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107-627: Daspletosaurus ( / d æ s ˌ p l iː t ə ˈ s ɔːr ə s / das- PLEET -ə- SOR -əs ; meaning "frightful lizard") is a genus of tyrannosaurid dinosaur that lived in Laramidia between about 78 and 74.4 million years ago, during the Late Cretaceous Period . The genus Daspletosaurus contains three named species . Fossils of the earlier type species , D. torosus , have been found in Alberta , while fossils of

214-517: A calendar year , but the word is also used for periods loosely associated with the calendar or astronomical year, such as the seasonal year , the fiscal year , the academic year , etc. The term can also be used in reference to any long period or cycle, such as the Great Year . Due to the Earth's axial tilt , the course of a year sees the passing of the seasons , marked by changes in weather ,

321-557: 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 ,

428-507: A Two Medicine bonebed by Currie et al. (2005); the authors stated that this fossil material likely represents then-unnamed species mentioned by Horner et al. (1992), but cautioned that further study and description of Daspletosaurus would be necessary before the species can be determined with certainty. In 2017, the Two Medicine Formation taxon was named as the new species D. horneri . Isolated tyrannosaurid teeth in

535-498: A distinct species yet to be named, referred to as D. sp. In the lower portion of the Judith River Formation, around 78 million years ago, there is some evidence for a new undescribed tyrannosaurid taxon. A specimen in the collections of Triebold Paleontology excavated between 2002 and 2004, known as "Sir William" (RMDRC 2002.MT-001), shows some characteristics of Daspletosaurus suggesting a new earlier species to

642-449: A fixed frame of reference (such as the fixed stars, Latin sidera , singular sidus ). Its average duration is 365.256 363 004 days (365 d 6 h 9 min 9.76 s) (at the epoch J2000.0 = January 1, 2000, 12:00:00 TT ). Today the mean tropical year is defined as the period of time for the mean ecliptic longitude of the Sun to increase by 360 degrees. Since the Sun's ecliptic longitude

749-459: A junior synonym of D. torosus . In the same year, however, Warshaw and colleagues supported the validity of this species and referred other specimens to it. While very large by the standard of modern predators, Daspletosaurus was not the largest tyrannosaurid. Adults could reach a length of 8.5–9 metres (28–30 ft) from snout to tail, a hip height of 2.2 metres (7.2 ft), and a body mass of 2–3 metric tons (2.2–3.3 short tons). However there

856-651: 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

963-532: A later species, D. horneri , have been found only in Montana . D. wilsoni has been suggested as an intermediate species between D. torosus and D. horneri that evolved through anagenesis , but this theory has been disputed by other researchers. There are also multiple specimens which may represent new species of Daspletosaurus from Alberta and Montana, but these have not been formally described. The taxon Thanatotheristes has been suggested to represent

1070-626: A leap year there are 366 days. A leap year occurs every fourth year during which a leap day is intercalated into the month of February. The name "Leap Day" is applied to the added day. In astronomy, the Julian year is a unit of time defined as 365.25 days, each of exactly 86,400 seconds ( SI base unit ), totaling exactly 31,557,600 seconds in the Julian astronomical year. The Revised Julian calendar , proposed in 1923 and used in some Eastern Orthodox Churches , has 218 leap years every 900 years, for

1177-628: 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,

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1284-435: A person carrying a bundle of wheat denoting "harvest". Slavic besides godŭ "time period; year" uses lěto "summer; year". Astronomical years do not have an integer number of days or lunar months. Any calendar that follows an astronomical year must have a system of intercalation such as leap years. In the Julian calendar , the average (mean) length of a year is 365.25 days. In a non-leap year, there are 365 days, in

1391-710: A reference event in the past (called the epoch ) as the beginning of the era. The Gregorian calendar era is the world's most widely used civil calendar . Its epoch is a 6th century estimate of the date of birth of Jesus of Nazareth . Two notations are used to indicate year numbering in the Gregorian calendar: the Christian " Anno Domini " (meaning "in the year of the Lord"), abbreviated AD; and " Common Era ", abbreviated CE, preferred by many of other faiths and none. Year numbers are based on inclusive counting , so that there

