Ephemeral-wetland
Guides
Eulimnadia
clam shrimp
Eulimnadia is a genus of small freshwater branchiopods commonly known as clam shrimp. The genus is notable for its rare androdioecious mating system, where populations consist of males and hermaphrodites but lack pure females. This reproductive strategy has persisted for an estimated 24–180 million years across multiple speciation events, making it one of the most stable examples of androdioecy known in animals. Species are distinguished primarily by the morphology of their resting eggs (cysts), which show distinctive sculpturing patterns. The genus contains approximately 13–25 described species with a cosmopolitan distribution across every continent except Antarctica.
Eulimnadia geayi
Eulimnadia geayi is a small freshwater crustacean in the family Limnadiidae, commonly known as clam shrimp. First described by Eugen von Daday in 1913, this species inhabits temporary aquatic habitats across Central and South America. Like other members of its genus, it produces drought-resistant eggs that survive in dry sediment until rainfall triggers hatching. The species plays a role in ephemeral pool food webs as both a detritivore and prey item.
Lepidurus packardi
Vernal Pool Tadpole Shrimp
Lepidurus packardi is a federally endangered, California endemic freshwater microcrustacean in the order Notostraca. It is an ephemeral wetland specialist restricted to vernal pools and other temporary water bodies. The species is a key food source for larval California Tiger Salamander and acts as an ecosystem engineer through bioturbation. It reaches approximately 5 cm in length with a shield-like carapace up to 3.5 cm long.
Spinicaudata
clam shrimp
Spinicaudata is an infraorder of small, bivalved branchiopod crustaceans commonly known as clam shrimp. They inhabit temporary freshwater pools, saline lakes, and rock holes (gnammas) across arid and semi-arid regions worldwide. The group is characterized by a laterally compressed body enclosed within a hinged, clam-like carapace. Many species produce drought-resistant resting eggs that persist in dry sediments until favorable conditions return. Reproductive modes vary, with some lineages exhibiting androdioecy (hermaphrodites with occasional males) and others gonochorism (separate sexes with ~1:1 ratios).
Streptocephalus
Rams-horn Fairy Shrimps
Streptocephalus is a genus of fairy shrimp (Anostraca) found in temporary freshwater habitats across Africa, Australia, Eurasia, and the Americas. Its distribution reflects an ancient Gondwanan origin. The genus is characterized by distinctive mandibular morphology adapted for processing diverse food sources. Species in this genus are obligate inhabitants of ephemeral aquatic environments, with life cycles synchronized to the temporary nature of their habitats.