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103-564: Giganotosaurus ( / ˌ ɡ ɪ ɡ ə ˌ n oʊ t ə ˈ s ɔː r ə s / GIG -ə- NOH -tə- SOR -əs ) is a genus of theropod dinosaur that lived in what is now Argentina , during the early Cenomanian age of the Late Cretaceous period , approximately 99.6 to 95 million years ago. The holotype specimen was discovered in the Candeleros Formation of Patagonia in 1993 and is almost 70% complete. The animal

206-557: 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 ,

309-411: A 1 t (1.1 short tons) mammalian carnivore, and would have supported rapid growth. In 2001, the physicist Rudemar Ernesto Blanco and Mazzetta evaluated the cursorial (running) capability of Giganotosaurus . They rejected the hypothesis by James O. Farlow that the risk of injuries involved in such large animals falling while on a run, would limit the speed of large theropods. Instead they posed that

412-402: A bite was delivered against prey. Giganotosaurus is thought to have been the apex predator of its ecosystem , and it may have fed on juvenile sauropod dinosaurs. In 1993, the amateur Argentine fossil hunter Rubén Darío Carolini  [ es ] discovered the tibia (lower leg bone) of a theropod dinosaur while driving a dune buggy in the badlands near Villa El Chocón , in

515-399: A body mass larger than other adult Tyrannosaurus . They noted that these theropods were known by far fewer specimens than Tyrannosaurus , and that future finds may reveal specimens larger than "Scotty", as indicated by the large Giganotosaurus dentary. While "Scotty" had the greatest femoral circumference, the femoral length of Giganotosaurus was about 10% longer, but the authors stated it

618-405: A broad "shelf" over the orbit, and the squared front end of the lower jaw. As more carcharodontosaurids were discovered, their interrelationships became clearer. The group was defined as all allosauroids closer to Carcharodontosaurus than Allosaurus or Sinraptor by the paleontologist Thomas R. Holtz and colleagues in 2004. In 2006, Coria and Currie united Giganotosaurus and Mapusaurus in

721-479: A groove ran along it, which supported foramina that nourished the teeth. The inner side of the dentary had a row of interdental plates , where each tooth had a foramen. The Meckelian groove ran along the lower border. The curvature of the dentary shows that the mouth of Giganotosaurus would have been wide. It is possible that each dentary had twelve alveoli (tooth sockets). Most of the alveoli were about 3.5 cm (1.3 in) long from front to back. The teeth of

824-569: A heavier animal. They estimated the skull to have been about 1.53 m (5 ft) long, and the whole animal to have been 12.5 m (41 ft) long, with a weight of about 6 to 8 t (6.6 to 8.8 short tons). In 1996, the paleontologist Paul Sereno and colleagues described a new skull of the related genus Carcharodontosaurus from Morocco, a theropod described in 1927 but previously known only from fragmentary remains (much of its fossils were destroyed in World War II ). They estimated

927-426: A high-speed pursuit predator . They suggested that these findings would also apply to other long-limbed giant theropods such as Giganotosaurus , Mapusaurus , and Acrocanthosaurus . In 2002, Coria and Currie found that various features of the rear part of the skull (such as the frontwards slope of the occiput and low and wide occipital condyle) indicate that Giganotosaurus would have had a good capability of moving

1030-651: 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

1133-411: A length of 13.2 m (43 ft), a skull 1.95 m (6.4 ft) long, and a weight of 8.2 t (9.0 short tons). Some writers have considered the largest size estimates for both specimens exaggerated. Giganotosaurus has been compared to an oversized version of the well-known genus Allosaurus . Though incompletely known, the skull of Giganotosaurus appears to have been low. The maxilla of

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1236-551: A long term or coincidental accumulation of carcasses, the presence of different growth stages of the same taxon indicated the aggregation was not coincidental. In a 2006 National Geographic article, Coria stated that the bonebed was probably the result of a catastrophic event and that the presence of mainly medium-sized individuals, with very few young or old, is normal for animals that form packs. Therefore, Coria said, large theropods may have hunted in groups, which would be advantageous when hunting gigantic sauropods. Giganotosaurus

1339-628: 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,

1442-429: A narrow brevis-shelf (a projection where tail muscles attached). The pubic foot was pronounced and shorter at the front than behind. The ischium was straight and expanded hindwards, ending in a lobe -shape. The femur was sigmoid -shaped, and had a very robust, upwards pointing head, with a deep sulcus (groove). The lesser trochanter of the femoral head was wing-like, and placed below the greater trochanter , which

