Eocrinoidea

Eocrinoidea Temporal range: Cambrian Stage 3–Silurian PreꞒ Ꞓ O S D C P T J K Pg N
	Eocrinoid holdfasts (Middle Ordovician, Utah)
	Colourful reconstruction of Gogia ojenai
Scientific classification
Kingdom:	Animalia
Phylum:	Echinodermata
Subphylum:	†Blastozoa
Class:	†Eocrinoidea; Jaekel, 1899
Type genus
	†Eocrinus Jaekel 1918; (= †Gogia Walcott 1917)
Groups included
	†Ascocystitida †Ascocystitidae; †Cambrocrinidae; †Rhopalocystidae; †Ridersiidae; ; †Gogiida †Eocrinidae; †Lichenoididae; †Lyracystidae; †Thorntonitidae; †Turbanicystidae; ; †Imbricata †Felbabkacystidae; †Lepidocystidae; ; †Trachelocrinida †Heckerocrinidae; †Trachelocrinidae; ; †Ampheristocystidae; †Cryptocrinitidae; †Lingulocystidae; †Palaeocystitidae; †Rhipidocystidae; incertae sedis †Cigara (?); †Haimacystis; †Ubaghsicystis; ;
Cladistically included but traditionally excluded taxa
	†Rhombifera; †Diploporita; †Paracrinoidea; †Parablastoidea; †Blastoidea; †Coronoidea; Crinoidea (?);

The Eocrinoidea were an extinct class of echinoderms that lived between the Early Cambrian and Late Silurian periods. They are the earliest known group of stalked, brachiole-bearing echinoderms, and were the most common echinoderms during the Cambrian.

The earliest genera had a short holdfast and irregularly structured plates. Later forms had a fully developed stalk with regular rows of plates. They were benthic suspension feeders, with five ambulacra on the upper surface, surrounding the mouth and extending into a number of narrow arms.^[16]^[17]

Phylogeny

Eocrinoids were a paraphyletic group that are seen as the basal stock from which all other blastozoan groups evolved.^[18]

Early evolution

The following cladogram, after Nardin et al. 2017 with slight modifications,^[19] shows the progression of early eocrinoid families, with all other eocrinoid families (including representatives Trachelocrinus and Ridersia) grouped with "derived Blastozoans" as their relationships with each other and with other blastozoans are not addressed.

Lepidocystidae

	Kinzercystis

	Vyscystis

	Lepidocystis

	Akadocrinus

	Gogia

	Sinoeocrinus

	Ubaghsicystis

Eocrinidae

Lichenoides

Lichenoididae

	Trachelocrinus

	Ridersia

	(derived Blastozoa)

Relationships to other groups

Relationships among the eocrinidae and other blastozoan clades are an area of ongoing study. Below are two of many cladograms showing some aspect of eocrinoid paraphyly or polyphyly.

Kinzercystis

	Titanocrinus

	Aethocrinus

Lyracystis

Gogia

Sinoeocrinus

Akadocrinus

Tatonkacystis

Ubaghsicystis

Dibrachicystis

Pleurocystites

Velieuxicystis

	Macrocystella

	Ridersia

Lepidocystids (Eocrinoids)

Crinoids

Eocrinoids

Dibrachicystids (Rhombiferans)

Pleurocystitids (Rhombiferans)

Glyptocystitids (Rhombiferans)

Stalked Cambrian (and select Ordovician) echinoderms, after Zamora & Smith, 2011.^[15] All genera except those bracketed as "Crinoids" are blastozoans.

	Akadocrinus

	Cambrocrinus

Ridersia

Sanducystis

Cystobsastus

Lepadocystis

Echinoencrinites

	Cheirocystella

	Macrocystella

Rhombifera

Lysocystites

	Macurdablastus

	Codaster

Stephanocrinus

Thomacystis

	Caryocrinites

	Hemicosmites

Eocrinoids

Glyptocystitoids (Rhombiferans)

Blastoids

Eublastoids (Blastoids)

Coronoids (Blastoids)

Hemicosmitoids (Rhombiferans)

This cladogram, after Paul et al. 2024, shows several eocrinoids in a polytomy with a clade containing several other blastozoan groups.^[14]

