The monera are the smallest of living things. They are one-celled with a very simple cellular structure (no cell nucleus or organelles). Examples of monera are bacteria and cyanobacteria. There is no known record of species of monera under threat of extinction.
The taxonomy of this group of organisms is strongly debated and has various fomrats, depending partly on the perspective of the taxonomist (biology, medicine, sedimentology, archaelogy, genetics etc).