1498-409: 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

1605-416: A short, S-shaped neck supporting the massive skull. It walked on its two thick hindlimbs, which ended in four-toed feet, although the first digit (the hallux ) did not contact the ground. In contrast, the forelimbs were extremely small and bore only two digits , although Daspletosaurus had the longest forelimbs in proportion to body size of any tyrannosaurid. A long, heavy tail served as a counterweight to

1712-534: A species of Daspletosaurus , D. degrootorum , but this has not been widely supported. Daspletosaurus is closely related to the much larger and more recent tyrannosaurid Tyrannosaurus rex . Like most tyrannosaurids, Daspletosaurus was a large bipedal predator , with the average adult measuring 8.5–9 m (28–30 ft) and weighing 3 metric tons (3.3 short tons). However, the largest potential specimen measures around 11 metres (36 ft) long and weighs up to 5 metric tons (5.5 short tons). Daspletosaurus had

1819-427: 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. ;

1926-565: A time interval in Julian years is a way to precisely specify an amount of time (not how many "real" years), for long time intervals where stating the number of ephemeris days would be unwieldy and unintuitive. By convention, the Julian year is used in the computation of the distance covered by a light-year . In the Unified Code for Units of Measure (but not according to the International Union of Pure and Applied Physics or

2033-455: 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

2140-495: Is 365.2425 days (97 out of 400 years are leap years). In English, the unit of time for year is commonly abbreviated as "y" or "yr". The symbol "a" (for Latin : annus , year) is sometimes used in scientific literature, though its exact duration may be inconsistent. English year (via West Saxon ġēar ( /jɛar/ ), Anglian ġēr ) continues Proto-Germanic *jǣran ( *j ē₁ ran ). Cognates are German Jahr , Old High German jār , Old Norse ár and Gothic jer , from

2247-765: Is a 12-month period used for calculating annual financial statements in businesses and other organizations. In many jurisdictions, regulations regarding accounting require such reports once per twelve months, but do not require that the twelve months constitute a calendar year. For example, in Canada and India the fiscal year runs from April 1; in the United Kingdom it runs from April 1 for purposes of corporation tax and government financial statements, but from April 6 for purposes of personal taxation and payment of state benefits; in Australia it runs from July 1; while in

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2354-850: Is a cladogram of Tyrannosaurinae based on the phylogenetic analysis conducted by Warshaw & Fowler (2022). Here, it is proposed that the three Daspletosaurus species evolved through anagenesis in the Tyrannosaurinae in a line leading to Zhuchengtyrannus , Tarbosaurus , and Tyrannosaurus . Due to their more fragmentary nature, Thanatotheristes and Nanuqsaurus were excluded from this analysis. Alioramus remotus [REDACTED] Alioramus altai [REDACTED] Qianzhousaurus [REDACTED] Dynamoterror Teratophoneus [REDACTED] Lythronax [REDACTED] Daspletosaurus wilsoni Daspletosaurus horneri Zhuchengtyrannus Tarbosaurus [REDACTED] In 2024, Scherer and Voiculescu-Holvad argued that

2461-442: Is about 20 minutes shorter than the sidereal year. The mean tropical year is approximately 365 days, 5 hours, 48 minutes, 45 seconds, using the modern definition ( = 365.24219 d × 86 400 s). The length of the tropical year varies a bit over thousands of years because the rate of axial precession is not constant. The anomalistic year is the time taken for the Earth to complete one revolution with respect to its apsides . The orbit of

2568-408: Is an approximation of the number of days of the Earth's orbital period, as counted in a given calendar . The Gregorian calendar , or modern calendar, presents its calendar year to be either a common year of 365 days or a leap year of 366 days, as do the Julian calendars . For the Gregorian calendar, the average length of the calendar year (the mean year) across the complete leap cycle of 400 years

2675-534: Is an integral approximation to the year equaling 365 days, which wanders in relation to more exact years. Typically the vague year is divided into 12 schematic months of 30 days each plus 5 epagomenal days. The vague year was used in the calendars of Ethiopia , Ancient Egypt , Iran , Armenia and in Mesoamerica among the Aztecs and Maya . It is still used by many Zoroastrian communities. A heliacal year

