Genus ( / ˈ dʒ iː n ə s / ; pl. : genera / ˈ dʒ ɛ n ər ə / ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses . In binomial nomenclature , the genus name forms the first part of the binomial species name for each species within the genus.
122-504: Albertosaurus ( / æ l ˌ b ɜːr t ə ˈ s ɔːr ə s / ; meaning "Alberta lizard") is a genus of large tyrannosaurid theropod dinosaur that lived in northwestern North America during the early to middle Maastrichtian age of the Late Cretaceous period, about 71 million years ago . The type species , A. sarcophagus , was apparently restricted in range to the modern-day Canadian province of Alberta , after which
244-421: A nomen dubium that could only be used for the type specimen itself because other fossils could not reliably be assigned to it. However, in 2010, Thomas Carr established that the holotype, the paratype, and comparable later finds all shared a single common unique trait, or autapomorphy . The possession of an enlarged pneumatic opening in the back rim of the side of the palatine bone proves that Albertosaurus
366-415: A drill to create an "ampulla" of sorts and prevent the propagation of cracks through material is also used to protect aircraft surfaces. Abler demonstrated that a plexiglass bar with incisions called "kerfs" and drilled holes was more than 25% stronger than one with only regularly placed incisions. Unlike tyrannosaurs, more ancient predators, like phytosaurs and Dimetrodon , had no adaptations to prevent
488-525: A megalosaurid . Marsh, however, examined the remains and later assigned to its own monotypic family, Dryptosauridae. The fossil material assigned to Dryptosaurus was reviewed by Ken Carpenter in 1997, in light of the many different theropods discovered since Cope's time. He felt that due to some unusual features it couldn't be placed in any existing family and, like Marsh, he felt that it warranted placement in Dryptosauridae. This phylogenetic assignment
610-557: 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 ,
732-456: A basal eotyrannosaurian just outside of Tyrannosauridae, in agreement with other authors. The other major subfamily of tyrannosaurids is Tyrannosaurinae, which includes members like Daspletosaurus , Tarbosaurus , and Tyrannosaurus . Compared with the more robust tyrannosaurines, albertosaurines had slender builds, with proportionately smaller skulls and longer bones of the lower legs ( tibia ) and feet ( metatarsals and phalanges ). Below
854-535: A body, so when a tyrannosaur pulled back on a piece of meat, the tension could cause a purely crack-like serration to spread through the tooth. However, the presence of the ampulla distributed these forces over a larger surface area and lessened the risk of damage to the tooth under strain. The presence of incisions ending in voids has parallels in human engineering. Guitar makers use incisions ending in voids to, as Abler describes, "impart alternating regions of flexibility and rigidity" to wood that they work on. The use of
976-489: A flat shaft proximally (resulting in a semiovoid cross section that is much wider mediolaterally than it is long anteroposteriorly). Since the time of its discovery, Dryptosaurus has been classified in a number of different theropod families. Cope (1866), Leidy (1868), and Lydekker (1888) noted obvious similarities with the genus Megalosaurus , which was known at the time from remains discovered in southeastern England . Based on this line of reasoning, Cope classified it as
1098-453: A fragmentary right ischium , the left femur , the left tibia , the left fibula , the left astragalus , and a midshaft fragment of metatarsal III. The ontological maturity of the holotype individual is supported by the fact that the neurocentral sutures are closed in all of its caudal vertebrae. AMNH FARB 2438 consists of left metatarsal IV, which are likely from the same individual as the holotype. The fragmentary right maxilla preserves
1220-614: A juvenile Tyrannosaurus rex . Also in 1988, Paul renamed Alectrosaurus olseni (Gilmore 1933) into Albertosaurus olseni , but this has found no general acceptance. In 1989, Gorgosaurus novojilovi (Maleev 1955) was renamed by Bryn Mader and Robert Bradley as Albertosaurus novojilovi . On two occasions, species based on valid Albertosaurus material were reassigned to a different genus, Deinodon . In 1922, William Diller Matthew renamed A. sarcophagus into Deinodon sarcophagus . In 1939, German paleontologist Oskar Kuhn renamed A. arctunguis into Deinodon arctunguis . Albertosaurus
1342-451: A large role, especially since more than two-thirds of all Albertosaurus specimens are known from the exact same locality. The Dry Island bonebed discovered by Barnum Brown and his crew contains the remains of 26 Albertosaurus , the most individuals found in one locality of any large Cretaceous theropod and the second-most of any large theropod dinosaur behind the Allosaurus assemblage at
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#17328844174491464-643: 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
1586-468: A location nearby. The two skulls were assigned to the preexisting species Laelaps incrassatus by Edward Drinker Cope in 1892. Although the name Laelaps was preoccupied by a genus of mite and had been changed to Dryptosaurus in 1877 by Othniel Charles Marsh , Cope stubbornly refused to recognize the new name created by his archrival. However, Lawrence Lambe used the name Dryptosaurus incrassatus instead of Laelaps incrassatus when he described
1708-621: 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,
