Thanks for the suggestion of Parodia.
Having now looked at many images of Parodia's I'm thinking this specimen definitely could be one.
P. neoarechavaletae is close but all the images I have viewed don't appear to have helical ribs and the crowns have a mass of upright spines, although of the correct colours.
P. roseolutus again is close but images I have viewed seem to have much shorter spines
Another possibility that has popped up while viewing images is Notocactus. N. roseoluteus also looks pretty close but seems to have more ribs than mine, about 16-17.
My specimen has 13 helical ribs and the crown, although having the white hair/wool, does not have a mass of upright spines.
Are Parodia and Notocactus closely related?
Of course it could be that my specimen is still a juvenile. Or maybe rib count and spines do not give a reliable id?
I guess if it ever flowers it will make ID that much easier.
Any further suggestions or confirmations would be most welcome.
Parodia and Notocactus have been merged by many authorities. N. roseoluteus is the same as P. roseolutus (or roseoluta) or Parodia mammulosa subsp. brasilensis, and I agree it's another possibility. P. neoarechavaletae also falls in the Notocactus group.
Helical ribs can be an individual variation, spines also vary. Flowers will help nail it down, until you see those I'd just call it Parodia sp. (or Notocactus, if you prefer).