2782-612: 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

2889-427: Is measured with respect to the equinox, the tropical year comprises a complete cycle of the seasons and is the basis of solar calendars such as the internationally used Gregorian calendar . The modern definition of mean tropical year differs from the actual time between passages of, e.g., the northward equinox, by a minute or two, for several reasons explained below. Because of the Earth's axial precession , this year

2996-637: Is named after the 19th-century German astronomer and mathematician Friedrich Bessel . The following equation can be used to compute the current Besselian epoch (in years): The TT subscript indicates that for this formula, the Julian date should use the Terrestrial Time scale, or its predecessor, ephemeris time . The exact length of an astronomical year changes over time. Numerical value of year variation Mean year lengths in this section are calculated for 2000, and differences in year lengths, compared to 2000, are given for past and future years. In

3103-471: Is no "year zero". Years before the epoch are abbreviated BC for Before Christ or BCE for Before the Common Era . In Astronomical year numbering , positive numbers indicate years AD/CE, the number 0 designates 1 BC/BCE, −1 designates 2 BC/BCE, and so on. Other eras include that of Ancient Rome , Ab Urbe Condita ("from the foundation of the city ), abbreviated AUC; Anno Mundi ("year of

3210-670: Is no stratigraphic overlap between D. torosus and D. wilsoni , since a large specimen (CMC VP 15826) previously referred to as D. torosus is from a strata recently dated to be later than D. wilsoni , and since this specimen likely belongs to a distinct species of Daspletosaurus yet to be named. They also recovered the paraphyletic Daspletosaurus at the base of Tyrannosaurini, making the genus ancestral to Tyrannosaurus . There are indications of D. horneri possessing integumentary sensory organs, possibly used in touch, modulation of precise jaw movements, temperature reading, and prey detection. The large flat scales may have further protected

3317-413: Is one potential specimen of D. torosus or a new unnamed species, CMC VP 15826 (nicknamed "Pete III"), that suggests the genus could reach lengths of nearly 11 metres (36 ft) and weigh 5 metric tons (5.5 short tons). Daspletosaurus had a massive skull that could reach more than 1 metre (3 ft 3 in) in length. The bones were heavily constructed and some, including the nasal bones on top of

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3424-403: Is some evidence of niche differentiation between the two. While Daspletosaurus fossils are not as common as other tyrannosaurid fossils, the available specimens allow some analysis of the biology of these animals, including social behavior , diet, and life history. The type specimen of Daspletosaurus torosus ( CMN 8506) is a partial skeleton including the skull, the shoulder, a forelimb,

3531-460: 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,

3638-815: Is the accusative singular ; annī is genitive singular and nominative plural; annō the dative and ablative singular) is from a PIE noun *h₂et-no- , which also yielded Gothic aþn "year" (only the dative plural aþnam is attested). Although most languages treat the word as thematic *yeh₁r-o- , there is evidence for an original derivation with an *-r/n suffix, *yeh₁-ro- . Both Indo-European words for year, *yeh₁-ro- and *h₂et-no- , would then be derived from verbal roots meaning "to go, move", *h₁ey- and *h₂et- , respectively (compare Vedic Sanskrit éti "goes", atasi "thou goest, wanderest"). A number of English words are derived from Latin annus , such as annual , annuity , anniversary , etc.; per annum means "each year", annō Dominī means "in

3745-474: 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

3852-413: Is the interval between the heliacal risings of a star. It differs from the sidereal year for stars away from the ecliptic due mainly to the precession of the equinoxes . The Sothic year is the heliacal year, the interval between heliacal risings, of the star Sirius . It is currently less than the sidereal year and its duration is very close to the Julian year of 365.25 days. The Gaussian year

3959-534: Is the sidereal year for a planet of negligible mass (relative to the Sun) and unperturbed by other planets that is governed by the Gaussian gravitational constant . Such a planet would be slightly closer to the Sun than Earth's mean distance. Its length is: The Besselian year is a tropical year that starts when the (fictitious) mean Sun reaches an ecliptic longitude of 280°. This is currently on or close to January 1. It

4066-539: Is the time taken for the Sun (as seen from the Earth) to complete one revolution with respect to the same lunar node (a point where the Moon's orbit intersects the ecliptic). The year is associated with eclipses : these occur only when both the Sun and the Moon are near these nodes; so eclipses occur within about a month of every half eclipse year. Hence there are two eclipse seasons every eclipse year. The average duration of

