They're massive, but C. quercicola is pretty much the same, just black and stubbier legs.
I seen both queens. I think Ca02 is at least 2 millimeters longer than quercicolas. When my queens may them rest in peace. Lolol drink nectar. They would reach 21mm.
I never had Pogonomyrmex colonies. Lots of people like them. A giant species of Pogonomyrmex live 15 minutes away from home. They are a bit shorter than cokerelli workers. maybe 10mm long, but have massive heads. I fear their sting. I always get attacked when handling my colonies. They do lack stingers. Thank god. What are the plus side of having Pogonomyrmex colonies.?