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84-462: Triceratops ( / t r aɪ ˈ s ɛr ə t ɒ p s / try- SERR -ə-tops ; lit.   ' three-horned face ' ) is a genus of chasmosaurine ceratopsian dinosaur that lived during the late Maastrichtian age of the Late Cretaceous period , about 68 to 66 million years ago in what is now western North America. It was one of the last-known non-avian dinosaurs and lived until

168-557: A species : see Botanical name and Specific name (zoology) . The rules for the scientific names of organisms are laid down in the nomenclature codes , which allow each species a single unique name that, for animals (including protists ), plants (also including algae and fungi ) and prokaryotes ( bacteria and archaea ), is Latin and binomial in form; this contrasts with common or vernacular names , which are non-standardized, can be non-unique, and typically also vary by country and language of usage. Except for viruses ,

252-596: A chasmosaurine. The cladogram below follows Longrich (2014), who named a new species of Pentaceratops , and included nearly all species of chasmosaurine. Mercuriceratops Judiceratops Chasmosaurus Mojoceratops Agujaceratops Pentaceratops aquilonius Williams Fork chasmosaur Pentaceratops sternbergii Utahceratops Kosmoceratops Anchiceratops Almond Formation chasmosaur Bravoceratops Coahuilaceratops Arrhinoceratops Titanoceratops Torosaurus Triceratops For many years after its discovery,

336-510: A fairly primitive structure when compared to other quadrupedal dinosaurs, such as thyreophorans and many sauropods . In those two groups, the forelimbs of quadrupedal species were usually rotated so that the hands faced forward with palms backward ("pronated") as the animals walked. Triceratops , like other ceratopsians and related quadrupedal ornithopods (together forming the Cerapoda ), walked with most of their fingers pointing out and away from

420-486: A family of large, mostly North American ceratopsians . The exact relationship of Triceratops among the other ceratopsids has been debated over the years. Confusion stemmed mainly from the combination of a short, solid frill (similar to that of Centrosaurinae ), with long brow horns (more akin to Chasmosaurinae ). In the first overview of ceratopsians, R. S. Lull hypothesized the existence of two lineages, one of Monoclonius and Centrosaurus leading to Triceratops ,

504-422: A heavily forested habitat. Cope later (in 1873) described the skeleton as "the wreck of one of the princes among giants." Cope and his team eventually recovered complete hip bones, sacral vertebrae, and several ribs from the animal. Later in 1872, Cope published a description and name for the animal, Agathaumas sylvestris , or "marvelous forest-dweller," in reference to its great size and the environment revealed in

588-407: A large skull relative to its body size, among the largest of all land animals. The largest-known skull, specimen MWC 7584 (formerly BYU 12183), is estimated to have been 2.5 meters (8.2 ft) in length when complete and could reach almost a third of the length of the entire animal. The front of the head was equipped with a large beak in front of its teeth. The core of the top beak was formed by

672-643: A later homonym of a validly published name is a nomen illegitimum or nom. illeg. ; for a full list refer to the International Code of Nomenclature for algae, fungi, and plants and the work cited above by Hawksworth, 2010. In place of the "valid taxon" in zoology, the nearest equivalent in botany is " correct name " or "current name" which can, again, differ or change with alternative taxonomic treatments or new information that results in previously accepted genera being combined or split. Prokaryote and virus codes of nomenclature also exist which serve as

756-744: A lesser or greater degree from the original holotype. This variation is unsurprising, given that Triceratops skulls are large three-dimensional objects from individuals of different ages and both sexes that which were subjected to different amounts and directions of pressure during fossilization. In the first attempt to understand the many species, Richard Swann Lull found two groups, although he did not say how he distinguished them. One group composed of T. horridus , T. prorsus , and T. brevicornus ('the short-horned'). The other composed of T. elatus and T. calicornis . Two species ( T. serratus and T. flabellatus ) stood apart from these groups. By 1933, alongside his revision of

840-621: A long time and redescribed as new by a range of subsequent workers, or if a range of genera previously considered separate taxa have subsequently been consolidated into one. For example, the World Register of Marine Species presently lists 8 genus-level synonyms for the sperm whale genus Physeter Linnaeus, 1758, and 13 for the bivalve genus Pecten O.F. Müller, 1776. Within the same kingdom, one generic name can apply to one genus only. However, many names have been assigned (usually unintentionally) to two or more different genera. For example,

