Monoclonius

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Monoclonius

Monoclonius (meaning "single stem"; referring to the teeth, which have a single root) was a ceratopsian dinosaur

Dinosaur

Dinosaurs were the dominant vertebrate animals of Landform ecosystems for over 160 million years, from the late Triassic Period until the end of the Cretaceous Period , when most of them became extinct in the Cretaceous?Tertiary extinction event....
from the Judith River Formation

Judith River Formation

The Judith River Formation is a fossil-bearing geologic formation in Montana, and is part of the Judith River Group. It dates to the upper Cretaceous....
of Late Cretaceous

Late Cretaceous

Late Cretaceous refers to the second half of the Cretaceous Period , named after the famous white chalk cliffs of southern England, which date from this time....
Montana

Montana

Montana is a U.S. state in the Western United States. The western third of the state contains numerous mountain ranges; other 'island' ranges are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains....
and Canada

Canada

Canada is a country occupying most of northern North America, extending from the Atlantic Ocean in the east to the Pacific Ocean in the west and northward into the Arctic Ocean....
. It is often confused with Centrosaurus
Centrosaurus

Centrosaurus is an herbivorous Ceratopsidae dinosaur from the late Cretaceous of North America, approximately 75 million years ago.The name refers to the series of small hornlets placed along the margin of the frill, and not to the horn on its nose ....
, a similar genus of ceratopsian (some think the two may even be identical, of a different age or gender). Monoclonius was described by Edward Drinker Cope

Edward Drinker Cope

Edward Drinker Cope was an United States paleontology and comparative anatomy, as well as a noted herpetology and ichthyology.Born to a wealthy Society of Friends family, Cope quickly distinguished himself as a child prodigy interested in science; he published his first scientific paper in 1859....
in 1876.

Monoclonius was Edward Drinker Cope
Edward Drinker Cope

Edward Drinker Cope was an United States paleontology and comparative anatomy, as well as a noted herpetology and ichthyology.Born to a wealthy Society of Friends family, Cope quickly distinguished himself as a child prodigy interested in science; he published his first scientific paper in 1859....
's third named ceratopsian (after Agathaumas

Agathaumas

Polyonax

Polyonax was a genus of ceratopsid dinosaur from the Maastrichtian-age Upper Cretaceous Denver Formation of Colorado, USA. Founded upon poor remains, it is today regarded as a nomen dubium....
) and the only one of the three that has any validity.

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Encyclopedia

Monoclonius (meaning "single stem"; referring to the teeth, which have a single root) was a ceratopsian dinosaur
Dinosaur

Dinosaurs were the dominant vertebrate animals of Landform ecosystems for over 160 million years, from the late Triassic Period until the end of the Cretaceous Period , when most of them became extinct in the Cretaceous?Tertiary extinction event....
from the Judith River Formation
Judith River Formation

The Judith River Formation is a fossil-bearing geologic formation in Montana, and is part of the Judith River Group. It dates to the upper Cretaceous....
of Late Cretaceous
Late Cretaceous

Late Cretaceous refers to the second half of the Cretaceous Period , named after the famous white chalk cliffs of southern England, which date from this time....
Montana
Montana

Montana is a U.S. state in the Western United States. The western third of the state contains numerous mountain ranges; other 'island' ranges are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains....
and Canada
Canada

Canada is a country occupying most of northern North America, extending from the Atlantic Ocean in the east to the Pacific Ocean in the west and northward into the Arctic Ocean....
. It is often confused with Centrosaurus
Centrosaurus

Centrosaurus is an herbivorous Ceratopsidae dinosaur from the late Cretaceous of North America, approximately 75 million years ago.The name refers to the series of small hornlets placed along the margin of the frill, and not to the horn on its nose ....
, a similar genus of ceratopsian (some think the two may even be identical, of a different age or gender). Monoclonius was described by Edward Drinker Cope
Edward Drinker Cope

Edward Drinker Cope was an United States paleontology and comparative anatomy, as well as a noted herpetology and ichthyology.Born to a wealthy Society of Friends family, Cope quickly distinguished himself as a child prodigy interested in science; he published his first scientific paper in 1859....
in 1876.

