1) Animal order 2) Living fossil 3) Order notostraca 
The order Notostraca comprises the single family Triopsidae, containing the tadpole shrimp or shield shrimp. The two genera, Triops and Lepidurus, are considered living fossils, having not changed significantly in outward form since the Triassic. They have a broad, flat carapace, which conceals the head and bears a single pair of compound eyes. Th...
[n] - small freshwater crustaceans with a shield-shaped carapace
order Notostraca noun small freshwater crustaceans with a shield-shaped carapace