The longtail tadpole shrimp (Triops longicaudatus) is a freshwater
crustacean resembling a miniature
horseshoe crab. It is one of the oldest animal species still in existence. Like its relative Triops cancriformis, the longtail tadpole shrimp is considered a
living fossil because its basic prehistoric
morphology has changed little in the last 70 million years, exactly matching ancient fossils.Photo:
Micha L. Rieser