Desiccation-resistant-eggs
Guides
Notostraca
tadpole shrimp, shield shrimp
Notostraca is an order of small crustaceans commonly known as tadpole shrimp or shield shrimp. The group contains a single extant family, Triopsidae, with two genera: Triops and Lepidurus. These animals are considered living fossils, with morphologically similar forms dating back to the Late Devonian approximately 360 million years ago. They inhabit temporary freshwater pools, shallow lakes, and similar aquatic environments worldwide except Antarctica.
Triops longicaudatus
Longtail Tadpole Shrimp, American Tadpole Shrimp, Rice Tadpole Shrimp
Triops longicaudatus is a freshwater branchiopod crustacean commonly known as the longtail tadpole shrimp or rice tadpole shrimp. It inhabits ephemeral ponds and pools across western North America, South America, Japan, South Korea, and Pacific Islands. The species is notable for its ancient lineage—morphologically unchanged for over 170 million years—and its remarkable desiccation-resistant eggs that can survive decades in dry sediment before hatching upon rehydration. It displays multiple reproductive strategies including parthenogenesis, hermaphroditism, and sexual reproduction. In California agriculture, it is a significant early-season pest of rice, damaging germinating seeds in flooded fields.