4173-695: The Dinosaur Park Formation in Alberta. The Dinosaur Park Formation was formerly known as the Upper Oldman Formation and dates back to the middle Campanian, between 76.5 and 74.8  million years ago . Daspletosaurus fossils are known specifically from the middle to upper section of the formation, between 75.6 and 75.0 million years ago. In 1914, Brown collected a nearly complete skeleton and skull; forty years later his American Museum of Natural History sold this specimen to

4280-568: The Field Museum of Natural History in Chicago . It was mounted for display in Chicago and labeled as Albertosaurus libratus for many years, but after several skull features were later found to be modeled in plaster, including most of the teeth, the specimen ( FMNH PR308) was reassigned to Daspletosaurus torosus by Thomas Carr in 1999. A total of eight specimens have been collected from

4387-488: The Greek δασπλής ( dasplēs , stem and connective vowel resulting in dasplēto -) ("frightful") and σαυρος ( sauros ) ("lizard"). The type species is Daspletosaurus torosus , the specific name torosus being Latin for 'muscular' or 'brawny'. Aside from the type, there is only one other well-known specimen, RTMP 2001.36.1, a relatively complete skeleton discovered in 2001. Both specimens were recovered from

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4494-621: 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

4601-824: 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;

4708-444: The International Union of Geological Sciences , see below), the symbol a (without subscript) always refers to the Julian year, a j , of exactly 31 557 600 seconds . The SI multiplier prefixes may be applied to it to form "ka", "Ma", etc. Each of these three years can be loosely called an astronomical year . The sidereal year is the time taken for the Earth to complete one revolution of its orbit , as measured against

4815-644: The Oldman Formation in the Judith River Group of Alberta. The Oldman Formation was deposited during the middle Campanian stage of the Late Cretaceous , from about 79.5 to 77 Ma (million years ago). Dale Russell also suggested that a specimen of an immature Albertosaurus (CMN 11315) from the younger Horseshoe Canyon Formation in Alberta actually belonged to a third specimen of Daspletosaurus as D. cf. torosus , extending

4922-472: The Proto-Indo-European noun *yeh₁r-om "year, season". Cognates also descended from the same Proto-Indo-European noun (with variation in suffix ablaut ) are Avestan yārǝ "year", Greek ὥρα ( hṓra ) "year, season, period of time" (whence " hour "), Old Church Slavonic jarŭ , and Latin hornus "of this year". Latin annus (a 2nd declension masculine noun; annum

5029-607: The United States the fiscal year of the federal government runs from October 1. An academic year is the annual period during which a student attends an educational institution . The academic year may be divided into academic terms , such as semesters or quarters. The school year in many countries starts in August or September and ends in May, June or July. In Israel the academic year begins around October or November, aligned with

5136-400: The pelvis , a femur, and all of the vertebrae from the neck, torso, and hip, as well as the first eleven tail vertebrae. It was discovered in 1921 near Steveville, Alberta , by Charles Mortram Sternberg , who thought it was a new species of Gorgosaurus . It was not until 1970 that the specimen was fully described by Dale Russell , who made it the type of a new genus, Daspletosaurus , from

5243-409: The perigee of the Moon's orbit. This period is associated with the apparent size of the full moon , and also with the varying duration of the synodic month . The duration of one full moon cycle is: The lunar year comprises twelve full cycles of the phases of the Moon, as seen from Earth. It has a duration of approximately 354.37 days. Muslims use this for celebrating their Eids and for marking

5350-404: 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,

5457-570: The 2023 meeting of the Society of Vertebrate Paleontology , Thomas Carr and Stephen Brusatte presented evidence questioning the validity of D. wilsoni. They said the autapomorphy (unique feature) of D. wilsoni was incorrectly determined, rendering the species a nomen dubium , but they found BDM 107 actually shared traits with D. torosus but not with D. horneri, prompting them to synonymize D. wilsoni with D. torosus . In 2024, Scherer and Voiculescu-Holvad also suggested that D. wilsoni may be