1830-475: A puncture wound and both healed and unhealed bite marks. The low number of abnormalities compares favourably with the health condition of a Majungasaurus population of which it was established, in 2007, that 19% of individuals showed bone pathologies. Most fossils of Albertosaurus sarcophagus are known from the upper Horseshoe Canyon Formation in Alberta. These younger units of this geologic formation date to
1952-409: 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
2074-462: A slowly rising water level during an extended flood. In 2009, researchers hypothesized that smooth-edged holes found in the fossil jaws of tyrannosaurid dinosaurs, such as Albertosaurus , were caused by a parasite similar to Trichomonas gallinae , which infects birds. They suggested that tyrannosaurids transmitted the infection by biting each other and that the infection impaired their ability to eat. In 2001, Bruce Rothschild and others published
2196-413: A strong sense of smell, powerful binocular vision, and a bone crushing bite force. It may have even been the apex predator in its local ecosystem . While Albertosaurus was certainly large for a theropod, it was still much smaller than its larger and more famous relative Tyrannosaurus rex , growing up to 8–9 metres (26–30 ft) in length and weighing 1.7–3.0 metric tons (1.9–3.3 short tons). Since
2318-483: A study examining evidence for stress fractures and tendon avulsions in theropod dinosaurs and the implications for their behavior. They found that only one of the 319 Albertosaurus foot bones checked for stress fractures actually had them and none of the four hand bones did. The scientists found that stress fractures were "significantly" less common in Albertosaurus than in the carnosaur Allosaurus . ROM 807,
2440-415: A sudden increase in mortality after sexual maturity, with very few animals reaching maximum size, is a pattern observed in many modern large mammals, including elephants, African buffalo , and rhinoceros . The same pattern is also seen in other tyrannosaurids. The comparison with modern animals and other tyrannosaurids lends support to this life history hypothesis, but bias in the fossil record may still play
2562-427: 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. ;
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#17328844174492684-455: 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
2806-778: A tyrannosauroid and that the distal metatarsal could have been from an ornithomimosaur . Brownstein also placed the pedal phalanges in Ornithimimosauria, though he did not create a lectotype for Laelaps macropus. Dryptosaurus is estimated to have been 7.5 metres (25 ft) long and 756–1,500 kilograms (1,667–3,307 lb), although this is based on partial remains of one individual. Like its relative Eotyrannus , Dryptosaurus seems to have had relatively long arms when compared with more derived tyrannosaurs, such as Tyrannosaurus . Its hands, which are also relatively large, were once believed to have had three fingers. Brusatte et al. (2011), however, observed an overall similarity in
2928-436: Is a consequence of life history , rather than bias, and that fossils of juvenile Albertosaurus are rare because they simply did not die as often as adults did. A hypothesis of Albertosaurus life history postulates that hatchlings died in large numbers, but have not been preserved in the fossil record because of their small size and fragile construction. After just two years, juveniles were larger than any other predator in
3050-400: Is a fragmentary skeleton belonging to a single adult individual, ANSP 9995. ANSP 9995 consists of a fragmentary right maxilla , a fragmentary right dentary , a fragmentary right surangular , lateral teeth, 11 middle-distal caudal vertebrae , both the left and right humeri , three manual phalanges from the left hand (I-1, II-2, and an ungual), the shafts of the left and right pubic bones,
3172-472: Is a valid taxon . On August 11, 1910, American paleontologist Barnum Brown discovered the remains of a large group of Albertosaurus at another quarry alongside the Red Deer River. Because of the large number of bones and the limited time available, Brown's party did not collect every specimen, but made sure to collect remains from all of the individuals that they could identify in the bone bed . Among
3294-538: Is among the first theropod dinosaurs ever known to science. Up until 1866, theropods from the Americas were only known from isolated teeth discovered by Ferdinand Van Hayden during Geological Survey excursions into Montana . During the summer of 1866, workers from the West Jersey Marl Company uncovered an incomplete theropod skeleton in a quarry near Barnsboro , New Jersey with sediments belonging to
3416-538: Is by Loewen et al. (2013). Proceratosaurus bradleyi Kileskus aristotocus Guanlong wucaii Sinotyrannus kazuoensis Juratyrant langhami Stokesosaurus clevelandi Dilong paradoxus Eotyrannus lengi Bagaraatan ostromi Raptorex kriegsteini Dryptosaurus aquilunguis Alectrosaurus olseni Xiongguanlong baimoensis Appalachiosaurus montgomeriensis Alioramus altai Alioramus remotus Tyrannosauridae Brownstein (2021) found Dryptosaurus to be
3538-413: Is demarcated anteriorly by the mesiodistal crest and demarcated medially by a novel crest) the presence of a proximomedially trending ridge on the anterior surface of the fibula immediately proximal to the iliofibularis tubercle, the lip on the lateral surface of the lateral condyle of the astragalus being prominent and overlapping the proximal surface of the calcaneum , and metatarsal IV being observed with
3660-596: 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
