| Aethocrinus Temporal range:
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|---|---|
Scientific classification 
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| Kingdom: | Animalia |
| Phylum: | Echinodermata |
| Class: | Crinoidea |
| Family: | †Aethocrinidae |
| Genus: | †Aethocrinus |
Aethocrinus is an early-diverging crinoid reported from the Early Ordovician.1 Its five arms bifurcate.
The contested Echmatocrinus notwithstanding, it is a candidate for the earliest true member of the crinoid class – though not being a member of the crown group, quite where within the stem group to draw the distinction between eocrinoids and crinoids is a somewhat arbitrary decision.
References
References
- Philip, G. M.; Strimple, H. L. (1971). "An Interpretation of the Crinoid Aethocrinus moorei Ubaghs". Journal of Paleontology. 45 (3): 491–493. JSTOR 1302696.