I can say for certain that this is NOT M. lasiascantha. I have owned many in the past and this isn't one. M. lasiascantha is very compact and it is difficult to see any green through the spines. The pectinate spines are similar, but not nearly dense enough. Here are pictures of M. magallanii. It's been elevated to species rather than a subspecies or variant of M. lasiascantha. (depending on who you listen to)

Probably a M. baumii or related (M. spherica). If it has a yellow flower it is probably M. baumii or one of the other Dolichothele species. If not, let us know. Here are some pictures of M. baumii.

Besides the spines your plant has rounded, flabby areoles which is a key feature of the Dolichothele group. (M. longimamma, M. spherica, etc)

M. lasiascantha is somewhat rare in collections, you won't find one in a big box store. Did you buy this from a specialty cactus seller?

Nice plant!

I can say for certain that this is NOT M. lasiascantha. I have owned many in the past and this isn't one. M. lasiascantha is very compact and it is difficult to see any green through the spines. The pectinate spines are similar, but not nearly dense enough. Here are pictures of M. magallanii. It's been elevated to species rather than a subspecies or variant of M. lasiascantha. (depending on who you listen to)

Probably a M. baumii or related (M. spherica). If it has a yellow flower it is probably M. baumii or one of the other Dolichothele species. If not, let us know. Here are some pictures of M. baumii.

Besides the spines your plant has rounded, flabby tubercles which is a key feature of the Dolichothele group. (M. longimamma, M. spherica, etc)

M. lasiascantha is somewhat rare in collections, you won't find one in a big box store. Did you buy this from a specialty cactus seller?

Nice plant!