remain viable for centuries, and the mixing of system sediment results in the hatching of different aged cysts in each generation. This inbreeding slows the rate of selection by resisting gene flow and minimizing phenotypic variation, in turn promoting the stability of the existing, successful phenotype. Anostracans are an important food source for many birds and fish. For example, they provide much of the food for female pintails and mallards in the Prairie Pothole Region of the Great Plains in North America, especially in years when temporary wetlands are abundant. Similarly, Artemia forms an important part of the diet of flamingos wherever it can be found. Uses Brine shrimp are used as food for fish and other organisms in aquaria and aquaculture. Their drought-resistant eggs are collected from lakeshores and are stored and transported dry. They hatch readily when submerged in salt water. This is a multimillion-dollar industry, centred on the Great Salt Lake in Utah and San Francisco Bay in California; adults are collected from Mono Lake and transported frozen. Fossil record and evolution Fairy shrimp are believed to have diverged from the main line of Branchiopoda during the Ordovician period, around the same time it is thought they colonized freshwater and estuarine ecosystems. This transition is believed to have been the result of selection pressure to escape predation in the Early Paleozoic seas. Lepidocaris from the early Devonian Rhynie chert is likely a close relative of Anostraca. The oldest known modern-looking ansotracan is Haltinnaias from the late Devonian (Famennian) Strud locality of Belgium, around 365 million years old. Some studies point to fossils resembling fairy shrimp in the Upper Cambrian, specifically the oldest known branchiopod fossil, Rebachiella kinnekullensis, from Orsten marine deposits. Despite its seeming resemblance to modern fairy shrimp, this fossil is still considered by most to be an outlying member of the ancestral marine Branchiopoda rather than a true fairy shrimp. The monophyly of this order is well supported, and the scientific community has reached consensus that Anostraca was the first group to branch off from the Branchiopoda. The radiation hypothesis championing rapid spread and colonization during the Gondwana fragmentation closely echoes the current distribution of the order. Presently, Anostraca are found on all seven continents. Most of the extant genera have restricted geographical distributions. Only three genera are widespread across the remnants of the former supercontinent Pangaea: Artemia, Branchinella and Branchinecta, while the remaining genera