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5564-556: The Dinosaur Park Formation over the years since, most of them within the boundaries of Dinosaur Provincial Park . Phil Currie believes that the Dinosaur Park specimens represent a new species of Daspletosaurus , distinguished by certain features of the skull. Pictures of this new species have been published, but it still awaits a name and full description in print. In 2024, Warshaw and colleagues suggested that

5671-466: The Dinosaur Park specimens likely belong to D. wilsoni . A new tyrannosaurid specimen ( OMNH 10131), including skull fragments, ribs, and parts of the hindlimb, was reported from New Mexico in 1990 and assigned to the now-defunct genus Aublysodon . Many later authors have reassigned this specimen, along with a few others from New Mexico, to yet another unnamed species of Daspletosaurus . However, research published in 2010 showed that this species, from

5778-424: The Earth is elliptical; the extreme points, called apsides, are the perihelion , where the Earth is closest to the Sun, and the aphelion , where the Earth is farthest from the Sun. The anomalistic year is usually defined as the time between perihelion passages. Its average duration is 365.259636 days (365 d 6 h 13 min 52.6 s) (at the epoch J2011.0). The draconic year, draconitic year, eclipse year, or ecliptic year

5885-473: 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

5992-681: The Hunter Wash Member of the Kirtland Formation , is actually a more primitive tyrannosauroid, and was classified in the genus Bistahieversor . In 1992, Jack Horner and colleagues published an extremely preliminary report of a tyrannosaurid from the upper parts of the Campanian Two Medicine Formation in Montana, which was interpreted as a transitional species between Daspletosaurus and

6099-462: The Judith River Formation. Elías A. Warshaw and Denver W. Fowler described these remains ( BDM 107) in 2022 as belonging to a new species of Daspletosaurus , D. wilsoni . It represents a transitional species between D. torosus and D. horneri , as it existed between them in time. It has been suggested that the three species may have evolved directly through anagenesis , but this theory was disputed by Scherer and Voiculescu-Holvad in 2024. However, at

6206-725: The United Kingdom, and 200 for pupils in Australia. In India the academic year normally starts from June 1 and ends on May 31. Though schools start closing from mid-March, the actual academic closure is on May 31 and in Nepal it starts from July 15. Schools and universities in Australia typically have academic years that roughly align with the calendar year (i.e., starting in February or March and ending in October to December), as

6313-637: The United States, notably Boston Latin School , may divide the year into five or more marking periods. Some state in defense of this that there is perhaps a positive correlation between report frequency and academic achievement. There are typically 180 days of teaching each year in schools in the US, excluding weekends and breaks, while there are 190 days for pupils in state schools in Canada, New Zealand and

6420-468: The animal survived the bite. Evidence that Daspletosaurus lived in social groups comes from a bonebed found in the Two Medicine Formation of Montana. The bonebed includes the remains of three Daspletosaurus , including a large adult, a small juvenile, and another individual of intermediate size. At least five hadrosaurs are preserved at the same location. Geologic evidence indicates that the remains were not brought together by river currents but that all of

6527-467: The animals were buried simultaneously at the same location. The hadrosaur remains are scattered and bear numerous marks from tyrannosaur teeth, indicating that the Daspletosaurus were feeding on the hadrosaurs at the time of death. The cause of death is unknown. Currie speculates that the daspletosaurs formed a pack , although this cannot be stated with certainty. Other scientists are skeptical of

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6634-477: The average (mean) year length of 365.242 2222 days, close to the length of the mean tropical year, 365.242 19 days (relative error of 9·10). In the year 2800 CE, the Gregorian and Revised Julian calendars will begin to differ by one calendar day. The Gregorian calendar aims to ensure that the northward equinox falls on or shortly before March 21 and hence it follows the northward equinox year , or tropical year . Because 97 out of 400 years are leap years,

6741-442: 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

6848-682: The basis of morphological and stratigraphical data, and that anagenesis will not be supported unequivocally due to the limited sample and nature of the fossil record, which does not show a great degree of variation in morphology. The cladogram presented for their phylogenetic analysis is shown below. Alioramus remotus [REDACTED] Alioramus altai Qianzhousaurus [REDACTED] Lythronax [REDACTED] Teratophoneus Dynamoterror Thanatotheristes Daspletosaurus horneri Daspletosaurus wilsoni Dinosaur Park and Oldman formations taxon ( TMP 2001.36.1) Zhuchengtyrannus Tarbosaurus [REDACTED] In