History
Monoclonius was Edward Drinker Cope
Edward Drinker Cope

Edward Drinker Cope was an United States paleontology and comparative anatomy, as well as a noted herpetology and ichthyology.Born to a wealthy Society of Friends family, Cope quickly distinguished himself as a child prodigy interested in science; he published his first scientific paper in 1859....
's third named ceratopsian (after Agathaumas

Agathaumas

Polyonax

Polyonax was a genus of ceratopsid dinosaur from the Maastrichtian-age Upper Cretaceous Denver Formation of Colorado, USA. Founded upon poor remains, it is today regarded as a nomen dubium....
) and the only one of the three that has any validity. The type specimen was found in the summer of 1876 in Montana, only about 100 miles from the site of the Battle of the Little Bighorn
Battle of the Little Bighorn

The Battle of the Little Bighorn—also known as Custer's Last Stand, and, in the parlance of the relevant Native Americans in the United States, the Battle of Greasy Grass Creek—was an armed engagement between a Lakota people-Northern Cheyenne combined force and the U.S....
that June. Although it was not an articulated skeleton, Cope recovered most of the animal (only the feet were entirely missing), including skull material and the base part of a long nasal horn. Since the ceratopsians were still unknown, Cope was uncertain about much of the skull material, not recognizing the horn core as part of a fossil horn.

After O. C. Marsh's description of Triceratops

Triceratops

Triceratops is an extinct genus of herbivore Ceratopsidae dinosaur which lived during the Maastrichtian stage of the Late Cretaceous Period , around 68 to 65 mya in what is now North America....
in 1889, Cope reexamined his Monoclonius specimen and realized that Triceratops, Monoclonius, and Agathaumas

Agathaumas

Agathaumas is a name given to the remains of a large ceratopsid that lived in Wyoming during the Late Cretaceous . The name comes from Ancient Greek, a?a? - 'much' and ?a??a - 'wonder'....
represented a group of similar dinosaurs. In the same paper that Cope examined M. crassus, he also named three more Monoclonius species. He described Monoclonius as having a large nasal horn and two smaller horns over the eyes and a large frill
Frill

Frill may refer to:* Frill , a form of trimming* Neck frill, the relatively extensive margin seen on the back of the heads of some reptiles* Oriental Frill, a breed of Fancy pigeon...
(parietal
Parietal

Parietal may refer to:*Parietal lobe of the brain*Parietal bone of the skull*Parietal scales of a snake lie in the general region of the parietal bone....
) with broad openings.

Later, John Bell Hatcher
John Bell Hatcher

John Bell Hatcher was an USA paleontologist and fossil hunter best known for discovering Torosaurus.Born in Cooperstown, Illinois, Illinois, his farmer father moved the family when Hatcher was young to Cooper, Iowa, where he received his early education....
(one of Marsh's workers and therefore in the 'Yale
YALE

RapidMiner is an environment for machine learning and data mining experiments. It allows experiments to be made up of a large number of arbitrarily nestable operators, described in XML files which can easily be created with RapidMiner's graphical user interface....
Camp' of the Bone Wars
Bone Wars

The Bone Wars, also known as the "Great Dinosaur Rush", refers to a period of intense fossil speculation and discovery during the Gilded Age of American history, marked by a heated rivalry between Edward Drinker Cope and Othniel Charles Marsh ....
), in continuing Marsh's monograph on the Ceratopsidae
Ceratopsidae

Ceratopsidae is a speciose group of marginocephalian dinosaurs including Triceratops and Styracosaurus. All known species were quadrupedal herbivores from the Upper Cretaceous of Western North America and are characterized by beaks, rows of shearing teeth in the back of the jaw, and elaborate horns and frills....
, derided Cope's collecting methods. Cope rarely identified specimens in the field with precise locations and often ended up describing composite
Composite

Composite may refer to:Acting, Film, and Studio* Composite card, a marketing tool for actors and especially models* Composite character, a character in an adaptation of a work formed from two or more characters from the original work...
s, rather than single individuals. Hatcher reexamined the type specimen of M. crassus and the only skull remain that he could positively assign to this specimen was the left half of the parietal (the dorsal part of the neck frill). He could not assign any of the several squamosal
Squamosal

The squamosal is a bone of the head of higher vertebrates. It is the principal component of the cheek region in the skull, lying below the temporal series and otic notch and bounded anteriorly by postorbital....
s (side of the frill) in the collection to the type specimen and did not believe that Cope's orbital horn (catalogued under a different number) belonged to it.

