''Titanoceratops'' (meaning "titanic horned face") is a controversial

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

herbivorous A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat n ...

ceratopsia Ceratopsia or Ceratopia ( or ; Ancient Greek, Greek: "horned faces") is a group of herbivore, herbivorous, beaked dinosaurs that thrived in what are now North America, Asia and Europe, during the Cretaceous Period (geology), Period, although ance ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

. It was a giant

chasmosaurine Chasmosaurinae is a subfamily of ceratopsid dinosaurs. They were one of the most successful groups of herbivores of their time. Chasmosaurines appeared in the early Campanian, and became extinct, along with all other non- avian dinosaurs, during ...

ceratopsian Ceratopsia or Ceratopia ( or ; Greek: "horned faces") is a group of herbivorous, beaked dinosaurs that thrived in what are now North America, Asia and Europe, during the Cretaceous Period, although ancestral forms lived earlier, in the Late Ju ...

that lived in 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 ...

period (

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 ...

stage, about 75 million years agoFowler, D. W. 2017. Revised geochronology, correlation, and dinosaur stratigraphic ranges of the Santonian-Maastrichtian (Late Cretaceous) formations of the Western Interior of North America. PLoS ONE 12(11): e0188426.) in what is now

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

. ''Titanoceratops'' was named for its large size, being one of the largest known horned dinosaurs and the type species was named ''T. ouranos'', after

Uranus Uranus is the seventh planet from the Sun. It is a gaseous cyan-coloured ice giant. Most of the planet is made of water, ammonia, and methane in a Supercritical fluid, supercritical phase of matter, which astronomy calls "ice" or Volatile ( ...

(Ouranos), the father of the

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 ...

titan Titan most often refers to: * Titan (moon), the largest moon of Saturn * Titans, a race of deities in Greek mythology Titan or Titans may also refer to: Arts and entertainment Fictional entities Fictional locations * Titan in fiction, fictiona ...

s. It was named in 2011 by

Nicholas R. Longrich Nicholas is a male name, the Anglophone version of an ancient Greek name in use since antiquity, and cognate with the modern Greek , . It originally derived from a combination of two Greek words meaning 'victory' and 'people'. In turn, the name ...

for a specimen previously referred to ''

Pentaceratops ''Pentaceratops'' ("five-horned face") is a genus of herbivorous ceratopsid dinosaur from the late Cretaceous Period of what is now North America. Fossils of this animal were first discovered in 1921, but the genus was named in 1923 when its ty ...

''. Longrich believed that unique features found in the skull reveal it to have been a close relative of ''

Triceratops ''Triceratops'' ( ; ) is a genus of Chasmosaurinae, chasmosaurine Ceratopsia, ceratopsian dinosaur that lived during the late Maastrichtian age of the Late Cretaceous Period (geology), period, about 68 to 66 million years ago on the island ...

'', classified within the subgroup Triceratopsini. However, other researchers have expressed skepticism, and believe "''Titanoceratops''" to simply be an unusually large, old specimen of ''Pentaceratops''. The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

specimen is OMNH 10165, a partial

skeleton A skeleton is the structural frame that supports the body of most animals. There are several types of skeletons, including the exoskeleton, which is a rigid outer shell that holds up an organism's shape; the endoskeleton, a rigid internal fra ...

including a mostly complete

skull The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent ...

and

jaw The jaws are a pair of opposable articulated structures at the entrance of the mouth, typically used for grasping and manipulating food. The term ''jaws'' is also broadly applied to the whole of the structures constituting the vault of the mouth ...

s, and much of the skeleton. It was found in either the upper

Fruitland Formation The Fruitland Formation is a geologic formation found in the San Juan Basin in the states of New Mexico and Colorado, in the United States of America. It contains fossils dating it to the Campanian age of the late Cretaceous.

or the lower

Kirtland Formation The Kirtland Formation (originally the Kirtland Shale) is a Sedimentary rock, sedimentary geological formation. Description The Kirtland Formation is the product of alluvial muds and overbank sand deposits from the many channels draining the ...

. The original quarry is lost, so it is not known which formation the fossil was excavated from. The formations are both late Campanian in age. The skull is incomplete, but as currently reconstructed it measures long, making it a candidate for the longest skull of any land animal. With an estimated weight of and length of , ''Titanoceratops'' was comparable in size with the largest ceratopsians, ''

Torosaurus ''Torosaurus'' (meaning "perforated lizard", in reference to the large openings in its frill) is a genus of herbivorous Chasmosaurinae, chasmosaurine Ceratopsia, ceratopsian dinosaur that lived during the late Maastrichtian age of the Late Cret ...