3782-581: Is housed in the Royal Ontario Museum in Toronto . No Albertosaurus fossils were found from 1926 to 1972, but there has been an increase in findings since then. Apart from the Dry Island bonebed, six more skulls and skeletons have since been discovered in Alberta and are housed in various Canadian museums. Specimen RTMP 81.010.001 was found in 1978 by amateur paleontologist Maurice Stefanuk. RTMP 85.098.001
Albertosaurus - Misplaced Pages Continue
3904-440: Is no longer preserved on the original specimens, which have significantly degraded due to pyrite disease. The discovery of this genus gave North American paleontologists the opportunity to observe an articulated, albeit incomplete, theropod skeleton. During the late 19th century, this genus unfortunately became a wastebasket taxon for the referral of isolated theropod elements from across North America, given that Tyrannosauroidea
4026-436: Is observed in modern Komodo dragons, with hatchlings beginning life as small insectivores before growing to become the dominant predators on their islands. However, as the preservation of behaviour in the fossil record is exceedingly rare, these ideas cannot readily be tested. In 2010, Currie, though still favouring the hunting pack hypothesis, admitted that the concentration could have been brought about by other causes, such as
4148-519: Is only 3% longer than the tibia. The longest manual ungual phalanx recovered measured 176 mm (6.9 in) in length. The morphology of the proximal portion of metatarsal IV suggests that Dryptosaurus had an arctometatarsalian foot, an advanced feature shared by derived tyrannosauroids, such as Albertosaurus and Tyrannosaurus , in which the third metatarsal is "pinched" between the second and fourth metatarsals. According to Brusatte et al. (2011), Dryptosaurus can be distinguished based on
4270-514: Is plentiful evidence for gregarious behaviour among herbivorous dinosaurs, including ceratopsians and hadrosaurs . However, only rarely are so many dinosaurian predators found at the same site. Small theropods, like Deinonychus and Coelophysis , have been found in aggregations, as have larger predators, such as Allosaurus and Mapusaurus . There is some evidence of gregarious behaviour in other tyrannosaurids as well, as fragmentary remains of smaller individuals were found alongside " Sue ",
4392-460: 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,
4514-474: 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
4636-482: Is the cladogram of Tyrannosauridae based on the phylogenetic analysis conducted by Loewen et al. in 2013. Gorgosaurus libratus Albertosaurus sarcophagus Dinosaur Park tyrannosaurid Daspletosaurus torosus Daspletosaurus horneri Teratophoneus curriei Bistahieversor sealeyi Lythronax argestes Tyrannosaurus rex Tarbosaurus bataar Zhuchengtyrannus magnus Most age categories of Albertosaurus are represented in
4758-471: Is today seen as a juvenile form of Gorgosaurus libratus and the latter is seen as either identical to Tyrannosaurus or representing a separate genus, Nanotyrannus . In 1988, Gregory S. Paul based Albertosaurus megagracilis on a small tyrannosaurid skeleton, specimen LACM 28345, from the Hell Creek Formation of Montana. It was renamed Dinotyrannus in 1995, but is now thought to represent
4880-589: The Albertosaurus remains of the Dry Island bonebed, the bones of the small theropod Albertonykus were found. Adult Albertosaurus were the apex predators in their environment, with intermediate niches possibly filled by juvenile Albertosaurus . [REDACTED] [REDACTED] [REDACTED] 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
5002-717: The Albertosaurus - Gorgosaurus situation may be clarified once these are fully described. Most authors have followed Currie's recommendation, but some have not. In 1930, Anatoly Nikolaevich Riabinin named Albertosaurus pericolosus based on a tooth from China that probably belonged to Tarbosaurus . In 1932, Friedrich von Huene renamed Dryptosaurus incrassatus , not considered a nomen dubium by him, to Albertosaurus incrassatus . Because he had identified Gorgosaurus with Albertosaurus , in 1970, Russell also renamed Gorgosaurus sternbergi (Matthew & Brown 1922) into Albertosaurus sternbergi and Gorgosaurus lancensis (Gilmore 1946) into Albertosaurus lancensis . The former species
Albertosaurus - Misplaced Pages Continue
5124-590: The Allosaurus -like characteristics of the teeth are primitive to theropods as a whole and may have been present in other large-bodied Morrison Formation theropod species . Brusatte et al. (2011) noted that well-preserved, historic casts of most of the type material from ANSP 9995 and AMNH FARB 2438 are housed in the collections of the Natural History Museum in London (NHM OR50100). The casts show some detail that
5246-539: The Cleveland-Lloyd Dinosaur Quarry in Utah . The group seems to be composed of one very old adult, eight adults between 17 and 23 years old, seven sub-adults undergoing their rapid growth phases at between 12 and 16 years old, and six juveniles between the ages of 2 and 11 years old that had not yet reached the growth phase. The near-absence of herbivore remains and the similar state of preservation common to
5368-609: The Horseshoe Canyon Formation alongside the Red Deer River in Alberta. It was recovered by an expedition of the Geological Survey of Canada , led by the famous geologist Joseph Burr Tyrrell . Due to a lack of specialised equipment, the almost complete skull could only be partially secured. In 1889, Tyrrell's colleague Thomas Chesmer Weston found an incomplete smaller skull associated with some skeletal material at
5490-621: 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
5612-799: 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;
