The problem, which should be the solution:
1 central spine and 5 radials all seem short but heavy
bristles instead of wool in the areoles
New spine growth is dark and fades with age
Pink flowers low on the body so on second year growth, not first year
bright green body, not glaucous
Tubercles seem square but with rounded corners

and well packed in
That's all I've got and it doesn't add up to anything at all.
Any sign of dichotomous splitting or offsets?