Cryptobiosis
Guides
Artemia
brine shrimp
Artemia is a genus of aquatic crustaceans commonly known as brine shrimp, the sole genus in the family Artemiidae. The genus comprises both bisexual and parthenogenetic species with considerable variation in salinity and temperature tolerances among populations. Species show ecological isolation based on lakewater chemistry differences, with competitive hierarchies established between sympatric taxa. Artemia has remained morphologically conservative since the Triassic period.
Artemia franciscana
San Francisco brine shrimp
Artemia franciscana is a small crustacean native to hypersaline environments of the Americas, now widely introduced globally for aquaculture. The species exhibits exceptional reproductive plasticity, switching between ovoviviparity (live birth of nauplii) and oviparity (production of dormant cysts) based on environmental conditions. It matures rapidly, reaching reproductive age in under 20 days, and serves as a critical live food source in commercial fish and shellfish farming. The species shows pronounced phenotypic plasticity in response to salinity and temperature stress.
Bdelloidea
Bdelloid rotifers, bdelloids
Bdelloidea is a class of microscopic rotifers found in freshwater habitats worldwide, comprising over 450 described species. These organisms are distinguished by obligate parthenogenetic reproduction—no males have ever been observed—and their remarkable ability to survive extreme desiccation through anhydrobiosis. They range from 150–700 μm in length and can remain dormant for years, with documented cases of revival after 24,000 years frozen in Siberian permafrost. Bdelloids have been called 'ancient asexuals' due to their estimated 25+ million year history of asexual reproduction supported by fossil evidence.
Triopsidae
Tadpole Shrimps, Shield Shrimp
Triopsidae is the sole family in the order Notostraca, commonly known as tadpole shrimps or shield shrimps. These freshwater crustaceans are considered living fossils, with body plans essentially unchanged since the Triassic period. The family contains two genera, Triops and Lepidurus. Members possess a distinctive broad, flat carapace covering the head, a long segmented-appearing abdomen with numerous leg pairs, and compound eyes. Their eggs can survive extended desiccation, enabling populations to persist through drought conditions and hatch when habitats reflood.