''Ctenospondylus'' ("comb vertebra") is an extinct genus of

sphenacodontid Sphenacodontidae (Greek: "wedge point tooth family") is an extinct family of small to large, advanced, carnivorous, Late Pennsylvanian to middle Permian pelycosaurs. The most recent one, ''Dimetrodon angelensis'', is from the late Kungurian or ...

synapsid Synapsids + (, 'arch') > () "having a fused arch"; synonymous with ''theropsids'' (Greek, "beast-face") are one of the two major groups of animals that evolved from basal amniotes, the other being the sauropsids, the group that includes rep ...

Species were about three meters (ten feet) long. The genus is known only from the 'Seymouran' Land Vertebrate Faunachron, which is equivalent to the upper part of the

Artinskian In the geologic timescale, the Artinskian is an age or stage of the Permian. It is a subdivision of the Cisuralian Epoch or Series. The Artinskian likely lasted between and million years ago (Ma) according to the most recent revision of th ...

stage Stage or stages may refer to: Acting * Stage (theatre), a space for the performance of theatrical productions * Theatre, a branch of the performing arts, often referred to as "the stage" * ''The Stage'', a weekly British theatre newspaper * Sta ...

and the lowermost

Kungurian In the geologic timescale, the Kungurian is an age or stage of the Permian. It is the latest or upper of four subdivisions of the Cisuralian Epoch or Series. The Kungurian lasted between and million years ago (Ma). It was preceded by the Art ...

stage of the Early

Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Pale ...

. Its fossils were found in the

U.S. 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 territor ...

states State may refer to: Arts, entertainment, and media Literature * '' State Magazine'', a monthly magazine published by the U.S. Department of State * ''The State'' (newspaper), a daily newspaper in Columbia, South Carolina, United States * ''Our ...

Ohio Ohio () is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Of the List of states and territories of the United States, fifty U.S. states, it is the List of U.S. states and territories by area, 34th-l ...

and

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

. It was a carnivore and preyed upon animals close to its size. ''Ctenospondylus'' had a long

tail The tail is the section at the rear end of certain kinds of animals’ bodies; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals ...

, short back spines, and a very deep yet narrow skull with massive jaws that had sharp teeth. Because of its large size, it was probably the

apex predator An apex predator, also known as a top predator, is a predator at the top of a food chain, without natural predators of its own. Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the highest trophic le ...

in its environment, and might have competed with other predators like ''Dimetrodon'' for food. A

, it was a close relative of ''

Dimetrodon ''Dimetrodon'' ( or ,) meaning "two measures of teeth,” is an extinct genus of non- mammalian synapsid that lived during the Cisuralian (Early Permian), around 295–272 million years ago (Mya). It is a member of the family Sphenacodo ...

''. In 1936,

Alfred Sherwood Romer Alfred Sherwood Romer (December 28, 1894 – November 5, 1973) was an American paleontologist and biologist and a specialist in vertebrate evolution. Biography Alfred Romer was born in White Plains, New York, the son of Harry Houston Romer an ...

named the

type species In 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 species that contains the biological type specimen( ...

''Ctenospondylus casei''. The generic name, from Greek κτείς, ''kteis'', "comb", and σφόνδυλος, ''sphondylos'', "vertebra", referred to the form of the back sail. The specific name honoured

Ermine Cowles Case Ermine Cowles Case (1871–1953), invariably known as E.C. Case, was a prominent American paleontologist in the second generation that succeeded Othniel Charles Marsh and Edward Drinker Cope. A graduate of the University of Kansas, with a Ph ...

, who first reported the type specimen in 1910. The fossil had been found in Archer County at the Slippery Creek site in the

Belle Plains Formation The Belle Plains Formation is a geologic formation in Texas. It preserves fossils dating back to the Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period ...

, dating from the

. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of seve ...

is AMNH 4047, already found in 1881 by

William Fletcher Cummins William is a masculine given name of Norman French origin.Hanks, Hardcastle and Hodges, ''Oxford Dictionary of First Names'', Oxford University Press, 2nd edition, , p. 276. It became very popular in the English language after the Norman conques ...

