Help...Sierra Madre Occidental specie

Hello, i'm conducting a study in the Sierra Madre Occidental Region, from Sonora State, Mexico, but i have problems to identify this ejemplar´s...can you help me?..thanks...

Habitat: Oak forest.
Association: Echinocereus pectinatus
Nolina microcarpa
Mimosa dysocarpa
Arcthostaphylos pungen
Quercus emoryi
Q. oblongifolia
Q. toumeyi
Juniperus deppeana
Yucca arizonica
Prosopis velutina
and Dasylirion wheele

https://s1128.photobucket.com/albums/m496/biolvictorvargas/

I don't recognise the plant as a Mammillaria, but I think that it is Coryphantha recurvata. I haven't seen it in Sonoroa, although I haven't travelled widely in that state, just from Chihuahua to Yecora to Hermosillo, to Bahia San Carlos, and then south.
But I have seen this plant just over the border in Arizona USA, to the west of Nogales, and it doesn;t grow much further north, so I am sure it would be found in northern Sonora.

Ok very thanks...normally i'm work with species of Gulf of Mexico Coast and Sierra Madre Oriental region, but this time I had the opportunity to visit the region to review the species of the Sierra de Mariquita and really is quite fascinating how they can coexist under environmental conditions normally we own unique for Pinaceae or Fagaceae Family, and yet the Cactaceae family is present. .. thanks for the help, if you think it's C. recurvata ... thanks ...

Sorry by my bad english

It certainly is a Coryphantha, because you can clearly see a groove on the tubercles in some of the photos (e.g. photo 13).

Wolter.