Smallest organisms 4.4 cm (1.7 in). The smallest member of the order Carnivora is the least weasel ("Mustela nivalis"), with an average body length of 114–260 mm (4.5-10.2 in). It weighs between 29.5 – 250 grams with females being lighter. The smallest marsupial is the Long-tailed planigale from Australia. It has a body length of (including tail) and weigh on average. The Pilbara ningaui is considered to be of similar size and weight. The smallest member of the primate order is Madame Berthe's mouse lemur ("Microcebus berthae"), found in Madagascar, with an average body length of 92 mm (3.6 in). The smallest
Smallest organisms on the archaeon "Ignicoccus"; it must be in contact with the host organism to survive. Prasinophyte algae of the genus "Ostreococcus" is the smallest free-living eukaryote. The single cell of an "Ostreococcus" measures only 0.8 μm across. Several species of Myxozoa (obligately parasitic cnidarians) never grow larger than 20 µm. One of the smallest species ("Myxobolus shekel") is no more than 8.5 µm when fully grown. The shell of the nut clam "Condylonucula maya" grows only 0.54 mm long. The smallest water snail (of all snails) is "Ammonicera minortalis" in North America, originally described from Cuba. It measures 0.32 to