'' and ''

'', and was likely the largest animal in its ecosystem, if not in North America, at the time.

Description

The skull measures from the tip of the snout to the quadrate, and the restored frill extends its length up to making it a candidate for the longest skull of any land animal. ''Titanoceratops'' was as large as the later triceratopsins ''Triceratops'' and ''Torosaurus'', with an estimated weight of and a mounted skeleton measuring long and tall at the back. In 2016

Gregory S. Paul Gregory Scott Paul (born December 24, 1954) is an American freelance researcher, author and illustrator who works in paleontology. He is best known for his work and research on theropoda, theropod dinosaurs and his detailed illustrations, both l ...

gave a lower estimation of 6.5 meters (21.3 ft) and 4.5 tonnes (4.9 short tons). Tom Holtz (2012) noted that it is extremely similar to its closely related contemporaries ''

Eotriceratops ''Eotriceratops'' (meaning "dawn three-horned face") is a genus of herbivorous ceratopsian dinosaurs which lived in the area of North America during the late Cretaceous period. The only named species is ''Eotriceratops xerinsularis''. Discovery ...

'' and ''

Ojoceratops ''Ojoceratops'' ( meaning "Ojo Alamo horned face") is a genus of ceratopsian dinosaur which lived in what is now New Mexico, United States. ''Ojoceratops'' fossils have been recovered from strata of the Ojo Alamo Formation (Naashoibito Member), d ...

'', which may all be synonymous. The holotype skeleton of ''Titanoceratops'' consists of a partial

with

s, syncervical, cervical, dorsal, and sacral vertebrae, caudal vertebrae,

rib In vertebrate anatomy, ribs () are the long curved bones which form the rib cage, part of the axial skeleton. In most tetrapods, ribs surround the thoracic cavity, enabling the lungs to expand and thus facilitate breathing by expanding the ...

humeri The humerus (; : humeri) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of ...

, a right

radius In classical geometry, a radius (: radii or radiuses) of a circle or sphere is any of the line segments from its Centre (geometry), center to its perimeter, and in more modern usage, it is also their length. The radius of a regular polygon is th ...

femora The femur (; : femurs or femora ), or thigh bone is the only bone in the thigh — the region of the lower limb between the hip and the knee. In many four-legged animals the femur is the upper bone of the hindleg. The top of the femur fits in ...

tibia The tibia (; : tibiae or tibias), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two Leg bones, bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outsi ...

e, a right

fibula The fibula (: fibulae or fibulas) or calf bone is a leg bone on the lateral side of the tibia, to which it is connected above and below. It is the smaller of the two bones and, in proportion to its length, the most slender of all the long bones. ...

, both ilia, both

ischia Ischia ( , , ) is a volcanic island in the Tyrrhenian Sea. It lies at the northern end of the Gulf of Naples, about from the city of Naples. It is the largest of the Phlegrean Islands. Although inhabited since the Bronze Age, as a Ancient G ...

, and ossified tendons. In total, the amount of material assigned to ''Titanoceratops'' means it is quite well known, along with genera like ''

'', ''

Vagaceratops ''Vagaceratops'' (meaning "wandering (''vagus'', Latin) horned face", in reference to its close relationship with ''Kosmoceratops'' from Utah) is a genus of herbivorous ceratopsian dinosaur. It is a chasmosaurine ceratopsian which lived during ...

'', ''

Chasmosaurus ''Chasmosaurus'' ( ) is a genus of ceratopsid dinosaur from the Late Cretaceous Period in North America. Its given name means 'opening lizard', referring to the large openings ( fenestrae) in its frill (Greek ''chasma'', meaning 'opening', 'hol ...

'', ''

Centrosaurus ''Centrosaurus'' ( ; ) is a genus of centrosaurine ceratopsian dinosaur from Campanian age of Late Cretaceous Canada. Their remains have been found in the Dinosaur Park Formation, dating from 76.5 to 75.5 million years ago. Discovery and nami ...

'', ''

Styracosaurus ''Styracosaurus'' ( ; meaning "spiked lizard" from the Ancient Greek / "spike at the butt-end of a spear-shaft" and / "lizard") is an extinct genus of herbivorous ceratopsian dinosaur from the Late Cretaceous (Campanian stage) of North America. ...

'', and ''

Anchiceratops ''Anchiceratops'' ( ) is an extinct genus of chasmosaurinae, chasmosaurine ceratopsid dinosaur that lived approximately 72 to 71 million years ago during the latter part of the Cretaceous Period (geology), Period in what is now Alberta, Canada. ' ...