1545-454: A new specimen scaled up to match the snout described by Dal Sasso and colleagues. This would make Spinosaurus the largest known carnivorous dinosaur. In 2019, the paleontologist W. Scott Persons and colleagues described a Tyrannosaurus specimen (nicknamed "Scotty"), and estimated it to be more massive than other giant theropods, but cautioned that the femoral proportions of the carcharodontosaurids Giganotosaurus and Tyrannotitan indicated

1648-506: A new theropod taxon . Calvo and Coria found the dentary to be identical to that of the holotype, though 8% larger at 62 cm (24 in). Though the rear part of it is incomplete, they proposed that the skull of the holotype specimen would have been 1.80 m (6 ft) long, and estimated the skull of the larger specimen to have been 1.95 m (6.4 ft) long, the longest skull of any theropod. In 1999, Calvo referred an incomplete tooth, (MUCPv-52), to Giganotosaurus ; this specimen

1751-406: A photo of the leg-bone. The partial skull was scattered over an area of about 10 m (110 sq ft), and the postcranial skeleton was disarticulated. The specimen preserved almost 70% of the skeleton, and included most of the vertebral column , the pectoral and pelvic girdles, the femora, and the left tibia and fibula. In 1995, this specimen was preliminarily described by Coria and Salgado, who made it

1854-409: 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

1957-460: A ridge-like crest on the lacrimal bone in front of the eye. The front of the lower jaw was flattened and had a downward-projecting process (or "chin") at the tip. The teeth were compressed sideways and had serrations. The neck was strong and the pectoral girdle proportionally small. Part of the family Carcharodontosauridae , Giganotosaurus is one of the most completely known members of the group, which includes other very large theropods, such as

2060-419: A similarly sized animal with a more robust dentary. He conceded that with only one good Giganotosaurus specimen known, it is possible that larger individuals will be found, as it took most of a century to find "Sue" after Tyrannosaurus was discovered. In 2014, the paleontologist Nizar Ibrahim and colleagues estimated the length of Spinosaurus to have been over 15 m (49 ft), by extrapolating from

2163-505: A size range for a species based on few, incomplete specimens, and both paleontologists agreed that other aspects of these dinosaurs were more important than settling the "size contest". In 1998, the paleontologist Jorge O. Calvo and Coria assigned a partial left dentary bone (part of the lower jaw) containing some teeth (MUCPv-95) to Giganotosaurus . It had been collected by Calvo near Los Candeleros in 1988 (found in 1987), who described it briefly in 1989, while noting it may have belonged to

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2266-432: A skull between 1.53 and 1.80 m (5.0 and 5.9 ft) long, a femur (thigh bone) between 1.365 and 1.43 m (4.48 and 4.69 ft) long, and a weight between 4.2 and 13.8 t (4.6 and 15.2 short tons). Fusion of sutures (joints) in the braincase indicates the holotype specimen was a mature individual. A second specimen, consisting of a dentary bone from a supposedly larger individual, has been used to extrapolate

2369-426: A supposedly larger individual has been used to extrapolate a length of 13.2 m (43 ft). Some researchers have found the animal to be larger than Tyrannosaurus , which has historically been considered the largest theropod, while others have found them to be roughly equal in size and the largest size estimates for Giganotosaurus exaggerated. The skull was low, with rugose (rough and wrinkled) nasal bones and

2472-427: 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. ;

2575-455: 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

2678-409: A volume of 275 ml (9.7 imp fl oz). The dentary of the lower jaw expanded in height towards the front (by the mandibular symphysis , where the two halves of the lower jaw connected), where it was also flattened, and it had a downwards projection at the tip (which has been referred to as a "chin"). The lower side of the dentary was concave, the outer side was convex in upper view, and

2781-635: A weight 7 to 9 t (7.7 to 9.9 short tons), exceeding the maximum size of all other theropods. In 2006, Coria and Currie described the large theropod Mapusaurus from Patagonia; it was closely related to Giganotosaurus and of approximately the same size. In 2007, the paleontologists François Therrien and Donald M. Henderson found that Giganotosaurus would have approached 13 m (43 ft) in length and 13.8 t (15.2 short tons) in weight, while Carcharodontosaurus would have approached 13.3 m (44 ft) in length and 15.1 t (16.6 short tons) in weight (surpassing Tyrannosaurus ), and estimated

2884-612: 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

2987-458: Is exhibited in an adjacent room. One of the features of theropod dinosaurs that has attracted most scientific interest is the fact that the group includes the largest terrestrial predators of the Mesozoic Era . This interest began with the discovery of one of the first known dinosaurs, Megalosaurus , named in 1824 for its large size. More than half a century later in 1905, Tyrannosaurus

