Illusory erect spines(?) on a Kimmswick receptaculitid

[pefty]

UPDATE: These seem to just be weirdly incomplete cross-sections through ordinary cylindrical meroms.

 

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This weekend in the Kimmswick Limestone in eastern Missouri (Pike County) I saw plenty of receptaculitid algae, mostly of genus Fisherites. But one cross-section has a feature I've never seen before: a fringe of what look like erect spines on the external surface. Can someone point me to a reference for understanding this feature functionally and/or taxonomically? I've looked in the usual places but I don't seem to be finding anything about spines.

 

(If I were a vertebrate paleontologist, I would be saying they were feathers and proclaiming receptaculitids' "Sinosauropteryx moment.")

 

Thanks.

 

 

 

Edited October 27, 2021 by pefty
Realized what I was looking at :D