' are other perisphinctids, but the name works as a trade label.

PhylumMollusca
ClassCephalopoda
OrderAmmonitida
FamilyPerisphinctidae
GroupAmmonoid
Rank (PBDB)genus· Paleobiology Database
Author(Waagen 1869)· Paleobiology Database
Classification (PBDB)Mollusca › Cephalopoda › Ammonitida › Perisphinctidae· Paleobiology Database
Range (PBDB)165–141 Ma· Paleobiology Database
PBDB occurrences495· Paleobiology Database

Elsewhere

Cite this article

Stratum Study. "Perisphinctes" (Taxon). Stratum Study pack 2026.09, as of 2026-09-19. https://stratum.black/study/taxa/perisphinctes. Accessed 2026-09-20.

@misc{stratum-perisphinctes,
  title        = {Perisphinctes},
  author       = {{Stratum Study}},
  howpublished = {\url{https://stratum.black/study/taxa/perisphinctes}},
  year         = {2026},
  note         = {Taxon article, Stratum Study pack 2026.09, as of 2026-09-19; sources: stratum, pbdb, wikidata, commons. Accessed 2026-09-20.}
}

Citations carry the pack version and the article's as-of date so they resolve to the same text later. The facts themselves belong to the sources listed below; cite those for the science.