5734-588: The Maastrichtian -aged New Egypt Formation . In August of 1866, paleontologist Edward Drinker Cope was notified of the discovery and encouraged to visit the marl pit to obtain the specimen. When he arrived, he was thoroughly surprised by the skeleton's completeness and uniqueness, calling it the "finest discovery I have yet made". The skeleton was then deposited at the Academy of Natural Sciences in Philadelphia under
5856-819: The Tyrannosaurus mounted in the Field Museum of Natural History in Chicago , and a bonebed in the Two Medicine Formation of Montana contains at least three specimens of Daspletosaurus preserved alongside several hadrosaurs. These findings may corroborate the evidence for social behaviour in Albertosaurus , although some or all of the above localities may represent temporary or unnatural aggregations. Others have speculated that, instead of social groups, at least some of these finds represent Komodo dragon -like mobbing of carcasses, where aggressive competition leads to some of
5978-440: The fossil record . Using bone histology , the age of an individual animal at the time of death can often be determined, allowing growth rates to be estimated and compared with other species. The youngest known Albertosaurus is a two-year-old discovered in the Dry Island bonebed, which would have weighed about 50 kilograms (110 lb ) and measured slightly more than 2 metres (6.6 feet) long. The 10 metres (33 feet) specimen from
6100-404: 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,
6222-565: The specific name is derived from the Ancient Greek term σαρκοφάγος ( sarkophagos ), meaning "flesh-eating", and having the same etymology as the funeral container with which it shares its name, which is a combination of the Greek words σαρξ/ sarx ("flesh") and φαγειν / phagein ("to eat"). More than 30 specimens of all ages are known to science. The type specimen is a partial skull collected on June 9, 1884, from an outcrop of
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#17328844174496344-469: 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
6466-642: The Maastrichtian stage, the Western Interior Seaway, which stretched in a north–south direction from the present-day Arctic Ocean down to the Gulf of Mexico, separated Dryptosaurus and its coeval fauna from western North America, which was dominated by the much larger tyrannosaurids. Although certainly a carnivore, the paucity of known Cretaceous East Coast dinosaurs make ascertaining the specific diet of Dryptosaurus very difficult. Hadrosaurids are known from
6588-462: The US state of Montana . Finding no significant differences to separate the two taxa (due mostly to a lack of good Albertosaurus skull material), Dale Russell declared the name Gorgosaurus a junior synonym of Albertosaurus , which had been named first, and G. libratus was renamed Albertosaurus libratus in 1970. A species distinction was maintained because of the age difference. The addition extended
6710-434: The animals' lives. Sexual maturation while still actively growing appears to be a shared trait among small and large dinosaurs, as well as in large mammals like humans and elephants . This pattern of relatively early sexual maturation differs strikingly from the pattern in birds, which delay their sexual maturity until after they have finished growing. During growth, thickening of the tooth morphology changed so much that, had
6832-418: The association of young and adult skeletons on the Dry Island bonebed not proven that they belonged to the same taxon, the teeth of juveniles would likely have been identified by statistical analysis as those of a different species. Most known Albertosaurus individuals were aged 14 years or older at the time of death. Juvenile animals are rarely fossilized for several reasons, mainly preservation bias , where
6954-442: 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
7076-603: The bones deposited in the American Museum of Natural History collections in New York City are seven sets of right metatarsals , along with two isolated toe bones that did not match any of the metatarsals in size. This indicated the presence of at least nine individuals in the quarry. Palaeontologist Philip J. Currie of the Royal Tyrrell Museum of Palaeontology rediscovered the bonebed in 1997 and resumed fieldwork at
7198-446: The catalogue number ANSP 9995 and includes; skull and dentary fragments, teeth , caudal vertebrae , humeri , an incomplete manus , a partial pelvis , and nearly complete left hindlimb . However, four chevrons , a sternum , and a scapula which are now lost were also noted by Cope in addition to several sacral vertebrae which are now referred to the protostegid Pneumatoarthrus . An isolated metatarsal possibly belonging to
7320-558: The crack-like serrations of their teeth from spreading when subjected to the forces of feeding. Albertosaurus is a member of the theropod family Tyrannosauridae, specifically the subfamily Albertosaurinae. Its closest relative is the slightly older Gorgosaurus libratus (sometimes called Albertosaurus libratus ; see below). These two species are the only described albertosaurines, but other undescribed species may exist. Thomas Holtz found Appalachiosaurus to be an albertosaurine in 2004, but his more recent unpublished work places it as
7442-425: The dentary in 1877, but it has since been lost. Later L. trihedrodon was moved the genus Antrodemus , now Allosaurus , based off its derivation but it is now considered a nomen dubium . Five damaged partial tooth crowns from AMNH 5780, mistakenly thought to have belonged to the L. trihedrodon holotype, share many features in common with Allosaurus and probably belong to that genus instead. However, some of
