''Xiphactinus'' (from

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

and

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

for "

sword A sword is an edged and bladed weapons, edged, bladed weapon intended for manual cutting or thrusting. Its blade, longer than a knife or dagger, is attached to a hilt and can be straight or curved. A thrusting sword tends to have a straighter ...

-ray") is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus of large predatory 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 ...

that lived during the late

Albian The Albian is both an age (geology), age of the geologic timescale and a stage (stratigraphy), stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early Cretaceous, Early/Lower Cretaceous epoch (geology), Epoch/s ...

to the late

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 ...

. The genus grew up to in length, and superficially resembled a gargantuan, fanged tarpon. It is a member of the extinct order

Ichthyodectiformes Ichthyodectiformes is an Extinction, extinct order of marine stem-teleost ray-finned fish. The order is named after the genus ''Ichthyodectes'', established by Edward Drinker Cope in 1870. Ichthyodectiforms are usually considered to be some of th ...

, which represent close relatives of modern teleosts. The species ''Portheus molossus'' described by Cope is a

junior synonym In taxonomy, the scientific classification of living organisms, a synonym is an alternative scientific name for the accepted scientific name of a taxon. The botanical and zoological codes of nomenclature treat the concept of synonymy differently. ...

of ''X. audax''. Skeletal remains of ''Xiphactinus'' have come from the Carlile Shale and Greenhorn Limestone of

Kansas Kansas ( ) is a landlocked U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the west. Kansas is named a ...

(where the first ''Xiphactinus'' fossil was discovered during the 1850s in the

Niobrara Chalk The Niobrara Formation , also called the Niobrara Chalk, is a Formation (stratigraphy), geologic formation in North America that was deposited between 87 and 82 million years ago during the Coniacian, Santonian, and Campanian stages of the La ...

),''Xiphactinus''
at

Fossilworks Fossilworks was a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world. History Fossilworks was cr ...

.org and Cretaceous formations all over the East Coast (most notably

Georgia Georgia most commonly refers to: * Georgia (country), a country in the South Caucasus * Georgia (U.S. state), a state in the southeastern United States Georgia may also refer to: People and fictional characters * Georgia (name), a list of pe ...

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North Carolina North Carolina ( ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, South Carolina to the south, Georgia (U.S. stat ...

, and

New Jersey New Jersey is a U.S. state, state located in both the Mid-Atlantic States, Mid-Atlantic and Northeastern United States, Northeastern regions of the United States. Located at the geographic hub of the urban area, heavily urbanized Northeas ...

) in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

, as well as

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

, the Kanguk and Ashville Formations of

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

, La Luna Formation of

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

and the

Salamanca Formation The Salamanca Formation is a geologic formation in the Golfo San Jorge Basin of central Patagonia that yields well-preserved, well-dated fossils from the early Paleocene. Studies of these fossils are providing new data on plant and animal diversit ...

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

Paleobiology

Species of ''Xiphactinus'' were voracious predatory fish. At least a dozen specimens of ''X. audax'' have been collected with the remains of large, undigested or partially digested prey in their stomachs. In particular, one fossil "Fish-Within-A-Fish" specimen was collected by George F. Sternberg with another, nearly perfectly preserved long ichthyodectid '' Gillicus arcuatus'' inside of it. The larger fish apparently died soon after eating its prey, most likely owing to the smaller prey's struggling and rupturing an organ as it was being swallowed. This fossil is on display at the Sternberg Museum of Natural History in

Hays, Kansas Hays is a city in and the county seat of Ellis County, Kansas, United States. The largest city in northwestern Kansas, it is the economic and cultural center of the region. As of the 2020 census, the population of the city was 21,116. Hays ...

. Like many other species in the Late Cretaceous oceans, a dead or injured individual was likely to be scavenged by sharks ('' Cretoxyrhina'' and '' Squalicorax''). The remains of a ''Xiphactinus'' were found within a large specimen of '' Cretoxyrhina'' collected by Charles H. Sternberg. The specimen is on display at the University of Kansas Museum of Natural History. Xiphactinus - head detail

Like modern tarpons, ''Xiphactinus'' likely spent its juvenile stage of life in shallow seaway margins for protection and to utilize rich food resources, possibly rare in open marine water, though this needs confirmation due to the lack of shallow, nearshore deposits from the

Western Interior Seaway The Western Interior Seaway (also called the Cretaceous Seaway, the Niobraran Sea, the North American Inland Sea, or the Western Interior Sea) was a large inland sea (geology), inland sea that existed roughly over the present-day Great Plains of ...