924-409: A paper in which they proposed that there was only one species, Triceratops horridus . Part of their rationale was that there are generally only one or two species of any large animal in a region. To their findings, Thomas Lehman added the old Lull–Sternberg lineages combined with maturity and sexual dimorphism , suggesting that the T. horridus–T. prorsus–T. brevicornus lineage was composed of females,

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1008-409: A reference for designating currently accepted genus names as opposed to others which may be either reduced to synonymy, or, in the case of prokaryotes, relegated to a status of "names without standing in prokaryotic nomenclature". An available (zoological) or validly published (botanical) name that has been historically applied to a genus but is not regarded as the accepted (current/valid) name for

1092-578: A reference point in the definition of Dinosauria. Dinosaurs have been designated as all descendants of the most recent common ancestor of Triceratops and modern birds . Furthermore, Ornithischia has been defined as those dinosaurs more closely related to Triceratops than to modern birds. Genus The composition of a genus is determined by taxonomists . The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including

1176-404: A separate genus, represents Triceratops in its mature form. This view has still been highly disputed and much more data is needed to settle this ongoing debate. Triceratops has been documented by numerous remains collected since the genus was first described in 1889 by American paleontologist Othniel Charles Marsh . Specimens representing life stages from hatchling to adult have been found. As

1260-442: A separate genus. She found that T. horridus and several other species belonged together and that T. prorsus and T. brevicornus stood alone. Since there were many more specimens in the first group, she suggested that this meant the two groups were two species. It is still possible to interpret the differences as representing a single species with sexual dimorphism. In 2009, John Scannella and Denver Fowler supported

1344-410: A special rostral bone. Behind it, the premaxillae bones were located, embayed from behind by very large, circular nostrils. In chasmosaurines, the premaxillae met on their midline in a complex bone plate, the rear edge of which was reinforced by the "narial strut". From the base of this strut, a triangular process jutted out into the nostril. Triceratops differs from most relatives in that this process

1428-427: A taxon; however, the names published in suppressed works are made unavailable via the relevant Opinion dealing with the work in question. In botany, similar concepts exist but with different labels. The botanical equivalent of zoology's "available name" is a validly published name . An invalidly published name is a nomen invalidum or nom. inval. ; a rejected name is a nomen rejiciendum or nom. rej. ;

1512-455: A total of c. 520,000 published names (including synonyms) as at end 2019, increasing at some 2,500 published generic names per year. "Official" registers of taxon names at all ranks, including genera, exist for a few groups only such as viruses and prokaryotes, while for others there are compendia with no "official" standing such as Index Fungorum for fungi, Index Nominum Algarum and AlgaeBase for algae, Index Nominum Genericorum and

1596-399: A very sturdy build, with strong limbs, short hands with three hooves each, and short feet with four hooves each. The vertebral column consisted of ten neck, twelve back, ten sacral, and about forty-five tail vertebrae . The front neck vertebrae were fused into a syncervical. Traditionally, this was assumed to have incorporated the first three vertebrae, thus implying that the frontmost atlas

1680-594: Is a dubious taxon and cannot be referred beyond Ceratopsidae. based on stratigraphy it is likely a member of Triceratopsini. In 1897, paleoartist Charles R. Knight painted "Agathaumas sphenocerus" for an article in The Century Magazine under the supervision of Edward Drinker Cope . The nasal horn and brow horns were based on "Monoclonius" sphenocerus (possible synonym of Centrosaurus apertus ) and "Monoclonius" recurvicornis (unnamed genus similar to Einiosaurus ) respectively, which were found in

1764-596: Is discouraged by both the International Code of Zoological Nomenclature and the International Code of Nomenclature for algae, fungi, and plants , there are some five thousand such names in use in more than one kingdom. For instance, A list of generic homonyms (with their authorities), including both available (validly published) and selected unavailable names, has been compiled by the Interim Register of Marine and Nonmarine Genera (IRMNG). The type genus forms

