Members of the order Notostraca (colloquially referred to as notostracans, tadpole shrimp, shield shrimp or by the genus name Triops) are small crustaceans in the class Branchiopoda. Triops have two compound eyes and one naupliar eye in between, a flattened carapace covering its head and leg-bearing segments of the body. The order contains a single family, with only two extant genera. Their external morphology has apparently not changed since the Triassic appearance of Triops cancriformis around 220 million years ago. Triops cancriformis may therefore be the “oldest living animal species on earth”.[1] The members of the extinct order Kazacharthra are closely related, having been descended from notostracans.

Triops have been marketed as a novelty pet, given that they can hatch from dried eggs in a similar fashion as Sea-Monkeys.