6955-495: The bites are due to intraspecific competition for territory or resources, or for dominance within a social group. A young specimen of the tyrannosaurid (TMP 1994.143.1), initially identified as the Dinosaur Park Daspletosaurus but subsequently referred to Gorgosaurus libratus , also shows bite marks on the face that were inflicted by another tyrannosaur. The bite marks are healed over, indicating that

7062-479: The diagnostic skeletal traits used to identify mature tyrannosaurids. An additional maxilla and various teeth from an Edmontosaurus -dominated bonebed in the Horseshoe Canyon Formation was also mistakenly referred to Daspletosaurus , but all the tyrannosaurid material has all since been confirmed to belong to Albertosaurus . Over the years, various additional species have been assigned to

7169-407: The eclipse year is This term is sometimes erroneously used for the draconic or nodal period of lunar precession , that is the period of a complete revolution of the Moon's ascending node around the ecliptic: 18.612 815 932 Julian years ( 6 798 .331 019 days; at the epoch J2000.0). The full moon cycle is the time for the Sun (as seen from the Earth) to complete one revolution with respect to

7276-544: The evidence for social groups in Daspletosaurus and other large theropods; Brian Roach and Daniel Brinkman have suggested that Daspletosaurus social interaction would have more closely resembled the modern Komodo dragon , where non-cooperative individuals mob carcasses, frequently attacking and even cannibalizing each other in the process. Fossils of other tyrannosaurids like Teratophoneus and Albertosaurus among other genera suggest that gregarious behavior may have been widespread in tyrannosaurs and thus may vindicate

7383-446: 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

7490-737: 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,

7597-410: The genus Daspletosaurus . Though some have been designated as Daspletosaurus spp, this does not imply that they all represent the same species. Along with the holotype , Russell designated a specimen collected by Barnum Brown in 1913 as the paratype of D. torosus . This specimen ( AMNH 5438) consists of parts of the hindleg, the pelvis, and some of its associated vertebrae. It was discovered in

7704-422: The genus. However, the specimen shows many characteristics typical of early tyrannosaurines such as Teratophoneus and even some of the later Tyrannosaurus , which may suggest an entirely new genus. In 2017, John Wilson discovered the bones of a tyrannosaurid, including a partial disarticulated skull, cervical, sacral, and caudal vertebrae, and a rib, chevron, and first metatarsal, from the "Jack’s B2" site of

7811-574: The head and torso, with the center of gravity over the hips. From a comparison of the degree of wear of teeth of Daspletosaurus with other extinct and extant animals, it is concluded that Daspletosaurus , as well as other non-avian theropods, had lips that protected the teeth from external influences. Due to this feature, the snout of Daspletosaurus more closely resembled lizards than crocodiles, which lack lips. A skin impression from Daspletosaurus torosus has been described, showing small polygonal scales measuring 3 mm in diameter. The placement of

7918-491: The historical Jalali calendar , known as the Solar Hijri calendar (1925), is a purely solar calendar with an irregular pattern of leap days based on observation (or astronomical computation), aiming to place new year ( Nowruz ) on the day of vernal equinox (for the time zone of Tehran ), as opposed to using an algorithmic system of leap years. A calendar era assigns a cardinal number to each sequential year, using

8025-433: The hours of daylight , and, consequently, vegetation and soil fertility . In temperate and subpolar regions around the planet, four seasons are generally recognized: spring , summer , autumn , and winter . In tropical and subtropical regions, several geographical sectors do not present defined seasons; but in the seasonal tropics , the annual wet and dry seasons are recognized and tracked. A calendar year

8132-552: The hypothesis of Daspletosaurus being a social animal, as bonebeds of these genera containing multiple specimens in a wide range of ages have been excavated and described from these different genera. Evidence of cannibalism in Daspletosaurus was published in 2015. 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