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1848-460: Is estimated to have been 15 metres (49 ft) long and weighed 17.5 tonnes (17.2 long tons; 19.3 short tons), and was seen as the largest land animal known at the time of its discovery. It was the first ceratopsian known to science from more than teeth, though relatively little is known about it. The original specimen consisted only of the animal's hip bones, hip vertebrae and ribs, and because these bones vary little between ceratopsid species, it

1932-465: Is one of the most recognizable of all dinosaurs and the best-known ceratopsian. It was also one of the largest, measuring around 8–9 m (26–30 ft) long and weighing up to 6–10 t (5.9–9.8 long tons; 6.6–11.0 short tons). It shared the landscape with and was most likely preyed upon by Tyrannosaurus , though it is less certain that two adults would battle in the fanciful manner often depicted in museum displays and popular media. The functions of

2016-460: Is somewhat arbitrary. Although all species within a genus are supposed to be "similar", there are no objective criteria for grouping species into genera. There is much debate among zoologists about whether enormous, species-rich genera should be maintained, as it is extremely difficult to come up with identification keys or even character sets that distinguish all species. Hence, many taxonomists argue in favor of breaking down large genera. For instance,

2100-414: Is that the neck ribs only begin to lengthen with the ninth cervical vertebra. The rather short and high vertebrae of the back were, in its middle region, reinforced by ossified tendons running along the tops of the neural arches . The straight sacrum was long and adult individuals show a fusion of all sacral vertebrae. In Triceratops the first four and last two sacrals had transverse processes, connecting

2184-474: Is the type species , and the generic name is permanently associated with the type specimen of its type species. Should the specimen turn out to be assignable to another genus, the generic name linked to it becomes a junior synonym and the remaining taxa in the former genus need to be reassessed. In zoological usage, taxonomic names, including those of genera, are classified as "available" or "unavailable". Available names are those published in accordance with

2268-411: Is usually considered a nomen dubium . It is provisionally considered a synonym of Triceratops , but is difficult to compare to that genus because it is only known from postcranial remains. The holotype remains of Agathaumas were first found in 1872 in southwestern Wyoming . They were discovered by Fielding Bradford Meek and Henry Martyn Bannister while they were looking for fossil shells in

2352-551: The Cretaceous–Paleogene extinction event 66 million years ago. The name Triceratops , which means 'three-horned face', is derived from the Greek words trí- ( τρί- ) meaning 'three', kéras ( κέρας ) meaning 'horn', and ṓps ( ὤψ ) meaning 'face'. Bearing a large bony frill , three horns on the skull, and a large, four-legged body, exhibiting convergent evolution with bovines and rhinoceroses , Triceratops

2436-621: The International Code of Zoological Nomenclature ; the earliest such name for any taxon (for example, a genus) should then be selected as the " valid " (i.e., current or accepted) name for the taxon in question. Consequently, there will be more available names than valid names at any point in time; which names are currently in use depending on the judgement of taxonomists in either combining taxa described under multiple names, or splitting taxa which may bring available names previously treated as synonyms back into use. "Unavailable" names in zoology comprise names that either were not published according to

2520-799: The International Plant Names Index for plants in general, and ferns through angiosperms, respectively, and Nomenclator Zoologicus and the Index to Organism Names for zoological names. Totals for both "all names" and estimates for "accepted names" as held in the Interim Register of Marine and Nonmarine Genera (IRMNG) are broken down further in the publication by Rees et al., 2020 cited above. The accepted names estimates are as follows, broken down by kingdom: The cited ranges of uncertainty arise because IRMNG lists "uncertain" names (not researched therein) in addition to known "accepted" names;

2604-638: The Judith River Formation in Montana and named by Cope in 1889. The rest of the skull and body were based on an 1891 skeletal reconstruction of Triceratops prorsus by Othniel Charles Marsh . The armor was based on isolated elements from the Lance Formation in Wyoming that Marsh erroneously referred to Triceratops in 1891: the spines on the frill were a Denversaurus schlessmani cervical spine,

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2688-584: The Lance Formation near the Black Butte and Bitter Creek . Meek and Bannister were employed by Ferdinand Vandeveer Hayden 's Geological Survey of the Territories and notified paleontologist Edward Drinker Cope of the find. Cope himself searched the ridge near Black Butte and re-discovered Meek's site, finding huge bones protruding from the rocks near a coal vein. The bones were preserved in sand and clay sediments, packed with fossil sticks and leaves, indicating