''.

History of study

The holotype of ''Titanoceratops'' was collected from the upper

or the lower

in July 1941, by a field crew consisting J. Willis Stovall, his student Wann Langston Jr., and Donald E. Savage. The precise location of the quarry is no longer known. The holotype specimen consists of most of the fore and hindlimbs, some vertebrae, a fairly complete skull with only one small section of the frill, and partial lower jaws. The bones, being preserved in a fine-grained shale, were crushed and fragile, and so the skeleton was initially considered unsuitable for mounting. Later, however, the fossils were prepared and the skeleton put on display at the Oklahoma Museum of Natural History. In 1998, the specimen was described by Thomas Lehman as an aberrant and unusually large individual of ''

Pentaceratops sternbergii ''Pentaceratops'' ("five-horned face") is a genus of herbivorous ceratopsid dinosaur from the late Cretaceous Period of what is now North America. Fossils of this animal were first discovered in 1921, but the genus was named in 1923 when its typ ...

'', previously described from the same area. The specimen was later reinterpreted as a member of the Triceratopsini, the group including ''Triceratops'', by

and given the name ''Titanoceratops ouranos'' in

2011 The year marked the start of a Arab Spring, series of protests and revolutions throughout the Arab world advocating for democracy, reform, and economic recovery, later leading to the depositions of world leaders in Tunisia, Egypt, and Yemen ...

. The name ''Titanoceratops'' is derived from the

Titan Titan most often refers to: * Titan (moon), the largest moon of Saturn * Titans, a race of deities in Greek mythology Titan or Titans may also refer to: Arts and entertainment Fictional entities Fictional locations * Titan in fiction, fictiona ...

'', a mythical race of giants, ''keras'' (κέρας), meaning "horn", and ''ops'' (ὤψ), "face". The species name ''ouranos'', refers to

, the father of the Titan race. Longrich's re-interpretation would have major implications for the evolutionary history and biogeography of chasmosaurine dinosaurs. Previously, the origins of ''Triceratops'' were poorly known. Until the Longrich's re-interpretation of ''Titanoceratops'', ''Eotriceratops'' was thought to be the oldest known triceratopsin, and only dated to 68 million years old, from the uppermost region of the

Horseshoe Canyon Formation The Horseshoe Canyon Formation is a stratigraphic unit of the Western Canada Sedimentary Basin in southwestern Alberta. It takes its name from Horseshoe Canyon, an area of badlands near Drumheller. The Horseshoe Canyon Formation is part of th ...

. No

triceratopsins were known, so it appeared as if the group evolved in the Maastrichtian. If ''Titanoceratops'' is a member of this group, it would demonstrate that they evolved millions of years earlier than previously thought, and it would imply a five million year long gap in the fossil record and ghost lineage leading to ''Eotriceratops''. However, several subsequent studies have cast doubt on the hypothesis that ''Titanoceratops'' is a triceratopsin.

Classification

OMNH 10165 is a particularly large chasmosaurine fossil, which Lehman originally assigned to the genus ''Pentaceratops'', believing that it was a particularly large and old specimen. A 2011 study by Longrich disagreed with this interpretation, concluding that it was actually a distinct genus, which he named ''Titanoceratops''. Longrich interpreted the specimen as sharing more characteristics with ''Triceratops'' and ''Torosaurus'' than with ''Pentaceratops'', and he named a new group, Triceratopsini, to contain all of them. Longrich used the following features to distinguish the specimen from other chasmosaurines: the possession of thin squamosals (''Triceratops''); an unsealed parietal fenestrae (''Triceratops''); an epijugal resembling a hornlike structure (''Triceratops''); a narrow median bar of the parietal (''Triceratops'', ''Torosaurus''); a narial strut oriented vertically with a narrow base (''Triceratops'', ''Torosaurus''); an enlarged epoccipital on the rear end of the squamosal (''Triceratops'', ''Torosaurus'', ''Eotriceratops''); an extremely enlarged premaxillary fossa (''Triceratops'', ''Torosaurus'', ''Eotriceratops''); and in lacking a narial process of the premaxilla that is dorsally inflected (''Triceratops'', ''Torosaurus'', ''Eotriceratops''). Titanoceratops from the late Cretaceous

Lehman ignored Longrich's reclassification in his own subsequent publications. As part of a 2020 study by Fowler and Freedman Fowler, the authors critically re-evaluated the evidence that ''Titanoceratops'' was a distinct genus. They agreed with Lehman's original assessment, that the features in the specimen that appeared unique were likely due simply to advanced age and unusually large size. Pending a full re-evaluation of the specimen by other researchers, Fowler and Freedman Fowler opted to consider OMNH 10165 simply a large ''Pentaceratops''.