. The teeth of the juvenile specimen indicate that the diet of ''Xiphactinus'' probably didn't change notably during its growth, implying that even the small specimens would have been fish-eating predators.

"Unicerosaurus"

In 1982, a former Baptist minister, Carl Baugh, began excavations on the limestone beds of the

Paluxy River The Paluxy River, also known as Paluxy Creek, is a river in the U.S. state of Texas. It is a tributary of the Brazos River. It is formed by the convergence of the ''North Paluxy River'' and the ''South Paluxy River'' near Bluff Dale, Texas in E ...

, near Glen Rose, Texas, famous for its dinosaur tracks. Some of the tracks resembled human footprints and had been proclaimed since 1900 as evidence that dinosaurs and modern humans had once lived alongside one another. Scientists' investigations found the supposed human footprints to be "forms of elongate dinosaur tracks, while others were selectively highlighted erosional markings, and still others (on loose blocks) probable carvings." While excavating, he found a solitary "Y-shaped" fossil that he informally called "Unicerosaurus". In a 1987 popular article, John Armstrong described the fossil as a "Y-shaped petrified bone that appears to be the neural spine from a huge fish like the ''Portheus'' of

" that Baugh's museum "declared to be the forehead horn of a newly discovered dinosaur genus". The museum's exhibit told visitors that the "horn" belonged to "the

unicorn The unicorn is a legendary creature that has been described since Classical antiquity, antiquity as a beast with a single large, pointed, spiraling horn (anatomy), horn projecting from its forehead. In European literature and art, the unico ...

of Job 38, one of three dinosaurs mentioned in Scripture; the others being behemoth and leviathan of Job 40 and 41", and that the horn was able to fold back like the blade of a jack knife. Although some Young Earth Creationists shared Baugh's interpretations of the biblical

Behemoth Behemoth (; , ''bəhēmōṯ'') is a beast from the biblical Book of Job, and is a form of the primeval chaos-monster created by God at the beginning of creation. Metaphorically, the name has come to be used for any extremely large or powerful ...

and

Leviathan Leviathan ( ; ; ) is a sea serpent demon noted in theology and mythology. It is referenced in several books of the Hebrew Bible, including Psalms, the Book of Job, the Book of Isaiah, and the pseudepigraphical Book of Enoch. Leviathan is of ...

, Baugh's claims were not taken seriously either by Christian organizations or the scientific community.

In popular culture

In October 2010, Kansas House Rep. Tom Sloan (R-Lawrence) announced that he would introduce legislation to make ''Xiphactinus audax'', a.k.a. the "X-fish", the state fossil of

. Ultimately, ''

Tylosaurus ''Tylosaurus'' (; "knob lizard") is a genus of Russellosaurina, russellosaurine mosasaur (an extinct group of predatory marine Squamata, lizards) that lived about 92 to 66 million years ago during the Turonian to Maastrichtian stages of the Late ...

'' was selected instead.

Notes

References

External links

BBC

Canadian Fossil Discovery Centre
{{Portal bar, Paleontology, Fish, Marine life Ichthyodectiformes Marine fish genera Prehistoric ray-finned fish genera Late Cretaceous fish of North America Cretaceous Canada Fossils of Canada Cretaceous United States Fossils of the United States Cretaceous fish of Europe Cretaceous fish of Australia Late Cretaceous fish of South America Cretaceous Venezuela Fossils of Venezuela Albian genus first appearances Cenomanian genera Turonian genera Coniacian genera Santonian genera Campanian genera Maastrichtian genus extinctions Demopolis Chalk Mooreville Chalk Fossil taxa described in 1870 Taxa named by Joseph Leidy Cretaceous Argentina Golfo San Jorge Basin Salamanca Formation