8239-432: 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

8346-633: 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,

8453-571: The later Tyrannosaurus . Currie (2003) stated that the tyrannosaurid from the Two Medicine Formation mentioned by Horner et al. (1992) may be an unnamed third species of Daspletosaurus . Another partial skeleton was reported from the Upper Two Medicine in 2001, preserving the remains of a juvenile hadrosaur in its abdominal cavity . This specimen was assigned to Daspletosaurus but not to any particular species. The remains of at least three more Daspletosaurus have also been described in

8560-448: 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. Mega-annum A year is the time taken for astronomical objects to complete one orbit . For example, a year on Earth is the time taken for Earth to revolve around the Sun . Generally, a year is taken to mean

8667-543: The mean length of the Gregorian calendar year is 365.242 5 days; with a relative error below one ppm (8·10) relative to the current length of the mean tropical year ( 365.242 189 days) and even closer to the current March equinox year of 365.242 374 days that it aims to match. Historically, lunisolar calendars intercalated entire leap months on an observational basis. Lunisolar calendars have mostly fallen out of use except for liturgical reasons ( Hebrew calendar , various Hindu calendars ). A modern adaptation of

8774-403: 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

8881-539: The most basal species, in spite of being the youngest species stratigraphically. While the authors did not completely refute the possibility that anagenesis was the main driver of Daspletosaurus evolution based on the intermediate morphological features, they also suggested that D. wilsoni may be a junior synonym of D. torosus , since there is a near lack of autapomorphic characters that can differentiate this species. They also claimed that Daspletosaurus did not evolve from Thanatotheristes , since they found no support on

8988-428: 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

9095-601: The other subfamily, the Albertosaurinae. It further belongs to the tribe Daspletosaurini, consisting of it and the taxon Thanatotheristes . Daspletosaurus is usually considered to be closely related to Tyrannosaurus rex , or even a direct ancestor through anagenesis . Gregory Paul reassigned D. torosus to the genus Tyrannosaurus , creating the new combination Tyrannosaurus torosus , but this has not been generally accepted. Many researchers believe Tarbosaurus and Tyrannosaurus to be sister taxa or even to be

9202-541: 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

9309-499: The rough outer surface of the maxilla (upper jaw bone) and the pronounced crests around the eyes on the lacrimal , postorbital , and jugal bones. The orbit (eye socket) was a tall oval, somewhere in between the circular shape seen in Gorgosaurus and the 'keyhole' shape of Tyrannosaurus . Split carinae (edges) have been found on Daspletosaurus teeth. Daspletosaurus shared the same body form as other tyrannosaurids, with

9416-486: The same genus, with Daspletosaurus a more basal relative. On the other hand, Phil Currie and colleagues find Daspletosaurus to be more closely related to Tarbosaurus and other Asian tyrannosaurids like Alioramus than to the North American Tyrannosaurus . The systematics ( evolutionary relationships) of Daspletosaurus have become clearer as new species have been described. Below

9523-461: The same year, Warshaw and colleagues supported the anagenesis theory by referring other specimens to D. wilsoni (including the Dinosaur Park specimen) which they considered as a valid taxon, and by reanalysing the previous study of Scherer and Voiculescu-Holvad (2024). They claimed that the known species of Daspletosaurus show a gradient of morphologies consistent with them representing a series of ancestors and descendants. They also argued that there

9630-441: The scales on the body is not known. Daspletosaurus belongs in the subfamily Tyrannosaurinae within the family Tyrannosauridae , along with Tarbosaurus , Tyrannosaurus , and Alioramini . Animals in this subfamily are more closely related to Tyrannosaurus than to Albertosaurus and are known – with the exception of Alioramus  – for their robust build with proportionally larger skulls and longer femora than in

9737-605: The second month of the Hebrew calendar. Some schools in the UK, Canada and the United States divide the academic year into three roughly equal-length terms (called trimesters or quarters in the United States), roughly coinciding with autumn, winter, and spring. At some, a shortened summer session, sometimes considered part of the regular academic year, is attended by students on a voluntary or elective basis. Other schools break

9844-445: The small forelimbs typical of tyrannosaurids, although they were proportionately longer than in other genera. As an apex predator equipped with dozens of large, sharp teeth, Daspletosaurus was at the top of the food chain , probably preying on large dinosaurs like the ceratopsid Centrosaurus and the hadrosaur Hypacrosaurus . In some areas, Daspletosaurus coexisted with another tyrannosaurid, Gorgosaurus , though there

