Mammillaria odehnalii

I got this seed from an Australian seller, and he told me that he had been sent it by a Czech enthusiast, but he said he couldn;t remember who. ''
I researched the name a bit, and discovered that the plant was found by J. Halda at a height of 1400m, near San Juan del Mimbre, in Nuevo Leon. It has the collection number of JJH 850488.

The plant below is now just 2 years old from sowing, and to me it looks as though it ought to be a form of Mammillaria pilispina. This is possible based on where the plant comes from, or maybe it is the form known as M. rayonensis. What do others think?

I think that there are some differences, at this age, the plant has from one to three central spines that are a little bit darker than the description of M. pilipsina suggests. The radial spines are flimsy, but not as hair-like as my M. pilispina SB822. However they are nowhere near as strong as the radial spines of any of my plants of Mammillaria picta, which is probably M. pilispina's closest relative.

It is shown in a 2" (5cm) pot, so it is only about 1" (2.5cm) across at the moment.