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#17328844174497564-465: The earliest depiction of theropods as highly active and dynamic animals. Knight's artistic hand was guided by E. D. Cope and reflects their progressive opinion about theropod agility, despite their large size, as well as the opinion of Henry Fairfield Osborn , the curator of vertebrate paleontology at the American Museum of Natural History at the time of the painting's commission. The original painting
7686-572: The early Maastrichtian age of the Late Cretaceous period, about 70 to 68 million years ago. Immediately below this formation is the Bearpaw Shale , a marine formation representing a section of the Western Interior Seaway . The Inland Sea was receding as the climate cooled and sea levels subsided towards the end of the Cretaceous, thus exposing land that had previously been underwater. It
7808-598: The end of the Maastrichtian age of the Late Cretaceous period. Dryptosaurus was a large, bipedal , ground-dwelling carnivore that could grow up to 7.5 metres (25 ft) long and weigh up to 756–1,500 kilograms (1,667–3,307 lb). Although it is now largely unknown outside of academic circles, the famous 1897 painting of the genus by Charles R. Knight made Dryptosaurus one of the more widely known dinosaurs of its time, in spite of its poor fossil record. First described by Edward Drinker Cope in 1866 and later renamed by Othniel Charles Marsh in 1877, Dryptosaurus
7930-550: The first discovery in 1884, fossils of more than 30 individuals have been recovered that provide scientists with a more detailed knowledge of Albertosaurus anatomy than what is available for most other tyrannosaurids. The discovery of 26 individuals in one particular site provides evidence of gregarious behavior and allows for studies of ontogeny and population biology . These are near impossible with lesser-known dinosaurs because their remains are rarer and more fragmentary when compared to those of Albertosaurus . Albertosaurus
8052-508: The fish fauna. Mammals included multituberculates and the marsupial Didelphodon . The saltwater plesiosaur Leurospondylus has been found in marine sediments in the Horseshoe Canyon, while freshwater environments were populated by turtles , Champsosaurus , and crocodilians like Leidyosuchus and Stangerochampsa . Dinosaurs dominate the fauna, especially hadrosaurs, which make up half of all dinosaurs known. These include
8174-411: The following characteristics: the combination of a reduced humerus (humerus: femur ratio = 0.375) and a large hand (phalanx I-1:femur ratio = 0.200), the strong mediolateral expansion of the ischial tubercle, which is approximately 1.7 times as wide as the shaft immediately distally, the presence of an ovoid fossa on the medial surface of the femoral shaft immediately proximal to the medial condyle (which
8296-446: 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
8418-412: The genera Edmontosaurus , Saurolophus , and Hypacrosaurus . Ceratopsians and ornithomimids were also very common, together making up another third of the known fauna. Along with much rarer ankylosaurians and pachycephalosaurs , all of these animals would have been prey for a diverse array of carnivorous theropods, including troodontids , dromaeosaurids , and caenagnathids . Intermingled with
8540-727: 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,
8662-477: The genus Albertosaurus . Two specimens from "cf Albertosaurus ".sp" have been found in Mexico ( Packard Formation and Corral de Enmedio Formation ). In 1913, paleontologist Charles H. Sternberg recovered another tyrannosaurid skeleton from the slightly older Dinosaur Park Formation in Alberta. Lawrence Lambe named this dinosaur Gorgosaurus libratus in 1914. Other specimens were later found in Alberta and
8784-483: The genus is named, although an indeterminate species ("cf. Albertosaurus sp.") has been discovered in the Corral de Enmedio and Packard Formations of Mexico . Scientists disagree on the content of the genus and some recognize Gorgosaurus libratus as a second species. As a tyrannosaurid, Albertosaurus was a bipedal predator with short arms, two-fingered hands, and a massive head with dozens of large, sharp teeth,
8906-469: The health of the Dry Island Albertosaurus assembly was reported upon. Most specimens showed no sign of disease. On three phalanges of the foot, strange bony spurs that consisted of abnormal ossifications of the tendons, so-called enthesophytes , were present, but their cause is unknown. Two ribs and a belly-rib showed signs of breaking and healing. One adult specimen had a left lower jaw showing
9028-456: The high physiological demands of procreation, including stress and injuries received during intraspecific competition for mates and resources, and the eventual, ever-increasing effects of senescence . The higher mortality rate in adults may explain their more common preservation. Very large animals were rare because few individuals survived long enough to attain such size. High infant mortality rates, followed by reduced mortality among juveniles and
9150-454: The holotype of A. arctunguis (now referred to A. sarcophagus ), had a 2.5 by 3.5 cm (0.98 by 1.38 in) deep hole in the iliac blade , although the describer of the species did not recognize this as pathological. The specimen also contains some exostosis on the fourth left metatarsal. In 1970, two of the five Albertosaurus sarcophagus specimens with humeri were reported by Dale Russel as having pathological damage to them. In 2010,
9272-432: 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
9394-628: 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,
9516-438: 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. Dryptosaurus Dryptosaurus ( / ˌ d r ɪ p t oʊ ˈ s ɔːr ə s / DRIP -toh- SOR -əs ) is a genus of eutyrannosaurian theropod dinosaur that lived on the island continent of Appalachia approximately 67.6 million years ago during
