Species: Vernal pool tadpole shrimp (Lepidurus packardi)
Status: Endangered (EN)
Interesting Fact: The vernal pool tadpole shrimp is considered a ‘living fossil’, having maintained its well-adapted body characteristics for millions of years
The vernal pool tadpole shrimp is a freshwater crustacean found in temporary pools of the Central Valley of California, USA. These pools are typically dry for seven to eight months of the year. This freshwater species survives through these dry periods as drought-resistant eggs embedded in the top layers of sediment. Most hatch when the pool refills in the next rainy season, although they can remain dormant for up to ten years.
A large, shield-like shell, or carapace, covers most of its 30 to 35 pairs of legs (known as phyllopods). These legs beat in a wave-like motion and propel the shrimp through the water. They also collect food, which consists of detritus, vegetation and other aquatic invertebrates. Few predators inhabit the temporary pools, and so this species has evolved no defences.
The main threat to the vernal pool tadpole shrimp is the continued loss of its habitat to agricultural and urban development. In 2003 it was estimated that only nine percent of the vernal pool habitat in California’s Central Valley remained. The U.S Fish and Wildlife Service (FWS) gives the vernal pool tadpole shrimp protection, meaning any projects which could directly or indirectly affect the vernal pool tadpole shrimp must first obtain a permit from the FWS.
Find out more about the vernal pool tadpole shrimp on the FWS website.
See photos of the vernal pool tadpole shrimp on ARKive.
Lauren Pascoe, ARKive Media Researcher