2772-474: The T. calicornis–T. elatus lineage was made up of males, and the T. obtusus–T. hatcheri lineage was of pathologic old males. These findings were contested a few years later by paleontologist Catherine Forster , who reanalyzed Triceratops material more comprehensively and concluded that the remains fell into two species, T. horridus and T. prorsus , although the distinctive skull of T.  (" Nedoceratops ") hatcheri differed enough to warrant

2856-452: The archetypal ceratopsian, Triceratops is one of the most beloved, popular dinosaurs and has been featured in numerous films, postage stamps, and many other types of media. The first named fossil specimen now attributed to Triceratops is a pair of brow horns attached to a skull roof that were found by George Lyman Cannon near Denver , Colorado , in the spring of 1887. This specimen was sent to Othniel Charles Marsh , who believed that

2940-760: The formation from which it came from dated from the Pliocene and that the bones belonged to a particularly large and unusual bison , which he named Bison alticornis . He realized that there were horned dinosaurs by the next year, which saw his publication of the genus Ceratops from fragmentary remains, but he still believed B. alticornis to be a Pliocene mammal . It took a third and much more complete skull to fully change his mind. Although not confidently assignable, fossils possibly belonging to Triceratops were described as two taxa, Agathaumas sylvestris and Polyonax mortuarius , in 1872 and 1874, respectively, by Marsh's archrival Edward Drinker Cope . Agathaumas

3024-433: The frontal bones , a "double" skull roof was created. In Triceratops , some specimens show a fontanelle , an opening in the upper roof layer. The cavity between the layers invaded the bone cores of the brow horns. At the rear of the skull, the outer squamosal bones and the inner parietal bones grew into a relatively short, bony frill, adorned with epoccipitals in young specimens. These were low triangular processes on

3108-404: The platypus belongs to the genus Ornithorhynchus although George Shaw named it Platypus in 1799 (these two names are thus synonyms ) . However, the name Platypus had already been given to a group of ambrosia beetles by Johann Friedrich Wilhelm Herbst in 1793. A name that means two different things is a homonym . Since beetles and platypuses are both members of the kingdom Animalia,

3192-400: The "short-frilled" ceratopsids, but modern cladistic studies show it to be a member of Chasmosaurinae , which usually have long frills. Two species , T. horridus and T. prorsus , are considered valid today. Seventeen different species, however, have been named throughout history. Research published in 2010 concluded that the contemporaneous Torosaurus , a ceratopsid long regarded as

3276-477: The 1900s and 1930s, all of the members of Agathaumidae were found to be dubious, and the family name Ceratopsidae was preferred over Agathaumidae. Agathaumas itself was found to be a dubious Ceratopsid by Hatcher and Lull, as well as by John Ostrom and Peter Wellnhofer who placed it as Triceratops sp. Type: Species previously referred to Agathaumas : Unfortunately, due to the fragmentary nature of Agathaumas sylvestris ’ holotype specimen, Agathaumas

3360-570: The Canadian provinces of Saskatchewan and Alberta . After Triceratops was described, between 1889 and 1891, Hatcher collected another thirty-one of its skulls with great effort. The first species had been named T. horridus by Marsh. Its specific name was derived from the Latin word horridus meaning "rough" or "rugose", perhaps referring to the type specimen's rough texture, later identified as an aged individual. The additional skulls varied to

3444-469: The French botanist Joseph Pitton de Tournefort (1656–1708) is considered "the founder of the modern concept of genera". The scientific name (or the scientific epithet) of a genus is also called the generic name ; in modern style guides and science, it is always capitalised. It plays a fundamental role in binomial nomenclature , the system of naming organisms , where it is combined with the scientific name of

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3528-590: The Maastrichtian Denver Formation . The fossils only consisted of fragmentary horn cores, 3 dorsal vertebrae, and fragmentary limb elements. Polyonax has the same issue as Agathaumas , with the fragmentary remains non-assignable beyond Ceratopsidae. The Triceratops holotype , YPM 1820, was collected in 1888 from the Lance Formation of Wyoming by fossil hunter John Bell Hatcher , but Marsh initially described this specimen as another species of Ceratops . Cowboy Edmund B. Wilson had been startled by

