Five subspecies of Phymaturus from Argentine Patagonia are identified: P. patagonicus patagonicus Koslowsky, P. patagonicus indistinctus subsp. nov., both from Chubut, P. patagonicus somuncurensis, subsp. nov. from Rio Negro, P. patagonicus zapaiensis subsp. nov. from Neuquén, and P. patagonicus payuniae subsp. nov. from Southern Mendoza. Their morphological and ecological features are described according to their widespread but isolated distribution. Quantitative immunological analyses emphasize the close affinities of the 5 proposed subspecies and their more distant relationships to P. palluma which is sympatric with P. patagonicus in Mendoza and Neuquén.