Paleoecology

Sabalites fossil palm leaf by Nick Longrich

''Titanoceratops'' is known from OMNH 10165, a skeleton from the lowermost Fruitland or uppermost Kirtland Formation. The Fruitland Formation is about thick, and consists of

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from ''shale'' by its lack of fissility.Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' New York, New York, ...

s, and abundant

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other Chemical element, elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal i ...

s deposited in a coastal floodplain. Fossil trees are abundant in the area from which the holotype was collected, suggesting a wet, well-forested environment. The Kirtland Formation, which conformably overlays the Fruitland, is approximately thick, and made up of sandstone,

siltstone Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility. Although its permeabil ...

, mudstone, and

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...

. Both formations are late Campanian in age. The Fossil Forest Member of the Fruitland is 74.11 ± 0.62 million years old, and the Hunter Wash Member of the Kirtland is between 73.37 ± 0.18 and 73.04 ± 0.25 million years in age. The two members combined make up the Hunter Wash local fauna. Therefore, ''Titanoceratops'' dates between 74 and 73 million years ago. The age ''Titanoceratops'' lived in is called the Kirtlandian land-vertebrate age, and it is characterized by the appearance of ''

''. A moderately diverse fauna is known from the Kirtland and Fruitland formations. Among the dinosaurs known from the Fruitland and Kirtland formations are the theropods '' Bistahieversor sealeyi'' (previously ''

Daspletosaurus ''Daspletosaurus'' ( ; meaning "frightful lizard") is a genus of tyrannosaurid dinosaur that lived in Laramidia between about 77 and 74.4 million years ago, during the Late Cretaceous Period. The genus ''Daspletosaurus'' contains three named ...

'' and ''

Albertosaurus ''Albertosaurus'' (; meaning "Alberta lizard") is a genus of large tyrannosaurid theropod dinosaur that lived in northwestern North America during the early to middle Maastrichtian age of the Late Cretaceous period, about 71 million yea ...

'' sp.), ''"

Saurornitholestes ''Saurornitholestes'' ("lizard-bird thief") is a genus of carnivorous dromaeosaurid theropod dinosaur from the late Cretaceous of Canada (Alberta and Saskatchewan) and the United States (Montana, New Mexico, Alabama, and South Carolina). Two spe ...

" robustus'', '' Paronychodon lacustris'', and an indeterminate ornithomimid (previously '' Ornithomimus antiquus''); the hadrosaurids ''

Anasazisaurus horneri ''Anasazisaurus'' ( ; "Anasazi lizard") is a genus of saurolophine hadrosaurid ("duckbill") ornithopod dinosaur that lived about 74 million years ago, in the Late Cretaceous period (geology), Period. It was found in the Farmington Member of the K ...

'' and ''

Parasaurolophus cyrtocristatus ''Parasaurolophus'' (; meaning "beside crested lizard" in reference to ''Saurolophus'') is a genus of Hadrosauridae, hadrosaurid "duck-billed" dinosaur that lived in what is now Laramidia, western North America and possibly Asia during the L ...

''; the pachycephalosaur '' Stegoceras novomexicanum'' (previously ''S. validum''); the ankylosaur '' Nodocephalosaurus kirtlandensis''; and the ceratopsians ''Pentaceratops sternbergii'' and an unidentified

centrosaurine Centrosaurinae (from the Greek, meaning "pointed lizards") is a subfamily of ceratopsid, a group of large quadrupedal ornithischian dinosaur. Centrosaurine fossil remains are known primarily from the northern region of Laramidia (modern day Alber ...

. Non-dinosaurian fauna include the

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

es '' Myledaphus bypartitus'', and '' Melvius chauliodous''; the

turtle Turtles are reptiles of the order (biology), order Testudines, characterized by a special turtle shell, shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Crypt ...

s '' Denazinemys ornata'', '' Denazinemys nodosa'', '' Boremys grandis'', '' Neurankylus baeuri'', ''

Adocus bossi ''Adocus'' is an extinct genus of aquatic turtles belonging to the family Adocidae. Description Species of the genus ''Adocus'' had flattened and smoothly contoured shells with horny sculptured plates. The shells could reach a length of at l ...

