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Features of non-crinoid columnals?


mbarco

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I know how Crinoid columnals looks like, but which are the features of other echinoderm classes (Rhombifera, Diploporita,...)?

Image of a crinoid columnal mould (scale bar 5mm).

IMG_20220206_142250.jpg

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I cannot emphasize enough just how useful the Treatise on Invertebrate Paleontology is for questions such as these. You can find hard copies on the secondary market for very reasonable prices. You can also join the Paleontological Society https://www.paleosoc.org/become-a-member for a very reasonable sum and get online access to all volumes of the Treatise

From Part S Echinodermata Volume 1, the Rhombifera and Diploporita are cystoids:

 

image.png.b944dde6b9866d77500142dcae2f3882.png

Description of the Rhombifera:

image.png.25da71b399d275864d1f02eefac43981.png

 

Description of the Diploporita:

image.png.f722aef58fc05f01bcde38edb24ab433.png

Edited by Crusty_Crab
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Trying to read between the lines, if your question is- I found a stem, how can I differentiate between the eocrinoidea, paracrinoidea, cystoidea, blastoidea, parablastoidea, edrioblastoidea and crinoidea? The answer as I understand it is you can't, the differentiation is based on the theca. Without other information such as formation, age, etc., perhaps the best you can say is it belongs to the crinozoa. 

image.png.ba2f5c77b95aea36573afd6da11f50ea.png

 

image.png.9ffeffa238a3170343ef344512ed1eb3.png

image.png.66f383f76964c7b3109e1ed429be808c.png

 

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