Shark fin spine?

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I've collected several of what I thought were shark fin spines from a Pennsylvanian age site in Oklahoma, along with teeth, and dermal denticles, but can't find anything online that has holes along the sides of the spine.

Any info would be appreciated.

I've found concretions containing fossils from Edestus, Campodus, Listracanthus, and Petrodus,  if that helps.

 

 

[Carl]

From a paleoichthyologist friend:

 

Probably the basal inserted and unornamented part of a dorsal fin spine. The holes are probably where longitudinal vascular canals open on to the surface. I would expect that in a deeply inserted fin spine.