Jovan Hadži theories of animal evolution. He devised a system of classification in which he divided the animal kingdom into six phyla: Protozoa, Parazoa, "Ameria" (animals with no segments), "Oligomeria" (animals with few segments), "Polymeria" (animals with many segments) and Chordata. His choice of characters important for classification was generally discredited by his contemporaries, and the system was never accepted by zoologists. However, due to its simplicity, the system was widely used in science education in former Yugoslavia. His other major theory was that of the origin of metazoa - he developed an existing hypothesis stating that the first multicellular animals resembling
Bacterial phyla Group A. Two species of the candidate phylum OP10, which is now called Armatimonadetes, where recently cultured: "Armatimonas rosea" isolated from the rhizoplane of a reed in a lake in Japan and "Chthonomonas calidirosea" from an isolate from geothermally heated soil at Hell's Gate, Tikitere, New Zealand. One species, "Caldisericum exile", of the candidate phylum OP5 was cultured, leading to it being named Caldiserica. The candidate phylum VadinBE97 is now known as Lentisphaerae after "Lentisphaera araneosa" and "Victivallis vadensis" were cultured. More recently several candidate phyla have been given provisional names despite the fact that they have no cultured representatives: