Coriops is a genus of prehistoric fish. Its fossils are found in Campanian

Campanian

The Campanian is, in the ICS' geologic timescale, the fifth of six ages of the Late Cretaceous epoch . The Campanian spans the time from 83.5 ± 0.7 Ma to 70.6 ± 0.6 Ma ...

 (Mesa Verde Formation), Maastrichtian

Maastrichtian

The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...

 (Hell Creek Formation

Hell Creek Formation

The Hell Creek Formation is an intensely-studied division of Upper Cretaceous to lower Paleocene rocks in North America, named for exposures studied along Hell Creek, near Jordan, Montana...

), and possibly Paleocene

Paleocene

The Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from about . It is the first epoch of the Palaeogene Period in the modern Cenozoic Era...

 (also Hell Creek) age deposits. This chronological distribution means that the genus may have survived the K-T extinction event that killed the dinosaur

Dinosaur

Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

s.

Classification

Sepkoski's compendium of marine fossil genera has it classified as an eel

Eel

Eels are an order of fish, which consists of four suborders, 20 families, 111 genera and approximately 800 species. Most eels are predators...

, but it has been classified in the Elopiformes

Elopiformes

Elopiformes is the order of ray-finned fish that includes the tarpons, tenpounders, and ladyfish, as well as a number of extinct types. They have a long fossil record, easily distinguished from other fishes by the presence of an additional set of bones in the throat.They are related to the order...

 and the Osteoglossomorpha

Osteoglossomorpha

Osteoglossomorpha is a group of bony fish in the Teleostei.-Notable members:A notable member is the Arapaima , the largest freshwater fish in South America and one of the very largest bony fishes alive. Other notable members include the bizarre freshwater elephantfishes .-Systematics:Most...

.