The best-preserved compound eyes from the Cambrian Period are found in the trilobites.
These included the trilobites (which became extinct at the end of the Permian), rugose corals, and sponges.
The subsequent adaptive radiation of the trilobites was exceptional, and their remains dominate most later Cambrian deposits.
Compound eyes probably evolved independently in the chelicerata (genus Limulus), the trilobites, and the myriapods (genus Scutigera).
Up to 95% of known species, including the last of the trilobites, disappeared during the extinction.
Through Cambrian times, there is progressive improvement in the trilobites' developmental systems, so that by post-Cambrian times, many families of trilobites have fixed thoracic segment number.
The oldest eyes in the fossil record are compound eyes; specifically, those of the trilobites.
The trilobites lived at high latitudes close to the South Pole during the Ordovician Period.
Ancient arthropods like the trilobites and their neighbors were soon overwhelmed by new legions of shelled beings in the sea.
Climate was warm and invertebrates, such as the trilobites, were abundant.
