''Nedoceratops'' (meaning "insufficient horned face") is a controversial
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
ceratopsid dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...
from the
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger 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 ''creta'', the ...
period
Period may refer to:
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* Era, a length or span of time
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* Period (music), a concept in musical composition
* Periodic sentence (or rhetorical period), a concept ...
Lance Formation
The Lance (Creek) Formation is a division of Late Cretaceous (dating to about 69 - 66 Ma) rocks in the western United States. Named after Lance Creek, Wyoming, the microvertebrate fossils and dinosaurs represent important components of the late ...
of
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
. It is known only from a single
skull
The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, the ...
discovered in
Wyoming
Wyoming () is a U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the south ...
. Its status is the subject of ongoing debate among
paleontologist
Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...
s: some authors consider ''Nedoceratops'' a valid, distinct taxon, while others consider it to be an unusual specimen of ''
Triceratops
''Triceratops'' ( ; ) is a genus of herbivore, herbivorous Chasmosaurinae, chasmosaurine Ceratopsidae, ceratopsid dinosaur that first appeared during the late Maastrichtian stage of the Late Cretaceous Period (geology), period, about 68 m ...
''.
History of discovery
![Nedoceratops hatcheri 2](https://upload.wikimedia.org/wikipedia/commons/9/9b/Nedoceratops_hatcheri_2.jpg)
The nearly complete skull USNM 2412, the holotype specimen of ''Nedoceratops hatcheri'', was found in eastern Wyoming in 1891, in
Niobrara County near
Lightning Creek.
The paper that described ''Nedoceratops'' was originally part of
O. C. Marsh
Othniel Charles Marsh (October 29, 1831 – March 18, 1899) was an American professor of Paleontology in Yale College and President of the National Academy of Sciences. He was one of the preeminent scientists in the field of paleontology. Among h ...
's
magnum opus
A masterpiece, ''magnum opus'' (), or ''chef-d’œuvre'' (; ; ) in modern use is a creation that has been given much critical praise, especially one that is considered the greatest work of a person's career or a work of outstanding creativity, ...
, his Ceratopsidae
monograph
A monograph is a specialist work of writing (in contrast to reference works) or exhibition on a single subject or an aspect of a subject, often by a single author or artist, and usually on a scholarly subject.
In library cataloging, ''monograph ...
. Unfortunately, Marsh died (1899) before the work was completed, and
John Bell Hatcher
John Bell Hatcher (October 11, 1861 – July 3, 1904) was an American paleontologist and fossil hunter known as the "king of collectors" and best known for discovering ''Torosaurus'' and ''Triceratops'', two genera of dinosaurs described by Ot ...
endeavored to complete the ''Triceratops'' section. However, he died of
typhus
Typhus, also known as typhus fever, is a group of infectious diseases that include epidemic typhus, scrub typhus, and murine typhus. Common symptoms include fever, headache, and a rash. Typically these begin one to two weeks after exposure.
...
in 1904 at the age of 42, leaving the paper still incomplete. It fell to
Richard Swann Lull
Richard Swann Lull (November 6, 1867 – April 22, 1957) was an American paleontologist and Sterling Professor at Yale University who is largely remembered now for championing a non-Darwinian view of evolution, whereby mutation(s) could unl ...
to complete the monograph in 1905, publishing Hatcher's description of a skull separately and giving it the name ''Diceratops hatcheri'';
''Diceratops'' means "two horned face."
Since the ''Diceratops'' paper had been written by Hatcher, and Lull had only contributed the name and published the paper after Hatcher's death, Lull was not quite as convinced of the distinctiveness of ''Diceratops'', thinking it primarily pathological
Pathology is the study of the causal, causes and effects of disease or injury. The word ''pathology'' also refers to the study of disease in general, incorporating a wide range of biology research fields and medical practices. However, when us ...
. By 1933, Lull had had second thoughts about ''Diceratops'' being a distinct genus and he put it in a subgenus of ''Triceratops
''Triceratops'' ( ; ) is a genus of herbivore, herbivorous Chasmosaurinae, chasmosaurine Ceratopsidae, ceratopsid dinosaur that first appeared during the late Maastrichtian stage of the Late Cretaceous Period (geology), period, about 68 m ...
