 Johann Georg Wagler gave the species its current binomial name in 1832 when he erected the new genus Eudocimus , whose only other species is the scarlet ibis ( E. ruber ) . There has long been debate on whether the two should be considered subspecies or closely related species , and the American Ornithologists ' Union considers the two to be a superspecies as they are parapatric . The lack of observed hybrids was a large factor in the view that the species were separate . 