3090-570: Is now housed in the Ernesto Bachmann Paleontological Museum (where it is catalogued as specimen MUCPv-Ch1) in Villa El Chocón, which was inaugurated in 1995 at the request of Carolini. The specimen is the main exhibition at the museum, and is placed on the sandy floor of a room devoted to the animal, along with tools used by paleontologists during the excavation. A mounted reconstruction of the skeleton

3193-741: Is one of the most complete and informative members of Carcharodontosauridae. The following cladogram shows the placement of Giganotosaurus within Carcharodontosauridae according the paleontologist Andrea Cau , 2024: Sauroniops Veterupristisaurus Lusovenator Eocarcharia (holotype skull roof) Concavenator [REDACTED] Carcharodontosaurus iguidensis (holotype maxilla) Eocarcharia (assigned maxilla) Carcharodontosaurus iguidensis (assigned cranial material) Lajasvenator Labocania Carcharodontosaurus saharicus (destroyed holotype) Tyrannotitan Coria and Salgado suggested that

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3296-460: 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,

3399-474: 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

3502-448: Is therefore impossible to determine with certainty whether it was larger than Tyrannosaurus , for example, which has been considered the largest theropod historically. Different size estimates have been reached by several researchers, based on various methods, and depending on how the missing parts of the skeleton have been reconstructed. Length estimates for the holotype specimen have varied between 12 and 13 m (39 and 43 ft), with

3605-697: The Giganotosaurus holotype skull to have been 1.56 m (5 ft) long. They cautioned that these measurements depended on whether the incomplete skulls of these animals had been reconstructed correctly, and that more complete specimens were needed for more accurate estimates. They also found that Dal Sasso and colleagues' reconstruction of Spinosaurus was too large, and instead estimated it to have been 14.3 m (47 ft) long, weighing 20.9 t (23.0 short tons), and possibly as low as 12.6 m (41 ft) in length and 12 t (13 short tons) in weight. They concluded that these dinosaurs had reached

3708-621: 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

3811-824: 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;

3914-540: The Neuquén province of Patagonia , Argentina. Specialists from the National University of Comahue were sent to excavate the specimen after being notified of the find. The discovery was announced by the paleontologists Rodolfo Coria and Leonardo Salgado at a Society of Vertebrate Paleontology meeting in 1994, where science writer Don Lessem offered to fund the excavation, after having been impressed by

4017-549: The convergent evolution of gigantism in theropods could have been linked to common conditions in their environments or ecosystems . Sereno and colleagues found that the presence of carcharodontosaurids in Africa ( Carcharodontosaurus ), North America ( Acrocanthosaurus ), and South America ( Giganotosaurus ), showed the group had a transcontinental distribution by the Early Cretaceous period . Dispersal routes between

4120-493: The holotype of the new genus and species Giganotosaurus carolinii (parts of the skeleton were still encased in plaster at this time). The generic name is derived from the Ancient Greek words gigas/ γίγας (meaning "giant"), notos/ νότος (meaning "austral/southern", in reference to its provenance) and -sauros/- σαύρος (meaning "lizard"). The specific name honors Carolini, the discoverer. The holotype skeleton

4223-404: 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,

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4326-473: 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

4429-442: 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

4532-471: The bones of Giganotosaurus and Tyrannosaurus had very similar oxygen isotope patterns, with similar heat distribution in the body. These thermoregulatory patterns indicate that these dinosaurs had a metabolism intermediate between that of mammals and reptiles, and were therefore homeothermic (with a stable core body-temperature, a type of " warm-bloodedness "). The metabolism of an 8 t (8.8 short tons) Giganotosaurus would be comparable to that of

4635-442: The braincase of Giganotosaurus , Coria and Currie gave a length estimate of 1.60 m (5 ft) for the holotype skull, and calculated a weight of 4.2 t (4.6 short tons) by extrapolating from the 520 mm (20 in) circumference of the femur-shaft. This resulted in an encephalization quotient (a measure of relative brain size) of 1.9. In 2004, the paleontologist Gerardo V. Mazzetta and colleagues pointed out that though

4738-401: The braincase. They pointed out that many contacts between skull bones were not preserved, which lead to the total length of the skull being ambiguous. They found instead that the skulls of Giganotosaurus and Carcharodontosaurus were exactly the same size as that of Tyrannosaurus . They also measured the femur of the Giganotosaurus holotype to be 1.365 m (4 ft) long, in contrast to