'', '' Adocus kirtlandicus'', '' Basilemys nobilis'', '' Asperideretes ovatus'', "

Plastomenus ''Plastomenus'' is an extinct genus of turtle that inhabited western North America during the early Paleogene period. Evolution ''Plastomenus'' belongs to the clade Pantrionychidae, represented by softshell turtles in modern times. It is the ...

" ''robustus'', and

Bothremydidae Bothremydidae is an extinct family of side-necked turtles (Pleurodira) known from the Cretaceous and Cenozoic. They are closely related to Podocnemididae, and are amongst the most widely distributed pleurodire groups, with their fossils having b ...

n. gen., ''barberl''; the

crocodylia Crocodilia () is an Order (biology), order of semiaquatic, predatory reptiles that are known as crocodilians. They first appeared during the Late Cretaceous and are the closest living relatives of birds. Crocodilians are a type of crocodylomorp ...

ns ''

Denazinosuchus kirtlandicus ''Denazinosuchus'' is a genus of goniopholidid mesoeucrocodylian. Its fossils have been recovered from the Upper Cretaceous Fruitland Formation and Kirtland Formation (late Campanian-early Maastrichtian) of the San Juan Basin, New Mexico. It is ...

'', '' Brachychampsa montana'', '' Deinosuchus rugosus'', and ''

Leidyosuchus ''Leidyosuchus'' (meaning " Leidy's crocodile") is an extinct genus of eusuchian, either an alligatoroid crocodilian or a stem-group crocodilian, from the Late Cretaceous of Alberta. It was named in 1907 by Lawrence Lambe, and the type species ...

'' sp.; and the

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

ians '' Paracimexomys judithae'', ''

Mesodma senecta ''Mesodma'' is an extinct genus of mammal, a member of the extinct order Multituberculata within the suborder Cimolodonta, family Neoplagiaulacidae. It lived during the upper Cretaceous and Paleocene Periods of what is now North America. The ear ...

'', ''

Mesodma ''Mesodma'' is an extinct genus of mammal, a member of the extinct order Multituberculata within the suborder Cimolodonta, family Neoplagiaulacidae. It lived during the upper Cretaceous and Paleocene Periods of what is now North America. The ear ...

'' sp., ''

Cimexomys ''Cimexomys'' is an extinct North American mammal that lived from the Upper Cretaceous to the Paleocene. For a while, it shared the world with dinosaurs, but outlived them. It was a member of the extinct order Multituberculata and lies within the ...

'' sp., '' Cinemoxys antiquus'', '' Kimbetohia campi'', '' Cimolodon electus'', ''

Meniscoessus intermedius ''Meniscoessus'' is a genus of extinct multituberculates from the Upper Cretaceous Period that lived in North America. It is a member of the order Multituberculata, belonging to the suborder Cimolodonta and family Cimolomyidae. The multituber ...

'', '' Essonodon'' sp., '' Alphadon marshi'', '' Alphadon wilsoni'', ''

Alphadon ''Alphadon'' is an extinct genus of small, primitive mammal that was a member of the metatherians, a group of mammals that includes modern-day marsupials. Its fossils were first discovered and named by George Gaylord Simpson in 1929. Description ...

'' sp. A, ''Alphadon'' sp. B, ''Alphadon''? sp., '' Pediomys cooki''; ''

Gypsonictops ''Gypsonictops'' is an extinct genus of leptictidan mammals of the family Gypsonictopidae, which was described in 1927 by George Gaylord Simpson. Species in this genus were small mammals and the first representatives of the order Leptictida, tha ...

'' sp., ''

Cimolestes ''Cimolestes'' (from Ancient Greek , 'chalk robber') is a genus of early eutherians with a full complement of teeth adapted for eating insects and other small animals. Paleontologists have disagreed on its relationship to other mammals, in part b ...

'' sp., and an indeterminate eucosmodontid. ''Titanoceratops'' supports the idea that late Cretaceous dinosaur faunas were highly endemic, with distinct species found in the Southern Great Plains of New Mexico, and the Northern Great Plains of Montana and Canada. Despite extensive sampling to the north in the Dinosaur Park Formation and Two Medicine Formation, triceratopsins are unknown there. This implies that the triceratopsins originally evolved in the south, then spread north in the Maastrichtian.

References

External links

The Discovery of Titanoceratops - Nick Longrich
{{Taxonbar, from=Q134986 Chasmosaurinae Dinosaur genera Campanian dinosaurs Kirtland Formation Taxa named by Nicholas R. Longrich Fossil taxa described in 2011 Dinosaurs of the United States

Description

History of study

Classification

Paleoecology

See also

References

External links