This mayfly was found into my city, Zaragoza, in NE Spain, in a river forest (poplars, oxes, etc) The river (Ebro river) is great, deep, slow and contaminated. The picture (sorry by the poor quality) is taked at April. Two cerci, about 2 cm wingspan, veis marked in dark, at least in coastal area.
It's possible to identify? Could be an Ecdyonurus?