Centrosaurus intrudes

In the years after Cope's 1889 paper, it appears that there was a tendency to describe everything from the Judith River beds as Monoclonius. The first dinosaur species described from Canada were ceratopsians in 1902 by Lawrence Lambe
Lawrence Lambe

Lawrence Morris Lambe was a Geology and Palaeontology from the Geological Survey of Canada . He was Canada's first great geologist. His published work, describing the diverse and plentiful dinosaur discoveries from the fossil beds in Alberta, did much to bring dinosaurs into the public eye and helped usher in the Golden Age of Dinosaurs...
, including three new species of Monoclonius based on fragmentary skulls. In 1904, Lambe described Centrosaurus

Centrosaurus

Brachyceratops

Brachyceratops ) is a genus of ceratopsian dinosaur. It lived during the Late Cretaceous Period . Its fossils have been found in Alberta, Canada and Montana, United States....
and M. sphenocerus to Styracosaurus

Styracosaurus

Styracosaurus was a genus of herbivore ceratopsian dinosaur from the Cretaceous Period , about 76.5 to 75.0 million years ago. It had four to six long horns extending from its neck frill, a smaller horn on each of its cheeks, and a single horn protruding from its nose, which may have reached dimensions of around 60 centimeters lon...
. This left M. crassus, which he considered non-diagnostic, largely due to its damage and the lack of a nasal horn. Lambe ended the paper by attributing Brown's M. flexus to Centrosaurus apertus (the type species of Centrosaurus). The next round fell to Brown in a paper on Albertan centrosaurines, which, for the first time, analyzed a complete ceratopsian skeleton, which he named Monoclonius nasicornis (he contributed to the confusion even more by describing yet another species, M. cutleri).

The matter bounced back and forth, over the next few years, until Richard Swann Lull
R. S. Lull

Richard Swann Lull was an United States paleontologist from the early 20th century, active at Yale University, who is largely remembered now for championing a Pre-Neo-Darwinian Synthesis view of evolution, whereby mutation could unlock mysterious genetic drives that, over time, would lead populations to increasingly extreme phenotypes ....
published his "Revision of Ceratopsia", in 1933. Although, unlike the beautifully illustrated 1907 monograph, it has relatively few illustrations, it is known for the attempt to identify and locate all ceratopsian specimens then known. Lull described another specimen from Alberta (YPM 2015; Monoclonius (Centrosaurus) flexus) and decided that Centrosaurus

Centrosaurus

Centrosaurus is an herbivorous Ceratopsidae dinosaur from the late Cretaceous of North America, approximately 75 million years ago.The name refers to the series of small hornlets placed along the margin of the frill, and not to the horn on its nose ....
was a junior synonym of Monoclonius, perhaps distinct enough to deserve subgeneric rank. (This specimen is exhibited at Yale's Peabody Museum in an unusual way: the left half shows the skeleton, but the right side is a reconstruction of the living animal.) Charles M. Sternberg, son of Charles H. Sternberg, in 1940 firmly established the existence of Monoclonius-type forms in Alberta (no further specimens have come from Montana since 1876) and showed that differences justified the separation of the two genera. Monoclonius-types are rarer and found in earlier horizons than Centrosaurus-types, seemingly indicating that the one is probably ancestral to the other.

Classification
Monoclonius belonged to the Centrosaurinae subfamily within the Ceratopsia
Ceratopsia

Ceratopsia or Ceratopia is a group of herbivore, beaked dinosaurs which thrived in what are now North America and Asia, during the Cretaceous Period , although ancestral forms lived earlier, in the Jurassic....
(the name is Greek
Ancient Greek

Ancient Greek is the historical stage in the development of the Greek language spanning across the Archaic Greece , Classical Greece , and Hellenistic civilization periods of ancient Greece and the classical antiquity....
for "horned face"), a group of herbivorous dinosaurs with parrot
Parrot

File:Ara ararauna -eating -Wilhelma Zoo-8-2rc.jpgParrots, also known as psittacines , are birds of the roughly 372 species in 86 genus that make up the order Psittaciformes, found in most warm and tropical regions....
-like beaks which thrived in North America
North America

North America is the northern continent of the Americas, situated in the Earth's northern hemisphere and almost totally in the western hemisphere....
and Asia
Asia

Asia is the world's largest and most populous continent. It covers 8.6% of the Earth's total surface area and, with over 4 billion people, it contains more than 60% of the world's current human population....
during the Cretaceous Period. The Cretaceous ended roughly 65 million years ago, by which time all known Ceratopsians had become extinct.