, collecting for

Edward Drinker Cope Edward Drinker Cope (July 28, 1840 – April 12, 1897) was an American zoologist, paleontologist, comparative anatomist, herpetologist, and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy intereste ...

. It consists of a neck vertebra, two back vertebrae, two broken off spines and rib fragments. In 1964, far more complete material from

Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to its ...

and

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a U.S. state, state in the Southwestern United States. It is the list of U.S. states and territories by area, 6th largest and the list of U.S. states and territories by population, 14 ...

was referred to the species by Peter P. Vaughn. This included specimen NTM VP 1001: a partial skeleton with skull; NTM VP 10014: a number of back vertebrae; NTM VP 10015: additional back vertebrae; NTM VP 10016: two skull bones; and NTM VP 10017: a series of three back vertebrae. The specimens are part of the collection of the ''

Navajo Tribal Museum The Navajo Nation Museum is a museum and library on Navajo ground in Window Rock, Arizona. Its collections, exhibits, and other activities focus on the cultural history of the Navajo people. Its activities include traditional museum exhibits, a ...

''. In 1978, David Berman named a second species: ''Ctenospondylus ninevehensis''. The specific name refers to the

Niniveh Limestone Member Nineveh (; akk, ; Biblical Hebrew: '; ar, نَيْنَوَىٰ '; syr, ܢܝܼܢܘܹܐ, Nīnwē) was an ancient Assyrian city of Upper Mesopotamia, located in the modern-day city of Mosul in northern Iraq. It is located on the eastern ban ...

of the Greene Formation, dating from the

Sakmarian In the geologic timescale, the Sakmarian is an age or stage of the Permian. It is a subdivision of the Cisuralian Epoch or Series. The Sakmarian lasted between 293.52 and million years ago (Ma). It was preceded by the Asselian and followed b ...

where it was found at Clark Hill in Monroe County, Ohio. The holotype is specimen MCZ 3386, found by

Donald Baird Donald is a masculine given name derived from the Gaelic name ''Dòmhnall''.. This comes from the Proto-Celtic *''Dumno-ualos'' ("world-ruler" or "world-wielder"). The final -''d'' in ''Donald'' is partly derived from a misinterpretation of the ...

in June 1955. It consists of a partial skeleton with fragmentary skull, a spine from the axis, four back vertebrae, four tail vertebrae, neck ribs, dorsal ribs, a shoulder blade, two humeri, and the right pelvis. Specimen MCZ 4458, a right maxilla, was referred to the species. Berman considered ''C. ninevehensis'' more basal than ''Ctenospondylus casei'' and only referred the second species to the genus because of the similar spine length. Later specimen MCZ 8635-42 was referred, a skull; MCZ 8665, a

jugal bone The jugal is a skull bone found in most reptiles, amphibians and birds. In mammals, the jugal is often called the malar or zygomatic. It is connected to the quadratojugal and maxilla, as well as other bones, which may vary by species. Anat ...

and MCZ 3102, a skeleton with skull. The spines of ''Ctenospondylus'' are longer than those of ''

Sphenacodon ''Sphenacodon'' (meaning "wedge point tooth") is an extinct genus of synapsid that lived from about 300 to about 280 million years ago (Ma) during the Late Carboniferous and Early Permian periods. Like the closely related ''Dimetrodon'', ''Sphe ...

'' but shorter than those of ''Dimetrodon''. They also lack the dumbbell-shaped upper profile of the latter genus and are more transversely flattened. The skull of ''Ctenospondylus'' is, as far as can be judged from the limited material found, very similar to that of other sphenacodontids.Eberth, D.A. 1985. "The skull of ''Sphenacodon ferocior'', and comparisons with other sphenacodontines (Reptilia: Pelycosauria)". ''New Mexico Bureau of Mines and Mineral Resources Circular'' 190: 5–39

Gallery

image:CtenospondylusDB.jpg image:Ctenospondylus2DB2.jpg

References

{{Taxonbar, from=Q609565 Sphenacodontidae Cisuralian synapsids of North America Prehistoric synapsid genera Guadalupian synapsids Taxa named by Alfred Romer Fossil taxa described in 1936 Artinskian genus first appearances Kungurian genus extinctions

Gallery

See also

References