M.parkinsonii.

C.peruvianus was what I thought when I first saw it. I'm sure others will give their opinions.

Looks like M.matanzanus to me , but I've been fooled before. The new one just looks more plump than the one on the right . Melos can be difficult to id.

Welcome to the forum Pablo! What an amazing collection you have.

Amazing cactus and flowers Dave , and beautifully photographed too!

I don't see a photo.

Looks like Echinopsis eyresii to me.

#3 is Cliestocactus winteri I think.

I agree with teo.

Thanks Vipassana, adding character is a good way to look at it. Also good evidence of a healthy root system!

I noticed this yesterday afternoon. This Denmoza rhodacantha had an almost unblemished skin, until this happened. Apparently the new soil mix I put it in a month ago has really helped the roots absorb water . I'll have to adjust my watering since I added coir to the soil. I like the new soil mix, bu...

Already a victim! This small Gymno.bruchii got scorched 2 days ago, even with afternoon shade.
I hope it will survive. I'll have to keep a close eye on all the plants through this heat wave.

In a 3 inch pot

E.terscheckii seems like a safe bet. I bought one myself a few years ago thinking it was a Melo.

The spines remind of Mamm. karwinskiana.

That is hot Dave! By the way ,thanks for sending all the rain ! We had a great precipitation year with lots of rain here and snow in the mountains.
I'm curious if there are any cacti species that actually thrives in extreme heat .