What is "clam shrimp"

n. Any branchiopod crustacean of the suborders ''(taxlink Cyclestherida suborder)'', ''(taxlink Laevicaudata suborder)'', or ''(taxlink Spinicaudata suborder)'' (of the disused superorder ''(taxlink Conchostraca superorder)''), covered by a bivalve shell and well adopted to live in temporary, shallow ponds, with many identified extinct and extant species used to date strata.

Clam shrimp are a taxon of bivalved branchiopod crustaceans that resemble the unrelated bivalved molluscs. They are extant, and known from the fossil record, from at least the Devonian period and perhaps before. They were originally classified in a single order Conchostraca, which later proved to be paraphyletic.