3612-442: The base for higher taxonomic ranks, such as the family name Canidae ("Canids") based on Canis . However, this does not typically ascend more than one or two levels: the order to which dogs and wolves belong is Carnivora ("Carnivores"). The numbers of either accepted, or all published genus names is not known precisely; Rees et al., 2020 estimate that approximately 310,000 accepted names (valid taxa) may exist, out of

3696-426: The basis of several morphological features. Apart from the one feature of a shortened frill, Triceratops shares no derived traits with centrosaurines. Further research by Peter Dodson , including a 1990 cladistic analysis and a 1993 study using resistant-fit theta-rho analysis, or RFTRA (a morphometric technique which systematically measures similarities in skull shape), reinforces Triceratops ' placement as

3780-411: The body, the original condition for dinosaurs. This was also retained by bipedal forms, like theropods . In Triceratops , the weight of the body was carried by only the first three fingers of the hand, while digits 4 and 5 were vestigial and lacked claws or hooves. The phalangeal formula of the hand is 2-3-4-3-1, meaning that the first or innermost finger of the forelimb has two bones, the next has three,

3864-423: The deeper evolutionary origins of Triceratops and its close relatives remained largely obscure. In 1922, the newly discovered Protoceratops was seen as its ancestor by Henry Fairfield Osborn , but many decades passed before additional findings came to light. Recent years have been fruitful for the discovery of several antecedents of Triceratops . Zuniceratops , the earliest-known ceratopsian with brow horns,

3948-403: The epinasal. The skull also featured a pair of supraorbital "brow" horns approximately 1 meter (3.3 ft) long, with one above each eye. The jugal bones pointed downward at the rear sides of the skull and were capped by separate epijugals. With Triceratops , these were not particularly large and sometimes touched the quadratojugals. The bones of the skull roof were fused and by a folding of

4032-446: The form "author, year" in zoology, and "standard abbreviated author name" in botany. Thus in the examples above, the genus Canis would be cited in full as " Canis Linnaeus, 1758" (zoological usage), while Hibiscus , also first established by Linnaeus but in 1753, is simply " Hibiscus L." (botanical usage). Each genus should have a designated type , although in practice there is a backlog of older names without one. In zoology, this

4116-435: The form of trackways from horned dinosaurs and recent reconstructions of skeletons (both physical and digital) seem to show that Triceratops and other ceratopsids maintained an upright stance during normal locomotion, with the elbows flexed to behind and slightly bowed out, in an intermediate state between fully upright and fully sprawling, comparable to the modern rhinoceros. The hands and forearms of Triceratops retained

4200-402: The frill edge, representing separate skin ossifications or osteoderms . Typically, with Triceratops specimens, there are two epoccipitals present on each parietal bone, with an additional central process on their border. Each squamosal bone had five processes. Most other ceratopsids had large parietal fenestrae , openings in their frills, but those of Triceratops were noticeably solid, unless

4284-417: The frills and three distinctive facial horns on its head have inspired countless debates. Traditionally, these have been viewed as defensive weapons against predators. More recent interpretations find it probable that these features were primarily used in species identification, courtship, and dominance display, much like the antlers and horns of modern ungulates . Triceratops was traditionally placed within

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4368-727: The generic name (or its abbreviated form) still forms the leading portion of the scientific name, for example, Canis lupus lupus for the Eurasian wolf subspecies, or as a botanical example, Hibiscus arnottianus ssp. immaculatus . Also, as visible in the above examples, the Latinised portions of the scientific names of genera and their included species (and infraspecies, where applicable) are, by convention, written in italics . The scientific names of virus species are descriptive, not binomial in form, and may or may not incorporate an indication of their containing genus; for example,

4452-422: The genus Torosaurus represents mature Triceratops individuals, which it most likely does not. Under the frill, at the rear of the skull, a huge occipital condyle , up to 106 millimeters (4.2 in) in diameter, connected the head to the neck. The lower jaws were elongated and met at their tips in a shared epidentary bone, the core of the toothless lower beak. In the dentary bone, the tooth battery curved to

