In 1993, Cavalier-Smith divided the kingdom Protozoa into two subkingdoms and 18 phyla.[9] By 2003 he used phylogenic evidence to revise the total number of proposed phyla down to 11: Amoebozoa, Choanozoa, Cercozoa, Retaria, Loukozoa, Metamonada, Euglenozoa, Percolozoa, Apusozoa, Alveolata, Ciliophora, and Miozoa. [17]