''Xiphactinus'' (from

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

and

Greek Greek may refer to: Greece 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 ...

for "

sword A sword is an 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 blade with a pointed tip ...

-ray") 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 of large (Shimada, Kenshu, and Michael J. Everhart. "Shark-bitten Xiphactinus audax (Teleostei: Ichthyodectiformes) from the Niobrara Chalk (Upper Cretaceous) of Kansas." The Mosasaur 7 (2004): 35-39.) predatory marine

bony fish Osteichthyes (), popularly referred to as the bony fish, is a diverse superclass of fish that have skeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes, which have skeletons primarily composed of cartilag ...

that lived during the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger 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 ''creta'', the ...

(

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 ...

Maastrichtian The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval from ...

). Species in the genus bore a superficial resemblance to a gargantuan, fanged

tarpon Tarpons are fish of the genus ''Megalops''. They are the only members of the family Megalopidae. Of the two species, one (''M. atlanticus'') is native to the Atlantic, and the other (''M. cyprinoides'') to the Indo-Pacific Oceans. Species and ...

. The species ''Portheus molossus'' described by Cope is a

junior synonym The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linnae ...

of ''X. audax''. Skeletal remains of ''Xiphactinus'' have come from the

Carlile Shale The Carlile Shale is a Turonian age Upper/Late Cretaceous series shale geologic formation in the central-western United States, including in the Great Plains region of Colorado, Kansas, Nebraska, New Mexico, North Dakota, South Dakota, and Wy ...

and Greenhorn Limestone of

Kansas Kansas () is a state in the Midwestern United States. Its capital is Topeka, and its largest city is Wichita. Kansas is a landlocked state bordered by Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the w ...

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

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

),''Xiphactinus''
at

Fossilworks Fossilworks is 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 crea ...

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

Georgia Georgia most commonly refers to: * Georgia (country), a country in the Caucasus region of Eurasia * Georgia (U.S. state), a state in the Southeast United States Georgia may also refer to: Places Historical states and entities * Related to the ...

Alabama (We dare defend our rights) , anthem = " Alabama" , image_map = Alabama in United States.svg , seat = Montgomery , LargestCity = Huntsville , LargestCounty = Baldwin County , LargestMetro = Greater Birmingham , area_total_km2 = 135,7 ...

North Carolina North Carolina () is a state in the Southeastern region of the United States. The state is the 28th largest and 9th-most populous of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, Georgia and S ...

, and

New Jersey New Jersey is a state in the Mid-Atlantic and Northeastern regions of the United States. It is bordered on the north and east by the state of New York; on the east, southeast, and south by the Atlantic Ocean; on the west by the Delaware ...

) in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territo ...

, as well as Europe, Australia, the Kanguk and Ashville Formations of Canada, La Luna Formation of

Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in t ...

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 diversi ...

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

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 ''Gillicus'' was a relatively small, 2-metre long ichthyodectiform fish that lived in the Western Interior Seaway, in what is now central North America, during the Late Cretaceous. Description Like its larger relative, '' Ichthyodectes cteno ...

'' 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. It is ...

. Like many other species in the Late Cretaceous oceans, a dead or injured individual was likely to be scavenged by sharks (''

Cretoxyrhina ''Cretoxyrhina'' (; meaning 'Cretaceous sharp-nose') is an extinct genus of large mackerel shark that lived about 107 to 73 million years ago during the late Albian to late Campanian of the Late Cretaceous. The type species, ''C. mantelli'', is ...

'' and ''

Squalicorax ''Squalicorax'', commonly known as the crow shark, is a genus of extinct lamniform shark known to have lived during the Cretaceous period. The genus had a global distribution in the Late Cretaceous epoch. Multiple species within this genus are c ...

''). The remains of a ''Xiphactinus'' were found within a large specimen of ''

'' collected by Charles H. Sternberg. The specimen is on display at the University of Kansas Museum of Natural History. Virtually nothing is known about the larval or juvenile stages. The smallest fossil specimen of ''X. audax'' consists of a tooth-bearing

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has b ...

and lower jaws of an individual estimated to be about long. The species and all other ichthyodectids became extinct near the end of the

– see

Cretaceous–Paleogene extinction event The Cretaceous–Paleogene (K–Pg) extinction event (also known as the Cretaceous–Tertiary extinction) was a sudden mass extinction of three-quarters of the plant and animal species on Earth, approximately 66 million years ago. With th ...

. An incomplete

skull The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, th ...

of what may be a new species of ''Xiphactinus'' was found in 2002 in the Czech Republic, in a small town called Šachov next to Borohrádek city, by then 16-year-old student Michal Matějka. In July 2010 the bones of a ''Xiphactinus'' were discovered near Morden, Manitoba, Canada. The specimen was about long and was found with the flipper of a

mosasaur Mosasaurs (from Latin ''Mosa'' meaning the 'Meuse', and Greek ' meaning 'lizard') comprise a group of extinct, large marine reptiles from the Late Cretaceous. Their first fossil remains were discovered in a limestone quarry at Maastricht on the ...

between its jaws.

"Unicerosaurus"

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

Glen Rose, Texas Glen Rose is a city in and the county seat of Somervell County, Texas, United States. As of the 2012 census estimate, the city population was 2,502. History 19th century The area was first settled in 1849 by Charles Barnard, who opened a tradi ...

, 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 antiquity as a beast with a single large, pointed, spiraling horn projecting from its forehead. In European literature and art, the unicorn has for the last thousand years o ...

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 (; he, בְּהֵמוֹת, ''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; he is paired with the other chaos-monster, Leviathan, and ...

and

Leviathan Leviathan (; he, לִוְיָתָן, ) is a sea serpent 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, the Book of Amos, and, according to so ...

, 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 Kansas.

Notes

References

External links

BBC

Canadian Fossil Discovery Centre
{{Taxonbar, from=Q131444 Ichthyodectidae 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 Prehistoric fish of Australia Prehistoric 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