''Zuniceratops'' ('Zuni-horned face') is a genus of

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 ...

s that lived during the

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), ...

stage of 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 ...

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 ...

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

. Only a single species is known, ''Zuniceratops christopheri''.

History of discovery

Zuniceratops christopheri 1 salt lake city

''Zuniceratops'' was discovered in 1996, by eight-year-old Christopher James Wolfe, son of

paleontologist Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geolo ...

Douglas G. Wolfe, in the

Moreno Hill Formation The Moreno Hill Formation is a geological formation in western New Mexico whose strata were deposited in the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.Weishampel, David B; et al. (2004). ...

in west-central New Mexico where one skull and the bones from several individuals have been found. This discovery of ''Zuniceratops'' bonebed has been suggested as one of the evidence for the claim that grouping behavior could be a

synapomorphic In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to hav ...

trait for ceratopsians. In 2001, a bone believed to be a

squamosal The squamosal is a skull bone found in most reptiles, amphibians, and birds. In fishes, it is also called the pterotic bone. In most tetrapods, the squamosal and quadratojugal bones form the cheek series of the skull. The bone forms an ancestra ...

has since been found to be an

ischium The ischium (; : is ...

of a ''

Nothronychus ''Nothronychus'' (meaning "slothful claw") is a genus of therizinosaurid theropod dinosaurs that lived in North America during the Late Cretaceous period. The type species, ''Nothronychus mckinleyi'', was described by James Kirkland and Dougla ...

''. The holotype specimen, MSM P2101, is either a juvenile or a subadult, while other specimens like MSM P2101 and MSM P3812 belong to adults. The skull is long and low with no nasal horn, but bears a well-developed pair of brow horns that are similar to those of chasmosaurs and primitive centrosaurs, showing that brow horns are

plesiomorphic In phylogenetics, a plesiomorphy ("near form") and symplesiomorphy are synonyms for an ancestral character shared by all members of a clade, which does not distinguish the clade from other clades. Plesiomorphy, symplesiomorphy, apomorphy, an ...

traits.

Description

''Zuniceratops'' was a relatively small ceratopsian, measuring about long and weighing around . The basal skull length is estimated up to . The partial proximal parietal is shown to have an inverted "T" shape, as in ''

Protoceratops ''Protoceratops'' (; ) is a genus of small protoceratopsid dinosaurs that lived in Asia during the Late Cretaceous, around 75 to 71 million years ago. The genus ''Protoceratops'' includes two species: ''P. andrewsi'' and the larger ''P. hellenik ...

''. Although the first specimen discovered had single-rooted teeth (unusual for ceratopsians), larger fossils had double-rooted teeth, showing that the teeth became double-rooted with age and that it is a

trait.

Classification

''Zuniceratops'' is an example of the evolutionary transition between early ceratopsians and the later, larger ceratopsids that had very large horns and frills, supporting the theory that the lineage of ceratopsian dinosaurs may have been

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

n in origin. Re-examinations of ''

Turanoceratops ''Turanoceratops'' ("Turan horned face") is a genus of herbivorous ceratopsian dinosaur from the late Cretaceous Bissekty Formation of Uzbekistan. The fossils dated from the mid-late Turonian stage, roughly 90 million years ago. The skull bore a ...

'' and ''Zuniceratops'', which are known as two critical ceratopsian taxa regarding the evolutionary history of ceratopsids, showed that the origin of ceratopsids is unrelated to, and older than the fossil record of ''Protoceratops'' and relatives. Phylogenetic analysis reveal that ''Zuniceratops'' is a non-

ceratopsid Ceratopsidae (sometimes spelled Ceratopidae) is a family of ceratopsian dinosaurs including ''Triceratops'', '' Centrosaurus'', and '' Styracosaurus''. All known species were quadrupedal herbivores from the Upper Cretaceous. All but one species are ...

neoceratopisan, closely related to ''

'':

Paleoenvironment

Specimens of ''Zuniceratops'' are known from the

which documents a time of tectonic upheaval, volcanic activities, humid paleoclimate, and North American coastal margin shifts. Other dinosaurs fossils recovered from this formation are ''

Suskityrannus ''Suskityrannus'' (meaning "coyote tyrant", ''suski'' meaning "coyote" in Zuni) is a genus of small tyrannosauroid theropod from the Late Cretaceous in southern Laramidia. It contains a single species, ''Suskityrannus hazelae'', and the type s ...

'', ''

'', '' Jeyawati'', and undescribed

ankylosaur Ankylosauria is a group of herbivorous dinosaurs of the clade Ornithischia. It includes the great majority of dinosaurs with armor in the form of bony osteoderms, similar to turtles. Ankylosaurs were bulky quadrupeds, with short, powerful l ...

remains. Three groups of turtle fossils have been reported: a

baenid Baenidae is an extinct family of paracryptodiran turtles known from the Early Cretaceous to Eocene of North America. While during the Early Cretaceous they are found across North America, during the Late Cretaceous they are only found in Laramidi ...

''Edowa'', a helochelydrid ''

Naomichelys ''Naomichelys'' is an extinct genus of helochelydrid stem turtle known from the Cretaceous (Aptian-Campanian) of North America. It is the only member of the family known to be native to North America. Distribution ''Naomichelys'' is known nume ...

'' and an indeterminate

trionychid Trionychidae is a family of turtles, commonly known as softshell turtles or simply softshells. The family was described by Leopold Fitzinger in 1826. Softshells include some of the world's largest freshwater turtles, though many can adapt to liv ...

. Other vertebrate fossils include

crocodyliform Crocodyliformes is a clade of Crurotarsi, crurotarsan archosaurs, the group often traditionally referred to as "crocodilians". They are the first members of Crocodylomorpha to possess many of the features that define later relatives. They are the ...

teeth, amiid teeth and

gar Gars are an ancient group of ray-finned fish in the family Lepisosteidae. They comprise seven living species of fish in two genera that inhabit fresh, brackish, and occasionally marine waters of eastern North America, Central America and Cuba ...

scales.

References

*Wolfe, D. G. (2000). New information on the skull of ''Zuniceratops christopheri'', a neoceratopsian dinosaur from the Cretaceous Moreno Hill Formation, New Mexico. pp. 93–94, in S. G. Lucas and A. B. Heckert, eds. Dinosaurs of New Mexico. New Mexico Museum of Natural History and Science Bulletin No. 17. {{Taxonbar, from=Q131773 Ceratopsia Dinosaur genera Turonian dinosaurs Dinosaurs of the United States Fossil taxa described in 1998 Taxa named by James I. Kirkland

History of discovery

Description

Classification

Paleoenvironment

See also

References