Late Pennsylvanian long bone

[connorp]

Not sure if this bone is identifiable whatsoever. It is from the LaSalle Limestone (Late Pennsylvanian) in Illinois. There is not much original bone remaining but there is a decent impression of (at least part of) what is missing. The lack of non-cartilaginous fish from this unit makes me suspect tetrapod (which have been reported), but I'm not sure if this bone can be identified anatomically. Any thoughts are appreciated.

 

[connorp]

[westcoast]

I suspect that is an acanthodian spine