''Asthenopsis'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus from a well-known class of fossil marine arthropods, the trilobites. It lived during the

Cambrian Period The Cambrian Period ( ; sometimes symbolized C with bar, Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million ...

, which lasted from approximately 542 to 488 million years ago.

References

Cambrian trilobites of Australia Ptychopariida genera Fossil taxa described in 1939 Ptychopariidae Cambrian genus extinctions {{Ptychopariida-stub