9951-529: The snout during prey capture and intra-specific combat. A full-grown Dinosaur Park Daspletosaurus ( TMP 85.62.1) exhibits tyrannosaur bite marks on its skull. While it is possible that the bites were attributable to other species, intraspecific aggression such as facial biting is very common among predators. Facial bites are seen in other tyrannosaurs like Gorgosaurus and Tyrannosaurus , as well as in other theropod genera like Sinraptor and Saurornitholestes . Darren Tanke and Phil Currie hypothesize that

10058-430: The snout, were fused for strength. Large fenestrae (openings) in the skull reduced its weight. An adult Daspletosaurus was armed with about six dozen teeth that were very long but oval in cross section rather than blade-like. Unlike its other teeth, those in the premaxilla at the end of the upper jaw had a D-shaped cross section, an example of heterodonty always seen in tyrannosaurids. Unique skull features included

10165-475: The southern hemisphere experiences summer from December to February. The Julian year, as used in astronomy and other sciences, is a time unit defined as exactly 365.25 days of 86,400 SI seconds each (" ephemeris days "). This is the normal meaning of the unit "year" used in various scientific contexts. The Julian century of 36 525 ephemeris days and the Julian millennium of 365 250 ephemeris days are used in astronomical calculations. Fundamentally, expressing

10272-497: 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,

10379-412: 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

10486-512: The start of the fasting month of Ramadan . A Muslim calendar year is based on the lunar cycle. The Jewish calendar is also essentially lunar, except that an intercalary lunar month is added once every two or three years, in order to keep the calendar synchronized with the solar cycle as well. Thus, a lunar year on the Jewish (Hebrew) calendar consists of either twelve or thirteen lunar months. The vague year, from annus vagus or wandering year,

10593-408: The stratigraphic ranges of D. torosus , D. wilsoni and an unnamed species from the Dinosaur Park Formation and Oldman Formation show a clear overlap, indicating that anagenesis may not be the predominant factor of speciation within the genus, since all species of Daspletosaurus were contemporaneous with each other at some point during its evolution. Phylogenetic analyzes resolved D. horneri as

10700-403: 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

10807-499: The temporal range of the genus by approximately 3.5 million years into the Maastrichtian . He based this referral on features of its limb and pelvic girdle, as well as the curvature of the hand claws, which he interpreted as traits matching Daspletosaurus . This reassignment was not universally accepted, and thorough re-examination of the specimen favored its initial referral to Albertosaurus sarcophagus , despite lacking many of

10914-561: The upper portions of the Judith River Formation are likely from Gorgosaurus as well as some species of Daspletosaurus , probably D. torosus . In 2009, preliminary preparation of a Daspletosaurus specimen from the Coal Ridge Member of the Judith River Formation measuring about 11 metres (36 ft) long was reported. Some researchers assigned this specimen to D. torosus , while others considered it to be

11021-576: 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

11128-429: 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

11235-560: The world"), used for the Hebrew calendar and abbreviated AM; and the Japanese imperial eras . The Islamic Hijri year , (year of the Hijrah , Anno Hegirae abbreviated AH), is a lunar calendar of twelve lunar months and thus is shorter than a solar year. Financial and scientific calculations often use a 365-day calendar to simplify daily rates. A fiscal year or financial year

11342-454: The year into two main semesters, a first (typically August through December) and a second semester (January through May). Each of these main semesters may be split in half by mid-term exams, and each of the halves is referred to as a quarter (or term in some countries). There may also be a voluntary summer session or a short January session. Some other schools, including some in the United States, have four marking periods. Some schools in

11449-732: The year of the Lord". The Greek word for "year", ἔτος , is cognate with Latin vetus "old", from the PIE word *wetos- "year", also preserved in this meaning in Sanskrit vat-sa-ras "year" and vat-sa- "yearling (calf)", the latter also reflected in Latin vitulus "bull calf", English wether "ram" (Old English weðer , Gothic wiþrus "lamb"). In some languages, it is common to count years by referencing to one season, as in "summers", or "winters", or "harvests". Examples include Chinese 年 "year", originally 秂 , an ideographic compound of

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