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Eutrephoceras — Eutrephoceras
Eutrephoceras — G. Steinmann, Wikimedia Commons, Public domain (US)

Nautiloid

Eutrephoceras

Cretaceous nautiloid

Eutrephoceras is the smooth, globular Cretaceous–Paleogene nautiloid found with the ammonites of the Pierre Shale, Fox Hills and Gulf Coast greensands, distinguished from ammonites by its simple, gently curved sutures. Steinkerns and shelled specimens from South Dakota are sold as 'nautilus' and are cheaper than comparable ammonites. Iridescent examples occur in the same concretions as Placenticeras.

PhylumMollusca
ClassCephalopoda
OrderNautilida
FamilyNautilidae
GroupNautiloid
Rank (PBDB)genus· Paleobiology Database
AuthorHyatt 1894· Paleobiology Database
Classification (PBDB)Mollusca › Cephalopoda › Nautilida › Nautilidae· Paleobiology Database
Range (PBDB)180–11.6 Ma· Paleobiology Database
PBDB occurrences444· Paleobiology Database

Photographs

Eutrephoceras — Eutrephoceras darupense (Schlüter, 1876) (NHMUK PI OR 30212)
Eutrephoceras darupense (Schlüter, 1876) (NHMUK PI OR 30212) — © The Trustees of the Natural History Museum, London, Natural History Museum (London) Data Portal, CC BY 4.0
Eutrephoceras — Eutrephoceras centralis (J. Sowerby, 1812) (NHMUK PI OR 43845)
Eutrephoceras centralis (J. Sowerby, 1812) (NHMUK PI OR 43845) — © The Trustees of the Natural History Museum, London, Natural History Museum (London) Data Portal, CC BY 4.0
Eutrephoceras — Eutrephoceras centralis (J. Sowerby, 1812), FIGURED (NHMUK PI C 6853)
Eutrephoceras centralis (J. Sowerby, 1812), FIGURED (NHMUK PI C 6853) — © The Trustees of the Natural History Museum, London, Natural History Museum (London) Data Portal, CC BY 4.0

Age

Formations

Elsewhere

Cite this article

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

BibTeX · CSL-JSON

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

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