4536-676: The group now recognized as Ceratopsia until later in 1889, when Cope recognized that his genera Monoclonius and Polyonax were related due to Marsh's description of Triceratops fossils. Marsh had already named a group for the horned dinosaurs, Ceratopsidae, but Cope did not recognize this family name as he believed Ceratops could not be distinguished from other taxa; Cope erected a new name, Agathaumidae. Cope later named 2 more "Agathaumids", Manospondylus gigas and Claorhynchus trihedrus , based on fragmentary fossils in 1892, expanding his group to 5 genera. After reassessment by John Bell Hatcher , Richard Swann Lull , and Nelda Wright in

4620-432: The idea that a newly defined genus should fulfill these three criteria to be descriptively useful: Moreover, genera should be composed of phylogenetic units of the same kind as other (analogous) genera. The term "genus" comes from Latin genus , a noun form cognate with gignere ('to bear; to give birth to'). The Swedish taxonomist Carl Linnaeus popularized its use in his 1753 Species Plantarum , but

4704-446: The landmark 1907 Hatcher–Marsh–Lull monograph of all known ceratopsians, he retained his two groups and two unaffiliated species, with a third lineage of T. obtusus and T. hatcheri ('Hatcher's') that was characterized by a very small nasal horn. T. horridus–T. prorsus–T. brevicornus was now thought to be the most conservative lineage, with an increase in skull size and a decrease in nasal horn size. T. elatus–T. calicornis

4788-628: The largest component, with 23,236 ± 5,379 accepted genus names, of which 20,845 ± 4,494 are angiosperms (superclass Angiospermae). By comparison, the 2018 annual edition of the Catalogue of Life (estimated >90% complete, for extant species in the main) contains currently 175,363 "accepted" genus names for 1,744,204 living and 59,284 extinct species, also including genus names only (no species) for some groups. The number of species in genera varies considerably among taxonomic groups. For instance, among (non-avian) reptiles , which have about 1180 genera,

4872-576: The lizard genus Anolis has been suggested to be broken down into 8 or so different genera which would bring its ~400 species to smaller, more manageable subsets. Agathaumas See text Agathaumas ( / æ ɡ ə ˈ θ ɔː m ə s / ; "great wonder") is a dubious genus of a large ceratopsid dinosaur that lived in Wyoming during the Late Cretaceous (late Maastrichtian stage , 66 million years ago). The name comes from Ancient Greek : αγαν - 'much' and θαυμα - 'wonder'. It

4956-403: The most (>300) have only 1 species, ~360 have between 2 and 4 species, 260 have 5–10 species, ~200 have 11–50 species, and only 27 genera have more than 50 species. However, some insect genera such as the bee genera Lasioglossum and Andrena have over 1000 species each. The largest flowering plant genus, Astragalus , contains over 3,000 species. Which species are assigned to a genus

5040-428: The name could not be used for both. Johann Friedrich Blumenbach published the replacement name Ornithorhynchus in 1800. However, a genus in one kingdom is allowed to bear a scientific name that is in use as a generic name (or the name of a taxon in another rank) in a kingdom that is governed by a different nomenclature code. Names with the same form but applying to different taxa are called "homonyms". Although this

5124-400: The next has four, etc. Preserved skin from Triceratops is known. This skin consist of large scales, some of which exceed 100 millimetres (3.9 in) across, which have conical projections rising from their center. A preserved piece of skin from the frill of a specimen is also known, which consists of small polygonal basement scales. Triceratops is the best-known genus of Ceratopsidae ,

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5208-452: The other with Ceratops and Torosaurus , making Triceratops a centrosaurine as the group is understood today. Later revisions supported this view when Lawrence Lambe , in 1915, formally describing the first, short-frilled group as Centrosaurinae (including Triceratops ), and the second, long-frilled group as Chasmosaurinae. In 1949, Charles Mortram Sternberg was the first to question this position, proposing instead that Triceratops

5292-420: The outside to meet the battery of the upper jaw. At the rear of the lower jaw, the articular bone was exceptionally wide, matching the general width of the jaw joint. T. horridus can be distinguished from T. prorsus by having a shallower snout. Chasmosaurines showed little variation in their postcranial skeleton. The skeleton of Triceratops is markedly robust. Both Triceratops species possessed

