pronormoblast

noun

pro·​nor·​mo·​blast (ˈ)prō-ˈnȯr-mə-ˌblast 

: a cell recognized in some theories of erythropoiesis that arises from a myeloblast and gives rise to normoblasts and is approximately equivalent to the erythroblast of other theories

called also macronormoblast, rubriblast