''Archaeus'' is an extinct genus of jackfish from the

Paleogene The Paleogene ( ; British English, also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period, geologic period and system that spans 43 million years from the end of the Cretaceous Period million yea ...

of Europe. The oldest species, ''A. oblongus'' is from the late/terminal Thanetian epoch of Paleocene Turkmenistan, and the last species, ''A. glarisianus'' and possibly ''A. brevis'', are from the early to middle Rupelian, of the

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...

lagerstatten of Canton Glarus,

Switzerland ). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...

. In life, ''Archaeus'' species would have resembled a small

trevally The Carangidae are a family of ray-finned fish which includes the jacks, pompanos, jack mackerels, runners, and scads. It is the largest of the six families included within the order Carangiformes. Some authorities classify it as the only famil ...

, though, ''Archaeus'' had a proportionally smaller mouth, and larger eyes, and the tail was more fan-shaped, rather than crescent-shaped. Archaeus oblongus

References

* Catalogue of the fossil fishes in the British museum (Natural history)''

* PROKOFIEV Artém M. The Late Paleocene fish fauna of Turkmenistan Paleocene fish Eocene fish Oligocene fish Thanetian genus first appearances Rupelian genus extinctions Carangidae Paleogene fish of Europe Paleogene fish of Asia Fossil taxa described in 1834 {{paleo-perciformes-stub