Eocrinoidea

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.

Phylum:Echinodermata

Subphylum:†Blastozoa

Class:†Eocrinoidea
Jaekel, 1899

Quick facts Scientific classification, Type genus ...

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]

Close

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]