''Cylindracanthus'' is an extinct, enigmatic genus of 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 ...

with fossils known throughout North America, Europe, Asia and Africa 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

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 ...

'''', with potential Oligocene records and a possible

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

record also known.'''' It is exclusively known from its distinctive partial remains, which are long cylindrical bony spines that are usually considered

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit ** podium * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ...

fragments, as well as some associated teeth. These spines are abundant & widespread throughout this timespan, and are useful indicators of a nearshore marine environment, but the taxonomic identity of the fish is still highly uncertain and debated.''BARBARA S. GRANDSTAFF, RODRIGO A. PELLEGRINI ,, KENNETH A. MONSCH, DAVID C. PARRIS and DONALD CLEMENT
OVER A CENTURY OF THIN-SECTION MICROSCOPY OF THE FOSSIL FISH CYLINDRACANTHUS
NEW JERSEY STATE MUSEUM INVESTIGATIONS NO. 6, 2018''

Taxonomy

Most of the earlier-described species in this genus were previously classified in ''Coelorhynchus'', a genus which was later found to be preoccupied by the alternative name of an extant

grenadier A grenadier ( , ; derived from the word ''grenade'') was historically an assault-specialist soldier who threw hand grenades in siege operation battles. The distinct combat function of the grenadier was established in the mid-17th century, when ...

fish (now known as ''

Coelorinchus ''Coelorinchus'' is a genus of rattail fish. The name derives from Greek κοῖλος (''koilos'', "hollow") and ῥύγχος (''rhynchos'', "snout"). Species There are currently 121 recognized species in this genus: * '' Coelorinchus acanth ...

''), so they were reclassified into ''Cylindracanthus''.'''' ''Cylindracanthus'' was originally considered a

billfish The billfish are a group (Xiphioidea) of saltwater fish, saltwater predatory fish characterised by prominent pointed beak, bills (rostrum (anatomy), rostra), and by their large size; some are longer than . Extant billfish include sailfish and m ...

, possibly related to ''

Blochius ''Blochius'' is an extinct genus of billfish from the Eocene. It is only known from the Monte Bolca deposits in Italy, and was likely restricted to shallow, tropical waters of the Tethys Ocean. Discovery The existence of ''Blochius'' was known ...

'', due to a presumed similarity in rostral spines, and was thus suggested to be the earliest billfish in the fossil record.'''' However, later studies have found to be the structure of the rostrum to be dissimilar, and it is thus unlikely to be closely related. Later, some later studies suggested closer affinities to the

Acipenseriformes Acipenseriformes is an order (biology), order of basal (phylogenetics), basal Actinopterygii, ray-finned fishes that includes living and fossil sturgeons and paddlefishes (Acipenseroidei), as well as the extinct family (biology), families C ...

, based on the potential for the spines to be the only bony parts of an otherwise cartilaginous ray-finned fish akin to chondrosteans.Parris, D. C., Grandstaff, B. S. and Bell, G. L. 2001. Reassessment of the affinities of the extinct genus ''Cylindracanthus'' (Osteichthyes). ''Proceedings of the South Dakota Academy of Science'', 80: 161–172. However, this was later rejected due to the lack of

osteocytes An osteocyte, an oblate-shaped type of bone cell with dendritic processes, is the most commonly found cell in mature bone. It can live as long as the organism itself. The adult human body has about 42 billion of them. Osteocytes do not divide and ...

in histologically examined specimens, which resembles the condition of derived

teleosts Teleostei (; Greek ''teleios'' "complete" + ''osteon'' "bone"), members of which are known as teleosts (), is, by far, the largest group of ray-finned fishes (class Actinopterygii), with 96% of all extant species of fish. The Teleostei, which i ...

'''' It has been noted that the teeth of Cenozoic ''Cylindracanthus'' are much smaller than the already-small teeth of the Cretaceous ''Cylindracanthus'', suggesting that the teeth may have been a vestigial structure that became gradually reduced over time. It is also uncertain whether the spines are really rostra, or may instead be the ray spines of a fish's fin.

Species

The following species are known, although the validity of many of these is uncertain:'''' * ''C. acus'' (

Cope A cope ( ("rain coat") or ("cape")) is a liturgical long mantle or cloak, open at the front and fastened at the breast with a band or clasp. It may be of any liturgical colour. A cope may be worn by any rank of the Catholic or Anglican clerg ...

, 1870) -

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

(

Bartonian The Bartonian is, in the International Commission on Stratigraphy's (ICS) geologic time scale, a stage or age in the middle of the Eocene Epoch or Series. The Bartonian Age spans the time between . It is preceded by the Lutetian and is follow ...

) 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 ...

(

Gosport Formation Gosport ( ) is a town and non-metropolitan district with borough status in Hampshire, England. At the 2021 Census, the town had a population of 70,131 and the district had a population of 81,952. Gosport is situated on a peninsula on the west ...

) 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 ...