'': ''Triceratops'' (''Diceratops'') ''hatcheri'', including ''T. obtusus''; largely attributing its differences to being that of an aged individual.[
Because the ''Diceratops'' name was already in use for a ]hymenoptera
Hymenoptera is a large order (biology), order of insects, comprising the sawfly, sawflies, wasps, bees, and ants. Over 150,000 living species of Hymenoptera have been described, in addition to over 2,000 extinct ones. Many of the species are Par ...
n (Foerster, 1868), Andrey Sergeevich Ukrainsky gave the animal its current name ''Nedoceratops'' in 2007.[Ukrainsky, A.S. (2007)]
"A new replacement name for ''Diceratops'' Lull, 1905 (Reptilia: Ornithischia: Ceratopsidae)."
''Zoosystematica Rossica'', 16(2), 20 December 2007: 292. Unaware that Ukrainsky had already renamed the animal, Octávio Mateus
Octávio Mateus (born 1975) is a Portuguese dinosaur paleontologist and biologist Professor of Paleontology at the Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa. He graduated in Universidade de Évora and received his PhD at U ...
coined another new name for it in 2008, ''Diceratus''.[Ukrainsky, A.S. (2009). "Sinonimiya rodov ''Nedoceratops'' Ukrainsky, 2007 i ''Diceratus'' Mateus, 2008 (Reptilia: Ornithischia: Ceratopidae)." ''Paleontologicheskii zhurnal'', 2009(1): 108. Translated as: Ukrainsky, A.S. (2009)]
"Synonymy of the genera ''Nedoceratops'' Ukrainsky, 2007 and ''Diceratus'' Mateus, 2008 (Reptilia: Ornithischia: Ceratopidae)."
''Paleontological Journal'', 2009 43(1):116. ''Diceratus'' is thus a junior synonym
The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently.
* In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linna ...
of ''Nedoceratops''.
''Nedoceratops'' means "insufficient horned face". The "nedo" is the Russian prefix meaning "insufficient". The suffix common among ceratopsia
Ceratopsia or Ceratopia ( or ; Greek: "horned faces") is a group of herbivorous, beaked dinosaurs that thrived in what are now North America, Europe, and Asia, during the Cretaceous Period, although ancestral forms lived earlier, in the Jurassic. ...
ns, "ceratops", means "horned face". It was named in reference to its lack of a nasal horn.
Description
The nearly complete skull known as USNM 2412 is the only fossil attributed to ''Nedoceratops hatcheri''. Superficially, it resembles that of ''Triceratops'', but on closer examination, it differs: specifically, the brow horns stand almost vertically compared to typical ''Triceratops'' skulls, and there also are several holes in the frill (a unique feature of ''Triceratops'' proper is that it has a solid, unperforated fill). However, at least some of these holes show evidence that they are the result of injury or disease.[ The nasal horn of this specimen is low and rounded, compared with the larger, pointed nose horns of typical ''Triceratops'' specimens,][ though this feature appears to be within the known range of individual variation for ''Triceratops''.]
Classification
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 ...
is ''Nedoceratops hatcheri''. ''Nedoceratops'' belonged to the Ceratopsia (the name is Latinised Greek
Greek may refer to:
Greece
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 ...
for "horned faces"), a group of herbivorous dinosaurs with parrot
Parrots, also known as psittacines (), are birds of the roughly 398 species in 92 genera comprising the order Psittaciformes (), found mostly in tropical and subtropical regions. The order is subdivided into three superfamilies: the Psittacoid ...
-like beaks which thrived in North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
and Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...
during the Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...
Period, which ended roughly 66 million years ago. All ceratopsians became extinct at the end of this era.[
Several authors have suggested that ''Nedoceratops'' may be directly ancestral to ''Triceratops'', or perhaps its nearest relative. An ongoing debate concerns the status of ''Triceratops'', '']Torosaurus
''Torosaurus'' ("perforated lizard", in reference to the large openings in its frill) is a genus of herbivorous ceratopsid dinosaur that lived during the late Maastrichtian stage of the Cretaceous period, between 68 and 66 million years ago, th ...
