Very big flowers in this one

This Mammillaria surprised me with its big flowers.
They are 4,5 centimeters across.

Flowers reminds me of M. deherdtiana but spines doesn't match. The are very stout and robust.

Someone proposed M. melanocentra rubrograndis but I'm not convinced.

With such big flowers I believe it will not be difficult to identify.

Thanks for any help!

The only option I can think of is indeed M. rubrograndis (or M. melanocentra subsp. rubrograndis, if you like). Spination and flowers more or less fit for the very wide-spread rubrograndis. Have a look at Maurillio's pages on the forum for M. melanocentra and scroll down until you see rubrograndis. There are quite a few of my habitat photos there.

Wolter ten Hoeve.

Thank you Wolter.
Well if it is rubrograndis the other one I have posted cannot be. They are very different.
I saw your habitat pictures, very interesting by the way. My plant seems to have bigger flowers but it can be just a variation (?).
Thank you

Have to be satisfied with rubrograndis, but is curious that a such big flowered Mammillaria (which is not common) can be dificult to identify.
Thanks a lot Wolter