Triopos

Triopos is a genus of ray-finned fish belonging to the family Triodontidae. The sole living species in this family is Triops cancroides, commonly known as the three-eyed shrimp or tadpole shrimp. Despite its common name, it is not a shrimp but a branchiopod crustacean, more closely related to fairy shrimp and water fleas. Triops cancroides is an ancient lineage, with fossils dating back to the Devonian period, suggesting it has changed very little over millions of years. It is found in freshwater habitats across the globe, typically in temporary pools and ponds that fill with rainwater.

The name "Triops" derives from the Greek words "treis" meaning three and "ops" meaning eye, referring to the three eyes the creature possesses: two compound eyes and a single median dorsal eye. This median eye is sensitive to light intensity and is believed to aid in regulating its circadian rhythm and possibly in detecting predators from above. Triops cancroides has a flattened, shield-like carapace that covers its head and thorax, with a segmented abdomen and a forked tail. They are detritivores, feeding on algae, small invertebrates, and decaying organic matter. Their eggs are remarkably resilient, capable of surviving desiccation for decades, allowing them to hatch when favorable conditions return to their ephemeral habitats. This remarkable survival strategy has contributed to their widespread distribution and long evolutionary history.