Uracoan diamondback rattlesnake

It was quite active...

Zootierliste lists 5 species of Rattlesnakes for Madrid ( Dusky pygmy, Cascabel, Sidewinder, Uracoan and Western diamond back rattlesnake ) and I would say the one on the picture is the Western diamondback rattlesnake ( Crotalis atrox ) however not 100 % sure - just 95 % .

I think this is Uracoan rattlesnake.

I agree with Nikola...that's definitely not a Crotalus atrox, but C. (durissus) vegrandis.