'', and ''Nedoceratops''. In a series of publications, John B. Scannella and John R. Horner
John is a common English name and surname:
* John (given name)
* John (surname)
John may also refer to:
New Testament
Works
* Gospel of John, a title often shortened to John
* First Epistle of John, often shortened to 1 John
* Second E ...
(2010[ and 2011]) and claimed that the USNM 2412 skull (i.e., of ''Nedoceratops'') belonged to a "young adult" ''Triceratops''.[ Evidence for this hypothesis included the shapes of the ]epoccipital
Ceratopsia or Ceratopia ( or ; Greek: "horned faces") is a group of herbivorous, beaked dinosaurs that thrived in what are now North America, Europe, and Asia, during the Cretaceous Period, although ancestral forms lived earlier, in the Jurassic. ...
and 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 ancestral co ...
bones, and a neck frill
A neck frill is the relatively extensive margin seen on the back of the heads of reptiles with either a bony support such as those present on the skulls of dinosaurs of the suborder Marginocephalia or a cartilaginous one as in the frill-necked ...
(parietal bone) that had "incipient" openings (contrasting with no openings in subadult ''Triceratops'' and large openings in adult ''Triceratops'' formerly assigned to ''Torosaurus
''Torosaurus'' ("perforated lizard", in reference to the large openings in its frill) is a genus of herbivorous ceratopsid dinosaur that lived during the late Maastrichtian stage of the Cretaceous period, between 68 and 66 million years ago, th ...
'').[ These authors suggested that all three "genera" actually represent different aged individuals of ''Triceratops''.][ In 2012, Farke proposed a counterargument, and suggested that the bone surface texture and shape of the horns of ''Nedoceratops'' indicate an "old adult".][ A follow-up study by Leonardo Maiorino and colleagues in 2013] using morphometrics
Morphometrics (from Greek μορϕή ''morphe'', "shape, form", and -μετρία ''metria'', "measurement") or morphometry refers to the quantitative analysis of ''form'', a concept that encompasses size and shape. Morphometric analyses are co ...
found support for ''Triceratops'' and ''Torosaurus'' being distinct, valid taxa, with ''Nedoceratops'' occupying variable positions with respect to the other two but generally outside the range of variation, concluding that "the size of USNM 2412 is a plausible intermediate, but the shape is not."
Another supposed difference between ''Nedoceratops'' and fossils referred to ''Triceratops horridus'' is the remarkably short, rounded nasal "horn". Scanella and Horner proposed that the nasal horn of the USNM 2412 skull could have been lost when the animal was alive or when it became fossilized.[ However, it has been noted the horns of ceratopsids show a great deal of variation between age groups and individuals, and some specimens more solidly attributed to ''T. horridus'' have a similar nasal horn shape. In most features- the short, saddle-shape frill, the s-shaped snout- the animal closely resembles ''Triceratops horridus''.]
It has been noted that many of the features that seem to separate ''Nedoceratops'' from ''Triceratops'', and specifically ''Triceratops horridus'', may be the result of pathology, injury, and/or deformation of the skull after burial. Two of the features that have been used to diagnose Nedoceratops - the position of the squamosal, and the upright brow horns- are seen on one side of the skull, but not the other. This, along with the fact that the entire skull can be seen to be twisted when seen head-on, have been used to argue that these features result from post-mortem distortion of the fossil, rather than reflecting the anatomy of the animal during life. Furthermore, the presence of numerous holes in the frill suggests pathology due to injury or illness, the supposedly unique 'parietal fenestrae' may therefore be the result of an injury. Tanke & Farke (2007) noted that the supposed parietal fenestra had an irregular shape with swollen margins and an irregularly vascularized texture. This is similar to a parietal hole, also interpreted as the result of an injury by Marshall & Barreto (2001), in a specimen of ''Torosaurus''. Unfortunately, the frill is only preserved on one side, which makes it difficult to test this hypothesis.
References
External links
{{Taxonbar, from=Q132602
Chasmosaurines
Late Cretaceous dinosaurs of North America
Fossil taxa described in 2007
Maastrichtian life
Lance fauna
Paleontology in Wyoming
Controversial dinosaur taxa
Maastrichtian genus first appearances
Maastrichtian genus extinctions
Ornithischian genera