Phylum Loricifera (Brush Heads)
Approximate Number of Species: 80
Largest: Rugiloricus carolinus at a length of 0.02 inches (0.508 mm)
Smallest: Nanaloricus mysticus at a length of 0.0005 inches (0.0114 mm)
References:
Kristensen RM (2004) An introduction to Loricifera, Cycliophora, and Micrognathozoa. Integrative and Comparative Biology 42:641-651.
Higgins RP & Thiel H eds (1988) Introduction to the study of meiofauna (Smithsonian Institute Press, Washington, D.C.).