9638-420: The magnitude of the growth rate, but not the overall pattern. Tyrannosaurids similar in size to Albertosaurus had similar growth rates, although the much larger Tyrannosaurus rex grew at almost five times this rate (601 kilograms [1,325 pounds] per year) at its peak. The end of the rapid growth phase suggests the onset of sexual maturity in Albertosaurus , although growth continued at a slower rate throughout
9760-528: The many individuals at the Albertosaurus bonebed quarry led Currie to conclude that the locality was not a predator trap, such as the La Brea Tar Pits in California , and that all of the preserved animals died at the same time. Currie claims this as evidence of pack behavior. Other scientists are skeptical, observing that the animals may have been driven together by a drought, flood, or other reasons. There
9882-434: The maximum force, by the back teeth, reaching 3,413 Newtons. Above the eyes were short bony crests that may have been brightly coloured in life and possibly used, by males in particular, in courtship to attract a mate. In 2001, William Abler observed that Albertosaurus tooth serrations resemble a crack in the tooth ending in a round void called an ampulla. Tyrannosaurid teeth were used as holdfasts for pulling flesh off
10004-403: The minimum number of individuals present had been established at 12 (on the basis of preserved elements that occur only once in a skeleton) and at 26 if mirrored elements were counted when differing in size due to ontogeny . A total of 1,128 Albertosaurus bones had been secured, which is the largest concentration of large theropod fossils known from the Cretaceous. In 1911, Barnum Brown, during
10126-403: 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
10248-404: The mouth. The premaxillary teeth at the tip of the upper jaw, four per side, were much smaller than the rest, more closely packed, and D-shaped in cross section . Like with Tyrannosaurus rex , the maxillary (cheek) teeth of Albertosaurus were adapted in general form to resist lateral forces exerted by a struggling prey animal. The bite force of Albertosaurus was less formidable, however, with
10370-428: 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
10492-521: The new name Albertosaurus sarcophagus in 1905. He did not describe the remains in any great detail, citing Lambe's complete description the year before. Both specimens, the holotype CMN 5600 and the paratype CMN 5601, are stored in the Canadian Museum of Nature in Ottawa . By the early twenty-first century, some concerns had arisen that, due to the damaged state of the holotype, Albertosaurus might be
10614-774: The only known theropods with preserved feature scales. Another skin impression is from an unknown part of the body. These scales are small, diamond-shaped, and arranged in rows. The massive skull of Albertosaurus , which was perched on a muscular, short, S-shaped neck, was about 1 metre (3.3 feet) long in the largest adults. Wide openings in the skull, called fenestrae , provided space for muscle attachment sites and sensory organs that reduced its overall weight. Its long jaws contained, both sides combined, 58 or more banana-shaped teeth. Larger tyrannosaurids possessed fewer teeth, but Gorgosaurus had 62. Unlike most theropods, Albertosaurus and other tyrannosaurids were heterodont , with teeth of different forms depending on their position in
10736-509: The ornithomimid Coelosaurus , distinguishing it from Dryptosaurus by its longer toes. Thomas R. Holtz listed it as an indeterminate tyrannosauroid in his contribution to the second edition of the Dinosauria . In 2017, it was informally given the new generic name " Teihivenator " . Earlier that year, Brownstein (2017) analyzed the material of Laelaps macropus and found that only the partial tibia could be definitely classified as that of
10858-501: The other vertebrate fossils from the formation, Albertosaurus remains are found in deposits laid down in the deltas and floodplains of large rivers during the later half of Horseshoe Canyon times. The fauna of the Horseshoe Canyon Formation is well-known, as vertebrate fossils, including those of dinosaurs, are very common. Sharks , rays , sturgeons , bowfins , gars , and the gar-like Aspidorhynchus made up
10980-466: The predators being killed and even cannibalized . The evidence of cannibalism was later reported in 2024 by Coppock and Currie. Currie has also speculated on the pack-hunting habits of Albertosaurus . The leg proportions of the smaller individuals were comparable to those of ornithomimids , which were probably among the fastest dinosaurs. Younger Albertosaurus were probably equally fleet-footed or at least faster than their prey. Currie hypothesized that
11102-526: 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
11224-496: The region, aside from adult Albertosaurus , and more fleet-footed than most of their prey animals. This resulted in a dramatic decrease in their mortality rate and a corresponding rarity of fossil remains. Mortality rates doubled at age twelve, perhaps the result of the physiological demands of the rapid growth phase, and then doubled again with the onset of sexual maturity between the ages of fourteen and sixteen. This elevated mortality rate continued throughout adulthood, perhaps due to
11346-434: The remains in detail in 1903 and 1904, which was a combination first coined by Oliver Perry Hay in 1902. Shortly later, Osborn pointed out that D. incrassatus was based on generic tyrannosaurid teeth, so the two Horseshoe Canyon skulls could not be confidently referred to that species. The Horseshoe Canyon skulls also differed markedly from the remains of D. aquilunguis , type species of Dryptosaurus , so Osborn gave them
