Stratum.black
Uintacrinus socialis — Uintacrinus (NHMUK PV P 17228 ($))
Uintacrinus (NHMUK PV P 17228 ($)) — © The Trustees of the Natural History Museum, London, Natural History Museum (London) Data Portal, CC BY 4.0

Crinoid

Uintacrinus socialis

Free-floating crinoid

Uintacrinus socialis is the stemless, free-floating crinoid of the Niobrara Chalk, found as slabs where dozens of globular calices and long arms tangle together. Uintacrinus plates are a Kansas speciality and sell from a few hundred dollars for small slabs to five figures for large ones. The chalk is soft, so slabs are consolidated and often backed.

PhylumEchinodermata
ClassCrinoidea
OrderUintacrinida
FamilyUintacrinidae
GroupCrinoid
Rank (PBDB)genus· Paleobiology Database
AuthorGrinnell 1876· Paleobiology Database
Classification (PBDB)Echinodermata › Crinoidea › Comatulida › Uintacrinidae· Paleobiology Database
Range (PBDB)89.8–83.6 Ma· Paleobiology Database
PBDB occurrences4· Paleobiology Database

Photographs

Uintacrinus socialis — Uintacrinus (NHMUK PV P 28652 $1)
Uintacrinus (NHMUK PV P 28652 $1) — © The Trustees of the Natural History Museum, London, Natural History Museum (London) Data Portal, CC BY 4.0

Age

Formations

See also

Elsewhere

Cite this article

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

BibTeX · CSL-JSON

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

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