Species
Type:

Monoclonius crassus Cope 1876 [AMNH 3998]

Other Species:

M. albertensis (Lambe, 1913/Leahy, 1987); included with Styracosaurus
Styracosaurus

Styracosaurus was a genus of herbivore ceratopsian dinosaur from the Cretaceous Period , about 76.5 to 75.0 million years ago. It had four to six long horns extending from its neck frill, a smaller horn on each of its cheeks, and a single horn protruding from its nose, which may have reached dimensions of around 60 centimeters lon...
albertensis.
M. apertus (Lambe, 1904/Kuhn, 1964); included with Centrosaurus
Centrosaurus

Centrosaurus is an herbivorous Ceratopsidae dinosaur from the late Cretaceous of North America, approximately 75 million years ago.The name refers to the series of small hornlets placed along the margin of the frill, and not to the horn on its nose ....
apertus.
M. belli (Lambe, 1902); included with Chasmosaurus
Chasmosaurus

Chasmosaurus is a genus of Ceratopsidae dinosaur from the Upper Cretaceous Period of North America. Its name means 'opening lizard', referring to the large openings in its frill ....
belli.
M. canadensis (Lambe, 1902); included with Chasmosaurus
Chasmosaurus

Chasmosaurus is a genus of Ceratopsidae dinosaur from the Upper Cretaceous Period of North America. Its name means 'opening lizard', referring to the large openings in its frill ....
canadensis.
M. cutleri (Brown, 1917); back half of skeleton with some skull fragments, included with Centrosaurus
Centrosaurus

Centrosaurus is an herbivorous Ceratopsidae dinosaur from the late Cretaceous of North America, approximately 75 million years ago.The name refers to the series of small hornlets placed along the margin of the frill, and not to the horn on its nose ....
apertus.
M. dawsoni (Lambe, 1902; including Brachyceratops
Brachyceratops

Brachyceratops ) is a genus of ceratopsian dinosaur. It lived during the Late Cretaceous Period . Its fossils have been found in Alberta, Canada and Montana, United States....
dawsoni and Centrosaurus
Centrosaurus

Centrosaurus is an herbivorous Ceratopsidae dinosaur from the late Cretaceous of North America, approximately 75 million years ago.The name refers to the series of small hornlets placed along the margin of the frill, and not to the horn on its nose ....
dawsoni), included with Centrosaurus
Centrosaurus

Centrosaurus is an herbivorous Ceratopsidae dinosaur from the late Cretaceous of North America, approximately 75 million years ago.The name refers to the series of small hornlets placed along the margin of the frill, and not to the horn on its nose ....
apertus.
M. fissus Cope, 1889; isolated pterygoid
Pterygoid

Pterygoid can refer to:* Pterygoid processes of the sphenoid bone** The Lateral pterygoid plate by it* a muscle such as Lateral pterygoid muscle or Medial pterygoid muscle...
(Cope identified it as a squamosal
Squamosal

The squamosal is a bone of the head of higher vertebrates. It is the principal component of the cheek region in the skull, lying below the temporal series and otic notch and bounded anteriorly by postorbital....
); nomen nudum
Nomen nudum

The phrase nomen nudum is a Latin language term, meaning "naked name". In taxonomy, this is used to indicate a term or phrase which looks like a scientific name, and may well have been intended to become a scientific name, but fails to be one because it was not published with an adequate description , and thus is "bare" or "naked"....
.
M. flexus (Brown, 1914); included with Centrosaurus
Centrosaurus