11468-631: The rest. Albertosaurus may have been able to reach walking speeds of 14–21 km/hour (8–13 mi/hour). At least for the younger individuals, a high running speed is plausible. Two skin impressions from Albertosaurus are known, and both show scales . One patch was found associated with some gastralic ribs and the impression of a long, unknown bone, indicating that the patch is from the belly. The scales are pebbly and gradually become larger and somewhat hexagonal in shape. Also preserved are two larger feature scales, placed 4.5 cm apart from each other, making Albertosaurus , along with Carnotaurus ,
11590-507: The same quarry is 28 years old, the oldest and largest one known. When specimens of intermediate age and size are plotted on a graph, an S -shaped growth curve results, with the most rapid growth occurring in a four-year period ending around the sixteenth year of life, a pattern also seen in other tyrannosaurids. The growth rate during this phase was 122 kilograms (269 pounds) per year, based on an adult weighing 1.3 tonnes . Other studies have suggested higher adult weights, which would affect
11712-422: The same time and place as Dryptosaurus , the island continent of Appalachia , and they may have been a prominent part of its diet. Nodosaurs were also present, although they were less likely to be hunted due to their armor plating. When hunting, both the skull and hands were important for the capture and processing of prey. The 1897 watercolor painting by Charles R. Knight titled Leaping Laelaps may represent
11834-513: The second year of the American Museum of Natural History's operations in Alberta, uncovered a fragmentary partial Albertosaurus skull at the Red Deer River near Tolman Bridge (specimen AMNH 5222). William Parks described a new species in 1928, Albertosaurus arctunguis , based on a partial skeleton lacking a skull that was excavated by Gus Lindblad and Ralph Hornell near the Red Deer River in 1923, but this species has been considered identical to A. sarcophagus since 1970. Parks' specimen (ROM 807)
11956-494: The shape of the available phalanges of Dryptosaurus with those of derived tyrannosaurids and noted that Dryptosaurus may have had only two functional digits. Each of its fingers were tipped with an eight-inch long, talon-like claw. Its arm morphology suggests that arm reduction in tyrannosauroids may not have proceeded in a uniform fashion. Dryptosaurus may have used both its arms and its jaws and as weapons when hunting, capturing, and processing its prey. The type specimen
12078-797: The sister taxon to " Cryptotyrannus ", an informally named theropod from the Merchantville Formation of Delaware . Brownstein (2021) also reinstated the family Dryptosauridae , which now includes both "Cryptotyrannus" and Dryptosaurus . The type specimen of Dryptosaurus is ANSP 9995 and was recovered in the West Jersey Marl Company Pit, in what came to be known as the New Egypt Formation in Barnsboro, Mantua Township, in Gloucester County , New Jersey . The specimen
12200-437: The site, which is now located inside Dry Island Buffalo Jump Provincial Park . Further excavation from 1997 to 2005 turned up the remains of 13 more individuals of various ages, including a diminutive two-year-old and a very old individual estimated at over 10 metres (33 feet) long. None of these individuals are known from complete skeletons and most are represented by remains in both museums. Excavations continued until 2008, when
12322-471: The skeleton was found at the same locale, but this has come into question. Cope presented his description of the specimen to the Academy on August 21, 1866, naming it a new genus and species of dinosaur, Laelaps aquilunguis . " Laelaps ", which is derived from the Greek word "hurricane" or "storm wind", was also the name of a dog in Greek mythology who never failed to catch what it was hunting. The genus name
12444-407: The smaller bones of younger animals were less likely to be preserved by fossilization than the larger bones of adults, and collection bias, where smaller fossils are less likely to be noticed by collectors in the field. Young Albertosaurus are relatively large for juvenile animals, but their remains are still rare in the fossil record when compared to adults. It has been suggested that this phenomenon
12566-497: 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,
12688-412: 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
12810-403: 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
12932-409: The temporal range of the genus Albertosaurus earlier by several million years and its geographic range southwards by hundreds of kilometres. In 2003, Philip J. Currie , benefiting from much more extensive finds and a general increase in anatomical knowledge of theropods, compared several tyrannosaurid skulls and came to the conclusion that the two species are more distinct than previously thought. As
13054-469: The three alveoli in full and the fourth only partially. The authors were able to ascertain that Dryptosaurus had ziphodont dentition. The shape of the alveolus situated on the anterior portion of the fragment suggests that it housed a tooth that was smaller and more circular than the others. This incisiform tooth is common among tyrannosauroids. The disarticulated teeth recovered are transversely narrow, serrated (17–18 denticles /cm), and recurved. The femur
