Ephemeral-pool-inhabitant
Guides
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.