5376-526: The provisions of the ICZN Code, e.g., incorrect original or subsequent spellings, names published only in a thesis, and generic names published after 1930 with no type species indicated. According to "Glossary" section of the zoological Code, suppressed names (per published "Opinions" of the International Commission of Zoological Nomenclature) remain available but cannot be used as the valid name for

5460-655: The remains were similar to the British reptile Cetiosaurus and very different from the corresponding elements of Hadrosaurus and Dryptosaurus ( Laelaps ). In 1882, Othniel Charles Marsh , Cope's rival in the Bone Wars, suggested that Agathaumas , along with Cionodon , another Cope taxon, was a Hadrosaurid. In 1883, with his description of the skull of Edmontosaurus ( Diclonius ), Cope also suggested that his taxa Agathaumas , Monoclonius , and Dysganus could be Hadrosaurids. Cope did not assign Agathaumas into

5544-577: The same rocks as its bones. The name Agathaumas has been cited as an example of Cope's excitement with this discovery, which he considered, at the time, as the largest known land animal that had ever lived. Several years later, with the discovery of the giant sauropod dinosaurs of the Morrison Formation , it became clear to him that British forms such as Cetiosaurus and Pelorosaurus were land animals. Cope originally did not know to what group Agathaumas belonged, though he noted that some of

5628-415: The scutes on the flank were indeterminate ankylosaurian osteoderms (either Denversaurus or Ankylosaurus magniventris ), and the spikes on the back were a Pachycephalosaurus wyomingensis squamosal horn. The name Agathaumas was arbitrarily used for Knight's depiction and no parts were based on A. sylvestris . His painting inspired a stop motion model created by Marcel Delgado that appeared in

5712-636: The separation of T. prorsus and T. horridus , noting that the two species are also separated stratigraphically within the Hell Creek Formation, indicating that they did not live together at the same time. Some of the following species are synonyms , as indicated in parentheses ("= T. horridus " or "= T. prorsus "). All the others are each considered a nomen dubium ( lit.   ' dubious name ' ) because they are based on remains too poor or incomplete to be distinguished from pre-existing Triceratops species. Triceratops

5796-410: The sight of a monstrous skull poking out of the side of a ravine. He tried to recover it by throwing a lasso around one of the horns. When it broke off, the skull tumbling to the bottom of the cleft, Wilson brought the horn to his boss. His boss was rancher and avid fossil collector Charles Arthur Guernsey, who just so happened to show it to Hatcher. Marsh subsequently ordered Hatcher to locate and salvage

5880-707: The skull. The holotype was first named Ceratops horridus . When further preparation uncovered the third nose horn, Marsh changed his mind and gave the piece the new generic name Triceratops ( lit.   ' three horn face ' ), accepting his Bison alticornis as another species of Ceratops . It would, however, later be added to Triceratops . The sturdy nature of the animal's skull has ensured that many examples have been preserved as fossils, allowing variations between species and individuals to be studied. Triceratops remains have subsequently been found in Montana and South Dakota (and more in Colorado and Wyoming), as well as

5964-497: The specific name particular to the wolf. A botanical example would be Hibiscus arnottianus , a particular species of the genus Hibiscus native to Hawaii. The specific name is written in lower-case and may be followed by subspecies names in zoology or a variety of infraspecific names in botany . When the generic name is already known from context, it may be shortened to its initial letter, for example, C. lupus in place of Canis lupus . Where species are further subdivided,

6048-412: The standard format for a species name comprises the generic name, indicating the genus to which the species belongs, followed by the specific epithet, which (within that genus) is unique to the species. For example, the gray wolf 's scientific name is Canis lupus , with Canis ( Latin for 'dog') being the generic name shared by the wolf's close relatives and lupus (Latin for 'wolf') being

6132-403: The taxon is termed a synonym ; some authors also include unavailable names in lists of synonyms as well as available names, such as misspellings, names previously published without fulfilling all of the requirements of the relevant nomenclatural code, and rejected or suppressed names. A particular genus name may have zero to many synonyms, the latter case generally if the genus has been known for

6216-566: The values quoted are the mean of "accepted" names alone (all "uncertain" names treated as unaccepted) and "accepted + uncertain" names (all "uncertain" names treated as accepted), with the associated range of uncertainty indicating these two extremes. Within Animalia, the largest phylum is Arthropoda , with 151,697 ± 33,160 accepted genus names, of which 114,387 ± 27,654 are insects (class Insecta). Within Plantae, Tracheophyta (vascular plants) make up