References

^ Ubaghs 1967, p. S477
^ "†class Eocrinoidea Jaekel 1918". Paleobiology Database. Retrieved 27 November 2024.
^ Parsley 2021, p. 975 (Note that this paper mistakenly spells the family "Cambrocystidae" or "Cambrocystitidae" despite it being named after Cambrocrius; the 1993 paper by Dzik and Orłowski that the 2021 paper references as defining the family defines it as "Cambrocrinidae")
^ Dzik & Orłowski 1993, p. 32
^ Sepkoski 2002, p. 272
^ Jell & Sprinkle 2021, p. 6
^ Jell & Sprinkle 2021, p. 19
^ "†order Gogiida Broadhead 1982". Paleobiology Database. Retrieved 27 November 2024.
^ "Imbricata". Interim Register of Marine and Nonmarine Genera. Retrieved 12 October 2025. (Note: Nardin et al. (2017) "discards" Imbricata in favor of "Lepidocystoidae" which appears to be a misspelling of "Lepidocystidae"; the more broadly accepted arrangement and spelling is shown here.)
^ "IRMNG — Ampheristocystidae". Interim Register of Marine and Nonmarine Genera. Retrieved 19 November 2025.
^ Sumrall, Colin D.; Sprinkle, James; Guensburg, Thomas E. (2001). "Comparison Of Flattened Blastozoan Echinoderms: Insights From The New Early Ordovician Eocrinoid Haimacystis Rozhnovi". Journal of Paleontology. 75 (5): 987. doi:10.1666/0022-3360(2001)075<0985:COFBEI>2.0.CO;2.
^ ^a ^b ^c ^d Smith 1984, p. 439
^ Sheffield & Sumrall 2019, p. 746
^ ^a ^b Paul et al. 2024, p. 12–13 (Note: The text groups Sanducystis with eocrinoids as the outgroup, but the paper cited classifies it as a glyptocystitoid; it is shown un-bracketed on this page. Similarly, the text classifies Macurdablastus as a eublastoid, but the cited paper has it as the sister of Eublastoidea; it is shown outside of Eublastoidea on this page.)
^ ^a ^b Zamora & Smith 2011
^ Prothero 2004, p. 324
^ Barnes 1982
^ Smith 1984, p. 439
^ Nardin et al. 2017, p. 680 (Note: This source misspells "Lichenoididae" as "Lichenoidae", contrary to the Treatise on Invertebrate Paleontology, Part S, Echinodermata 1, and incorrectly (per PBDB) and IRMNG) includes Lyracystis in Eocrinidae instead of Lyracystidae; this cladogram shows the more common spellings and placements.)

Works cited

Barnes, Robert D. (1982). Invertebrate Zoology. Philadelphia, PA: Holt-Saunders International. pp. 1007–1008. ISBN 978-0-03-056747-6.
Dzik, Jerzy; Orłowski, Stanisław (1993). "The Late Cambrian eocrinoid Cambrocrinus". Acta Palaeontologica Polonica. 38 (1/2): 21–34.
Jell, Peter A.; Sprinkle, James (2021). "Revision of Whitehouse's eocrinoids Peridionites and Cymbionites, with description of the associated fauna including two new echinoderm genera, lower Middle Cambrian Thorntonia Limestone, northwestern Queensland". Alcheringa: An Australasian Journal of Palaeontology. 45 (1): 1–55. doi:10.1080/03115518.2021.1913512.
Nardin, Elise; Lefebvre, Bertrand; Fatka, Oldřich; Nohejlová, Martina; Kašička, Libor; Šinágl, Miroslav; Szabad, Michal (2017). "Evolutionary implications of a new transitional blastozoan echinoderm from the middle Cambrian of the Czech Republic". Journal of Paleontology. 91 (4): 672–684. Bibcode:2017JPal...91..672N. doi:10.1017/jpa.2016.157.
Parsley, R. L. (2021). "Evolution, Functional Morphology and Paedomorphism in the Gogiid-Ascocystitid Lineage (Eocrinoidea; Cambrian-Ordovician)". Paleontological Journal. 55 (9): 966–976. Bibcode:2021PalJ...55..966P. doi:10.1134/S0031030121090100.
Paul, Christopher R. C.; Lefebvre, Bertrand; Nohejlová, Martina; Zamora, Samuel (2024). "Rhombifera Barrande, 1867, and the origin of the Blastoidea (Echinodermata, Blastozoa)". Spanish Journal of Palaeontology. 39: 90. doi:10.7203/sjp.28729. hdl:10550/118357.
Prothero, D. R. (2004). Bringing Fossils to Life; An Introduction to Paleobiology (2 ed.). New York: The McGraw-Hill companies.
Sepkoski, John J., Jr. (16 September 2002). "A Compendium of Fossil Marine Animal Genera". Bulletins of American Paleontology. 362.{{cite journal}}: CS1 maint: multiple names: authors list (link)
Sheffield, S. L.; Sumrall, C. D. (2019). "The phylogeny of the Diploporita: a polyphyletic assemblage of blastozoan echinoderms". Journal of Paleontology. 93 (4): 740–752. doi:10.1017/jpa.2019.2.
Smith, Andrew B. (1984). "Classification of the Echinodermata". Palaeontology. 27 (3): 431–459.
Ubaghs, Georges (1967). "Eocrinoidea". In Moore, Raymond C. (ed.). Treatise on Invertebrate Paleontology, Part S: Echinodermata 1. Vol. 1. University of Kansas Press. pp. S455–S495. Retrieved 29 October 2024.
Zamora, Samuel; Smith, A. B. (2011). "Cambrian stalked echinoderms show unexpected plasticity of arm construction". Proceedings of the Royal Society B. 279 (1727): 293–298. doi:10.1098/rspb.2011.0777. PMC 3223674. PMID 21653588.