13176-492: The two species are sister taxa , they are more closely related to each other than to any other species of tyrannosaurid. Recognizing this, Currie nevertheless recommended that Albertosaurus and Gorgosaurus be kept as separate genera, as he concluded that they were no more similar than Daspletosaurus and Tyrannosaurus , which are almost always separated. In addition to this, several albertosaurine specimens have been recovered from Alaska and New Mexico . Currie suggested that
13298-566: 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
13420-429: 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
13542-427: The younger members of the pack may have been responsible for driving their prey towards the adults, who were larger and more powerful, but also slower. Juveniles may also have had different lifestyles than adults, filling predator niches between the enormous adults and the smaller contemporaneous theropods, the largest of which were two orders of magnitude smaller than adult Albertosaurus in mass. A similar situation
13664-405: Was a fairly large bipedal predator, but smaller than Tarbosaurus and Tyrannosaurus rex . Typical Albertosaurus adults measured up to 8–9 m (26–30 ft) long and weighed between 1.7 and 3.0 metric tons (1.9 and 3.3 short tons) in body mass. Albertosaurus shared a similar body appearance with all other tyrannosaurids, Gorgosaurus in particular. Typical for a theropod, Albertosaurus
13786-414: Was also a basal tyrannosauroid . Detailed phylogenetic analysis by Brusatte et al. (2013) confirmed the tyrannosauroid affinities of Dryptosaurus and assigned it as an "intermediate" tyrannosauroid that is more derived than basal taxa, such as Guanlong and Dilong , but more primitive than members of the more derived Tyrannosauridae . The following cladogram containing almost all tyrannosauroids
13908-463: Was also supported by the work of Baird and Horner (1979), but did not have wide acceptance until a new discovery was made in 2005. Dryptosaurus was the only large carnivore known in eastern North America until the discovery of the basal tyrannosauroid Appalachiosaurus in 2005. Appalachiosaurus , which is known from more complete remains, is similar to Dryptosaurus in both body size and morphology. This discovery made it clear that Dryptosaurus
14030-451: Was also supported by the work of Russell (1970) and Molnar (1990). Other phylogenetic studies during the 1990s suggested that Dryptosaurus was a coelurosaur , though its exact placement within that group remained uncertain. In 1946, Charles W. Gilmore was the first to observe that certain anatomical features may link Dryptosaurus with coeval Late Cretaceous tyrannosaurids, Albertosaurus , and Tyrannosaurus . This observation
14152-405: Was bipedal and balanced its large, heavy head and torso with a long, muscular tail. However, tyrannosaurid forelimbs were extremely small for their body size and retained only two functional fingers, the second being longer than the first. The legs were long and ended in a four-toed foot on which the first toe, the hallux , was very short and did not reach the ground. The third toe was longer than
14274-644: Was collected by quarry workers in marl and sandstone that were deposited during the late Maastrichtian stage of the Late Cretaceous period, approximately 67 million years ago. Studies suggest that the New Egypt Formation is a marine unit and it is considered to be the deeper-water equivalent of the Tinton and Red Bank formations. This formation overlies the Navesink Formation , from which potential Dryptosaurus referred material has been reported. During
14396-539: Was found by Stefanuk on June 16, 1985. RTMP 86.64.001 was found in December 1985. RTMP 86.205.001 was found in 1986. RTMP 97.058.0001 was found in 1996 and then there is CMN 11315. Unfortunately, none of these skeletons were found with complete skulls. Fossils have also been reported from the American states of Montana, New Mexico, Wyoming , and Missouri , but they are doubted to be from A. sarcophagus and may not even belong to
14518-525: Was named by Henry Fairfield Osborn in a one-page note at the end of his 1905 description of Tyrannosaurus rex . Its namesake is Alberta , the Canadian province established the very same year where the first remains were found. The generic name also incorporates the Greek word σαυρος / sauros , meaning "lizard", which is the most common suffix in dinosaur names. The type species is Albertosaurus sarcophagus and
14640-489: Was not a smooth process, however, and the seaway would periodically rise to cover parts of the region throughout Horseshoe Canyon before finally receding altogether in the years after. Due to the changing sea levels, many different environments are represented in the Horseshoe Canyon Formation, including offshore and near-shore marine habitats and coastal habitats, such as lagoons , estuaries , and tidal flats . Numerous coal seams represent ancient peat swamps . Like most of
14762-515: Was not recognized as a distinct group of large theropods at the time and numerous theropod species were assigned to it (often as Lælaps or Laelaps ), only to be later reclassified. Laelaps trihedrodon was coined by Cope in 1877 for a partial dentary (now missing) from the Morrison Formation of Colorado. Laelaps macropus was also coined by Cope for a partial leg found in the Navesink Formation that Joseph Leidy had referred earlier to
14884-635: Was occupied by a mite and replaced by the name Dryptosaurus, "slashing reptile", by Othniel Marsh , Cope's rival in the Bone Wars , in 1877. However, Cope maintained that the name Laelaps was valid for years after, refusing to use Dryptosaurus . Also in the 1870s, a partial dentary of a theropod was unearthed from the Late Jurassic strata of the Morrison Formation outside Canon City, Colorado. Cope coined Laelaps trihedrodon , "three hedged tooth", for
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