6300-402: The vertebral column to the pelvis, that were fused at their distal ends. Sacrals seven and eight had longer processes, causing the sacrum to have an oval profile in top view. On top of the sacrum, a neural plate was present formed by a fusion of the neural spines of the second through fifth vertebrae. Triceratops had a large pelvis with a long ilium . The ischium was curved downwards. The foot

6384-429: The virus species " Salmonid herpesvirus 1 ", " Salmonid herpesvirus 2 " and " Salmonid herpesvirus 3 " are all within the genus Salmonivirus ; however, the genus to which the species with the formal names " Everglades virus " and " Ross River virus " are assigned is Alphavirus . As with scientific names at other ranks, in all groups other than viruses, names of genera may be cited with their authorities, typically in

6468-523: Was a very large animal, measuring around 8–9 m (26–30 ft) in length and weighing up to 6–10 metric tons (6.6–11.0 short tons). A specimen of T. horridus named Kelsey measured 6.7–7.3 meters (22–24 ft) long, has a 2-meter (6.5 ft) skull, stood about 2.3 meters (7.5 ft) tall, and was estimated by the Black Hills Institute to weigh approximately 5.4 metric tons (6.0 short tons). Like all chasmosaurines , Triceratops had

6552-494: Was defined by having large brow horns and small nasal horns. Charles Mortram Sternberg made one modification by adding T. eurycephalus ('the wide-headed') and suggesting that it linked the second and third lineages closer together than they were to the T. horridus lineage. With time, the idea that the differing skulls might be representative of individual variation within one (or two) species gained popularity. In 1986, John Ostrom and Peter Wellnhofer published

6636-587: Was described in the late 1990s, and Yinlong , the first known Jurassic ceratopsian, was described in 2005. These new finds have been vital in illustrating the origins of ceratopsians in general, suggesting an Asian origin in the Jurassic and the appearance of truly horned ceratopsians by the beginning of the Late Cretaceous in North America. In phylogenetic taxonomy , the genus Triceratops has been used as

6720-423: Was hollowed out on the outer side. Behind the toothless premaxilla, the maxilla bore thirty-six to forty tooth positions, in which three to five teeth per position were vertically stacked. The teeth were closely appressed, forming a "dental battery" curving to the inside. The skull bore a single horn on the snout above the nostrils. In Triceratops , the nose horn is sometimes recognisable as a separate ossification,

6804-574: Was more closely related to Arrhinoceratops and Chasmosaurus based on skull and horn features, making Triceratops a chasmosaurine ("ceratopsine" in his usage) genus. He was largely ignored, with John Ostrom and later David Norman placing Triceratops within the Centrosaurinae. Subsequent discoveries and analyses, however, proved the correctness of Sternberg's view on the position of Triceratops , with Thomas Lehman defining both subfamilies in 1990 and diagnosing Triceratops as "ceratopsine" on

6888-570: Was named based on a pelvis, several vertebrae, and a few ribs collected by Fielding Bradford Meek and Henry Martyn Bannister near the Green River of southeastern Wyoming from layers coming from the Maastrichtian Lance Formation . Due to the fragmentary nature of the remains, it can only confidently be assigned to Ceratopsidae. Polyonax mortuarius was collected by Cope himself in 1873 from northeastern Colorado, possibly coming from

6972-478: Was short with four functional toes. The phalangeal formula of the foot is 2-3-4-5-0. Although certainly quadrupedal , the posture of horned dinosaurs has long been the subject of some debate. Originally, it was believed that the front legs of the animal had to be sprawling at a considerable angle from the thorax in order to better bear the weight of the head. This stance can be seen in paintings by Charles Knight and Rudolph Zallinger . Ichnological evidence in

7056-416: Was very large and sported a neural spine. Later interpretations revived an old hypothesis by John Bell Hatcher that, at the very front, a vestige of the real atlas can be observed, the syncervical then consisting of four vertebrae. The vertebral count mentioned is adjusted to this view. In Triceratops , the neural spines of the neck are constant in height and don't gradually slope upwards. Another peculiarity

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