The tadpole shrimp is considered one of the oldest living species on the planet, estimated to be about 500 million years old. It is a natural phenomenon of the oldest animal species that appeared 300 million years before the dinosaurs. Fossils of this type were recorded in the Late Triassic period and they are almost unchanged in their present appearance.
The tadpole shrimp has a very fast life cycle and individuals reach full maturity in about two weeks after hatching. The upper body of some of these species is almost completely covered with a vaulted chitinous plate, which contributes to their archaic appearance. Others resemble small bivalves, where the body lies between two lid-like shells, and some have a completely naked and unprotected body.
They have unusually many leaf-shaped limbs that contribute to breathing, as well as movement. Each limb has numerous fibers that filter nutrients from the water and play an important role in the nutrition of these organisms. In indoor conditions, they usually reach a length of up to 6 cm, and in the wilderness up to 11 cm.
They survive at very low temperatures, during long-lasting droughts and even fires.