(

Shark River Formation The Shark River Formation is a geologic formation in Texas. It preserves fossils dating back to the Paleogene period. See also * List of fossiliferous stratigraphic units in Texas * Paleontology in Texas Paleontology in Texas refers to paleo ...

), USA * ''C. bisulcatus''

Arambourg Camille Arambourg (February 3, 1885 – November 19, 1969) was a French vertebrate paleontologist. He conducted extensive field work in North Africa. In the 1950s, he argued against the prevailing model of Neanderthals as brutish and simian. Du ...

& Jolead, 1943 - Late Cretaceous (

Coniacian The Coniacian is an age or stage in the geologic timescale. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series and spans the time between 89.8 ± 1 Ma and 86.3 ± 0.7 Ma (million years ago). The Coniacian is preceded by ...

Santonian The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya ( million years ago) and 83.6 ± 0.7 m ...

) of

Niger Niger, officially the Republic of the Niger, is a landlocked country in West Africa. It is a unitary state Geography of Niger#Political geography, bordered by Libya to the Libya–Niger border, north-east, Chad to the Chad–Niger border, east ...

* ''C. cretaceus'' Egerton ''ex'' Dixon, 1850 - Late Cretaceous of England,

Cenomanian The Cenomanian is, in the International Commission on Stratigraphy's (ICS) geological timescale, the oldest or earliest age (geology), age of the Late Cretaceous epoch (geology), Epoch or the lowest stage (stratigraphy), stage of the Upper Cretace ...

of France, Maastrichtian of Germany & Belgium, possibly

Turonian The Turonian is, in the International Commission on Stratigraphy, ICS' geologic timescale, the second age (geology), age in the Late Cretaceous epoch (geology), Epoch, or a stage (stratigraphy), stage in the Upper Cretaceous series (stratigraphy), ...

of the

Democratic Republic of the Congo The Democratic Republic of the Congo (DRC), also known as the DR Congo, Congo-Kinshasa, or simply the Congo (the last ambiguously also referring to the neighbouring Republic of the Congo), is a country in Central Africa. By land area, it is t ...

and middle Eocene of Germany * ''C. gigas'' ( Woodward, 1888) - Middle Eocene (

Lutetian The Lutetian is, in the geologic timescale, a stage (stratigraphy), stage or age (geology), age in the Eocene. It spans the time between . The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it ...

) of

Egypt Egypt ( , ), officially the Arab Republic of Egypt, is a country spanning the Northeast Africa, northeast corner of Africa and Western Asia, southwest corner of Asia via the Sinai Peninsula. It is bordered by the Mediterranean Sea to northe ...

, and possibly

Nigeria Nigeria, officially the Federal Republic of Nigeria, is a country in West Africa. It is situated between the Sahel to the north and the Gulf of Guinea in the Atlantic Ocean to the south. It covers an area of . With Demographics of Nigeria, ...

and the Democratic Republic of the Congo.'''' The

type specimen In biology, a type is a particular wikt:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to ancho ...

was found within the rock of the

Great Sphinx The Great Sphinx of Giza is a limestone statue of a reclining sphinx, a mythical creature with the head of a human and the body of a lion. Facing east, it stands on the Giza Plateau on the west bank of the Nile in Giza, Egypt. The original sh ...

. * ''C. isnusris'' Udovichenko & Nessov, 1987 - Eocene of

Uzbekistan , image_flag = Flag of Uzbekistan.svg , image_coat = Emblem of Uzbekistan.svg , symbol_type = Emblem of Uzbekistan, Emblem , national_anthem = "State Anthem of Uzbekistan, State Anthem of the Republ ...

* ''C. landanensis'' Darteville & Casier, 1949 - middle Eocene of the Democratic Republic of the Congo (possibly a subspecies of ''rectus'') * ''C. libanicus'' (Woodward, 1942) - Cenomanian of

Lebanon Lebanon, officially the Republic of Lebanon, is a country in the Levant region of West Asia. Situated at the crossroads of the Mediterranean Basin and the Arabian Peninsula, it is bordered by Syria to the north and east, Israel to the south ...

(

Sannine Formation The Sannine Formation, also called the Sannine Limestone, is a Cretaceous geologic formation in Lebanon. It is a Konservat-Lagerstätte that contains a high diversity of well-preserved fish, reptiles, and invertebrates from the Tethys Ocean wit ...

) * ''C. octocostatus'' Casier, 1946 -

of Belgium * ''C. ornatus'' Leidy, 1856 - Late Cretaceous (

Campanian The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campa ...

) of New Jersey ( Mount Laurel Formation) &

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 ...

(

Tar Heel Formation The Tar Heel Formation, also known as the Coachman Formation in South Carolina, is a Late Cretaceous (early to middle Campanian-aged) geologic formation in North Carolina and South Carolina, USA. It preserves fossils, including amber dating back t ...

), USA,

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 ...

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 Arkansas ( Arkdelphia Marl), USA, and

Early Eocene In the geologic timescale the Ypresian is the oldest age (geology), age or lowest stage (stratigraphy), stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by th ...