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[1] Ubaghs 1967, p. S477

[2] "†class Eocrinoidea Jaekel 1918". Paleobiology Database. Retrieved 27 November 2024.

[3] Parsley 2021, p. 975 (Note that this paper mistakenly spells the family "Cambrocystidae" or "Cambrocystitidae" despite it being named after Cambrocrius; the 1993 paper by Dzik and Orłowski that the 2021 paper references as defining the family defines it as "Cambrocrinidae")

[4] Dzik & Orłowski 1993, p. 32

[5] Sepkoski 2002, p. 272

[6] Jell & Sprinkle 2021, p. 6

[7] Jell & Sprinkle 2021, p. 19

[8] "†order Gogiida Broadhead 1982". Paleobiology Database. Retrieved 27 November 2024.

[9] "Imbricata". Interim Register of Marine and Nonmarine Genera. Retrieved 12 October 2025. (Note: Nardin et al. (2017) "discards" Imbricata in favor of "Lepidocystoidae" which appears to be a misspelling of "Lepidocystidae"; the more broadly accepted arrangement and spelling is shown here.)

[10] "IRMNG — Ampheristocystidae". Interim Register of Marine and Nonmarine Genera. Retrieved 19 November 2025.

[11] Sumrall, Colin D.; Sprinkle, James; Guensburg, Thomas E. (2001). "Comparison Of Flattened Blastozoan Echinoderms: Insights From The New Early Ordovician Eocrinoid Haimacystis Rozhnovi". Journal of Paleontology. 75 (5): 987. doi:10.1666/0022-3360(2001)075<0985:COFBEI>2.0.CO;2.

[smith1984-12] Smith 1984, p. 439

[13] Sheffield & Sumrall 2019, p. 746

[paul2024-14] Paul et al. 2024, p. 12–13 (Note: The text groups Sanducystis with eocrinoids as the outgroup, but the paper cited classifies it as a glyptocystitoid; it is shown un-bracketed on this page. Similarly, the text classifies Macurdablastus as a eublastoid, but the cited paper has it as the sister of Eublastoidea; it is shown outside of Eublastoidea on this page.)

[zs2011-15] Zamora & Smith 2011

[16] Prothero 2004, p. 324

[IZ-17] Barnes 1982

[18] Smith 1984, p. 439

[nardin2017-19] Nardin et al. 2017, p. 680 (Note: This source misspells "Lichenoididae" as "Lichenoidae", contrary to the Treatise on Invertebrate Paleontology, Part S, Echinodermata 1, and incorrectly (per PBDB) and IRMNG) includes Lyracystis in Eocrinidae instead of Lyracystidae; this cladogram shows the more common spellings and placements.)

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Eocrinoidea Temporal range: Cambrian Stage 3–Silurian PreꞒ Ꞓ O S D C P T J K Pg N

Eocrinoid holdfasts (Middle Ordovician, Utah)

Colourful reconstruction of Gogia ojenai
Scientific classification
Kingdom:	Animalia
Phylum:	Echinodermata
Subphylum:	†Blastozoa
Class:	†Eocrinoidea Jaekel, 1899
Type genus
†Eocrinus Jaekel 1918^[1] (= †Gogia Walcott 1917)
Groups included^[2]
†Ascocystitida †Ascocystitidae †Cambrocrinidae^[3]^[4] †Rhopalocystidae †Ridersiidae^[5] †Gogiida †Eocrinidae †Lichenoididae^[6] †Lyracystidae †Thorntonitidae^[7] †Turbanicystidae^[8] †Imbricata^[9] †Felbabkacystidae †Lepidocystidae †Trachelocrinida †Heckerocrinidae †Trachelocrinidae †Ampheristocystidae^[10] †Cryptocrinitidae †Lingulocystidae †Palaeocystitidae †Rhipidocystidae incertae sedis †Cigara (?) †Haimacystis^[11] †Ubaghsicystis
Cladistically included but traditionally excluded taxa
†Rhombifera^[12] †Diploporita^[12] †Paracrinoidea^[12] †Parablastoidea^[13] †Blastoidea^[12] †Coronoidea^[14] Crinoidea (?)^[15]

Epstein Files Full PDF

Phylogeny

Early evolution

Relationships to other groups

References

Works cited