Centrosaurus is an herbivorous Ceratopsidae dinosaur from the late Cretaceous of North America, approximately 75 million years ago.The name refers to the series of small hornlets placed along the margin of the frill, and not to the horn on its nose ....
apertus.
M. longirostris (Sternberg, 1940/Kuhn, 1964); included with Centrosaurus
Centrosaurus

Centrosaurus is an herbivorous Ceratopsidae dinosaur from the late Cretaceous of North America, approximately 75 million years ago.The name refers to the series of small hornlets placed along the margin of the frill, and not to the horn on its nose ....
apertus.
M. lowei (Sternberg, 1940); a large, somewhat flattened, skull, apparently that of a subadult (sutures are not completely closed). Sternberg pointed out the resemblances of this specimen to Brachyceratops
Brachyceratops

Brachyceratops ) is a genus of ceratopsian dinosaur. It lived during the Late Cretaceous Period . Its fossils have been found in Alberta, Canada and Montana, United States....
. The species was named in honor of Harold D'acre Robinson Lowe from Drumheller, AB. Lowe was a field assistant to C.M. Sternberg and worked six field seasons (during the 1925-1937 period) with him across southern Alberta, with other work in Manitoba
Manitoba

Manitoba is a prairie provinces in Canada, which has an area of 647,797 square kilometres and a population of 1,207,959 , with more than half located within the Winnipeg Capital Region ....
and Saskatchewan
Saskatchewan

Saskatchewan is a prairie provinces in Canada, which has an area of 588,276.09 square kilometres and a population of 1,015,895 , mostly living in the southern half of the province....
.
M. montanensis (Gilmore, 1914); included with Brachyceratops montanensis.
M. nasicornis (Brown, 1917); included part with Centrosaurus
Centrosaurus

Centrosaurus is an herbivorous Ceratopsidae dinosaur from the late Cretaceous of North America, approximately 75 million years ago.The name refers to the series of small hornlets placed along the margin of the frill, and not to the horn on its nose ....
apertus and part with Styracosaurus
Styracosaurus

Styracosaurus was a genus of herbivore ceratopsian dinosaur from the Cretaceous Period , about 76.5 to 75.0 million years ago. It had four to six long horns extending from its neck frill, a smaller horn on each of its cheeks, and a single horn protruding from its nose, which may have reached dimensions of around 60 centimeters lon...
albertensis (Dodson believes this is actually the female of Styracosaurus)
M. recurvicornis Cope, 1889; braincase, 3 horns and isolated fragments; nomen nudum included with Ceratops
Ceratops

Ceratops was a ceratopsian dinosaur which lived during the Late Cretaceous. Its fossils have been found in Montana and Alberta, Canada. Although poorly known, Ceratops is important in the history of dinosaurs, since it is the type species upon which both Ceratopsia and Ceratopsidae are based....
recurvicornis.
M. sphenoceras Cope, 1890; nasal horn and premaxilla
Premaxilla

The incisive bone is the portion of the maxilla adjacent to the incisors.The term premaxilla can also be used to refer to the incisive bone....
; nomen nudum including Agathaumas
Agathaumas

Agathaumas is a name given to the remains of a large ceratopsid that lived in Wyoming during the Late Cretaceous . The name comes from Ancient Greek, a?a? - 'much' and ?a??a - 'wonder'....
sphenoceras, A. monoclonius and Styracosaurus sphenoceras).

Diet and ecology
Monoclonius, like all Ceratopsians, was a herbivore

Herbivore

Herbivory is a form of predation in which an organism, known as an herbivore, heterotrophs principally autotrophs such as plants, algae and photosynthesizing bacteria....
. During the Cretaceous, flowering plants were "geographically limited on the landscape", so it is likely that this dinosaur fed on the predominant plants of the era: fern

Fern

A fern is any one of a group of about 20,000 species of plants classified in the phylum or division Pteridophyta, also known as Filicophyta....
s, cycad

Cycad

File:Cycad cone.jpgCycads are a group of seed plants characterized by a large crown of compound Leaf and a stout trunk . They are evergreen, gymnospermous, dioecious plants having large pinnately compound leaves....
s and conifers. It would have used its sharp Ceratopsian beak to bite off the leaves or needles.

Monoclonius

History

Centrosaurus intrudes

Classification

Species

Diet and ecology

Footnotes

External links

Offline References