''Ampheristus'' is an extinct genus of prehistoric marine

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...

. It was a basal or stem member of the family

Ophidiidae The cusk-eel family, Ophidiidae, is a group of marine bony fishes in the Ophidiiformes order. The scientific name is from the Greek ''ophis'' meaning "snake", and refers to their eel-like appearance. True eels diverged from other ray-finned ...

, which contains modern

cusk-eels The cusk-eel family, Ophidiidae, is a group of marine bony fishes in the Ophidiiformes order. The scientific name is from the Greek ''ophis'' meaning "snake", and refers to their eel-like appearance. True eels diverged from other ray-finn ...

. Fossils are known from worldwide (the United States, Europe, India, and New Zealand) from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

to the late

Paleogene The Paleogene Period ( ; also spelled Palaeogene or Palæogene) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period Ma (million years ago) to the beginning of the Neogene Period Ma. It is the fir ...

(

Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...

Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...

), making it a rather successful survivor of the Cretaceous-Paleogene extinction event. It is one of the oldest known members of the order

Ophidiiformes Ophidiiformes is an order of ray-finned fish that includes the cusk-eels (family Ophidiidae), pearlfishes (family Carapidae), viviparous brotulas (family Bythitidae), and others. Members of this order have small heads and long slender bodies. ...

alongside '' Pastorius'' from the Maastrichtian of Italy. Only the type species, ''A. toliapicus'' from the

London Clay The London Clay Formation is a Sediment#Shores and shallow seas, marine formation (geology), geological formation of Ypresian (early Eocene Epoch, c. 54-50 million years ago) age which outcrop, crops out in the southeast of England. The London C ...

, is known from body fossils; the rest are known only by the genus's distinctive

otoliths An otolith (, ' ear + , ', a stone), also called otoconium, statolith, or statoconium, is a calcium carbonate structure in the saccule or utricle of the inner ear, specifically in the vestibular system of vertebrates. The saccule and utricle, i ...

Species

The following species are known: * ''A. americanus'' Schwarzhans & Stringer, 2020 (Maastrichtian of

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

and

Maryland Maryland ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic region of the United States. It borders the states of Virginia to its south, West Virginia to its west, Pennsylvania to its north, and Delaware to its east ...

Danian The Danian is the oldest age or lowest stage of the Paleocene Epoch or Series, of the Paleogene Period or System, and of the Cenozoic Era or Erathem. The beginning of the Danian (and the end of the preceding Maastrichtian) is at the Cretac ...

Arkansas Arkansas ( ) is a landlocked state in the West South Central region of the Southern United States. It borders Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, Texas to the southwest, and Oklahoma ...

) * ''A. bavaricus'' (Koken, 1891) (Maastrichtian of Germany) * ''A. bhavnagarensis'' Singh, Patel & Rana, 2017 (Eocene of India) * ''A. brevicauda'' Schwarzhans, 2010 (Maastrichtian of Germany) * ''A. brevicaudatus'' Lin, Steurbaut & Nolf, 2024 (Eocene of

Alabama Alabama ( ) is a U.S. state, state in the Southeastern United States, Southeastern and Deep South, Deep Southern regions of the United States. It borders Tennessee to the north, Georgia (U.S. state), Georgia to the east, Florida and the Gu ...

Virginia Virginia, officially the Commonwealth of Virginia, is a U.S. state, state in the Southeastern United States, Southeastern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States between the East Coast of the United States ...

and Maryland) * ''A. neobavaricus'' Schwarzhans, 2012 (

Paleocene The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), ...

of Germany) * ''A. pentlandensis'' Schwarzhans, 2019 (Eocene of

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

) * ''A. sinuocaudatus'' Schwarzhans, 1980 (Eocene of New Zealand) * ''A. sztrakosi'' Nolf & Steurbaut, 2004 (Oligocene of Italy) * ''A. toliapicus'' König, 1825 (Eocene of the United Kingdom) (

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

) * ''A. traunensis'' Schwarzhans, 2010 (Maastrichtian of Germany) The species ''A. lerichei'', known by a body fossil from the

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

Belgium Belgium, officially the Kingdom of Belgium, is a country in Northwestern Europe. Situated in a coastal lowland region known as the Low Countries, it is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeas ...

and otoliths from the same region, is alternately placed in ''Ampheristus'' or '' Hoplobrotula''.

References

Prehistoric ray-finned fish genera Ophidiidae Late Cretaceous fish of North America Cretaceous fish of Europe Paleogene fish of Europe Eocene fish of Asia Cenozoic fish of Oceania Fossils of England Fossils of Germany Fossils of Italy Fossils of the United States Fossils of Texas Fossils of New Zealand Fossils of India Maastrichtian genus first appearances Danian genera Selandian genera Ypresian genera Lutetian genera Bartonian genera Rupelian genus extinctions Fossil taxa described in 1825 {{ophidiiformes-stub Taxa named by Charles Konig