Early Oligocene The Rupelian is, in the geologic timescale, the older of two age (geology), ages or the lower of two stage (stratigraphy), stages of the Oligocene epoch (geology), Epoch/series (stratigraphy), Series. It spans the time between . It is preceded b ...

, USA ( Tallahatta Formation & Red Bluff Clay) (possibly synonymous with ''C. rectus'') * ''C. rectus'' (

Agassiz Jean Louis Rodolphe Agassiz ( ; ) FRS (For) FRSE (May 28, 1807 – December 14, 1873) was a Swiss-born American biologist and geologist who is recognized as a scholar of Earth's natural history. Spending his early life in Switzerland, he recei ...

, 1843) - Early Eocene to Late Eocene (possibly Early Oligocene) of Belgium, England, Germany, France, Italy,

Romania Romania is a country located at the crossroads of Central Europe, Central, Eastern Europe, Eastern and Southeast Europe. It borders Ukraine to the north and east, Hungary to the west, Serbia to the southwest, Bulgaria to the south, Moldova to ...

Syria Syria, officially the Syrian Arab Republic, is a country in West Asia located in the Eastern Mediterranean and the Levant. It borders the Mediterranean Sea to the west, Turkey to Syria–Turkey border, the north, Iraq to Iraq–Syria border, t ...

Namibia Namibia, officially the Republic of Namibia, is a country on the west coast of Southern Africa. Its borders include the Atlantic Ocean to the west, Angola and Zambia to the north, Botswana to the east and South Africa to the south; in the no ...

, Morocco,

Algeria Algeria, officially the People's Democratic Republic of Algeria, is a country in the Maghreb region of North Africa. It is bordered to Algeria–Tunisia border, the northeast by Tunisia; to Algeria–Libya border, the east by Libya; to Alger ...

Angola Angola, officially the Republic of Angola, is a country on the west-Central Africa, central coast of Southern Africa. It is the second-largest Portuguese-speaking world, Portuguese-speaking (Lusophone) country in both total area and List of c ...

, the Democratic Republic of the Congo, Nigeria,

Barbados Barbados, officially the Republic of Barbados, is an island country in the Atlantic Ocean. It is part of the Lesser Antilles of the West Indies and the easternmost island of the Caribbean region. It lies on the boundary of the South American ...

, and the United States (Alabama, Georgia, Louisiana, Maryland, Mississippi, New Jersey, North Carolina, Texas, Virginia) (=''C. burtini'' le Hon, 1871) * ''C. senegalensis'' Leriche, 1936 - Middle Eocene of

Senegal Senegal, officially the Republic of Senegal, is the westernmost country in West Africa, situated on the Atlantic Ocean coastline. It borders Mauritania to Mauritania–Senegal border, the north, Mali to Mali–Senegal border, the east, Guinea t ...

* ''C. sinuatus'' (Agassiz, 1844) - Early Eocene of England (''nomen nudum'') * ''C. sulcatus'' (von Schafhäutl, 1863) - Middle Eocene of Germany Some sources consider only three species to be valid: ''C. acus'' (spines more ossified and smaller tooth remains than ''C. ornatus''), ''C. ornatus'', and ''C. rectus'' (no bilateral symmetry in spines, unlike ''C. ornatus''). However, some sources also synonymize ''C. ornatus'' with ''C. rectus''.'''' Indeterminate remains are known from the USA (Delaware, South Carolina, Kansas and South Dakota), Mali, Togo, Ukraine, India and Pakistan.''''

References

External links

Bony fish in the online Sepkoski Database

''Cylindracanthus''
at fossilworks
3D skull model of ''C. rectus''
at

Sketchfab Sketchfab is a 3D asset website used to publish, share, discover, buy and sell 3D model, 3D, Virtual reality, VR and Augmented reality, AR content. It provides a viewer based on the WebGL and WebXR technologies that allows users to display 3D m ...

{{Taxonbar, from=Q5199273 Prehistoric ray-finned fish genera Enigmatic ray-finned fish taxa Late Cretaceous bony fish Paleocene fish Eocene fish Eocene fish of Asia Cretaceous fish of Europe Eocene fish of Europe Late Cretaceous fish of North America Paleogene fish of North America Late Cretaceous fish of Africa Eocene fish of Africa Cenomanian genus first appearances Turonian genera Coniacian genera Santonian genera Campanian genera Maastrichtian genera Danian genera Ypresian genera Lutetian genera Bartonian genera Priabonian genus extinctions Fossils of the United States Fossils of Barbados Fossils of Namibia Fossils of Angola Fossils of the Democratic Republic of the Congo Fossils of Nigeria Fossils of Niger Fossils of Senegal Fossils of Togo Fossils of Mali Fossils of Algeria Fossils of Morocco Fossils of Egypt Fossils of Syria Fossils of Lebanon Fossils of Pakistan Fossils of India Fossils of Uzbekistan Fossils of Ukraine Fossils of Romania Fossils of Italy Fossils of Germany Fossils of Belgium Fossils of France Fossils of England Taxa named by Joseph Leidy Fossil taxa described in 1856