4841-460: The carcharodontosaurid subfamily Giganotosaurinae based on shared features of the femur, such as a weak fourth trochanter, and a shallow, broad groove on the lower end. In 2008, Sereno and the paleontologist Stephen L. Brusatte united Giganotosaurus , Mapusaurus , and Tyrannotitan in the tribe Giganotosaurini . In 2010, Paul listed Giganotosaurus as " Giganotosaurus (or Carcharodontosaurus ) carolinii " without elaboration. Giganotosaurus

4944-422: The closely related Mapusaurus and Carcharodontosaurus . Giganotosaurus is thought to have been homeothermic (a type of " warm-bloodedness "), with a metabolism between that of a mammal and a reptile, which would have enabled fast growth. It would have been capable of closing its jaws quickly, capturing and bringing down prey by delivering powerful bites. The "chin" may have helped in resisting stress when

5047-431: The dentary were of similar shape and size, except for the first one, which was smaller. The teeth were compressed sideways, were oval in cross-section, and had serrations at the front and back borders, which is typical of theropods. The teeth were sigmoid-shaped when seen in front and back view. One tooth had nine to twelve serrations per mm (0.039 in). The side teeth of Giganotosaurus had curved ridges of enamel , and

5150-439: The dimensions of the pelvic area and body size in theropods, allowing size estimates for incomplete specimens. Based on this idea, he found Giganotosaurus to have been 12.5 m (41 ft) long, identical to the estimate proposed in the 1995 description. Giganotosaurus is thought to have been one of the largest theropod dinosaurs, but the incompleteness of its remains have made it difficult to estimate its size reliably. It

5253-495: The entire upper surface of this bone. The lacrimal bone in front of the eye had a prominent, rugose crest (or horn) that pointed up at a backwards angle. The crest was ridge-like, and had deep grooves. The postorbital bone behind the eye had a down and backwards directed jugal process that projected into the orbit (eye opening), as seen in Tyrannosaurus , Abelisaurus , and Carnotaurus . The supraorbital bone above

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5356-416: The entirety of the vertebrae and ribs, and the appendicular skeleton , which includes girdles and limbs. In paleontology, there may be disagreement over whether the skull and skeleton belong to the same or different animals. One example is the case of the dinosaur Nemegtosaurus , which is known only from a skull that was found in the same geological formation as the related Opisthocoelicaudia , which

5459-427: The eye that contacted between the lacrimal and postorbital bones was eave -like, and similar to that of Abelisaurus . The quadrate bone at the back of the skull was 44 cm (17 in) long, and had two pneumatic (air-filled) foramina (holes) on the inner side. The skull roof (formed by the frontal and parietal bones ) was broad and formed a "shelf", which overhung the short supratemporal fenestrae at

5562-405: The femur of the Giganotosaurus holotype was larger than that of "Sue", the tibia was 8 cm (3 in) shorter at 1.12 m (4 ft). They found the holotype specimen to have been equal to Tyrannosaurus in size at 8 t (8.8 short tons) (marginally smaller than "Sue"), but that the larger dentary might have represented an animal of 10 t (11 short tons), if geometrically similar to

5665-446: 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

5768-410: The front, and pleurocoels (hollow depressions) divided by laminae (plates). The back (dorsal) vertebrae had high neural arches and deep pleurocoels. The tail (caudal) vertebrae had neural spines that were elongated from front to back and had robust centra. The transverse processes of the caudal vertebrae were long from front to back, and the chevrons on the front were blade-like. The pectoral girdle

5871-737: 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,

5974-586: The holotype specimen. By using multivariate regression equations , these authors also suggested an alternative weight of 6.5 t (7.2 short tons) for the holotype and 8.2 t (9.0 short tons) for the larger specimen, and that the latter was therefore the largest known terrestrial carnivore. In 2005, the paleontologist Cristiano Dal Sasso and colleagues described new skull material (a snout) of Spinosaurus (the original fossils of which were also destroyed during World War II), and concluded this dinosaur would have been 16 to 18 m (52 to 59 ft) long with

6077-432: 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

6180-399: The imbalance caused by increasing velocity would be the limiting factor. Calculating the time it would take for a leg to gain balance after the retraction of the opposite leg, they found the upper kinematic limit of the running speed to be 14 m/s (50 km/h; 31 mph). They also found comparison between the running capability of Giganotosaurus and birds like the ostrich based on

6283-404: The large carcharodontosaurid Meraxes , which has the most completely known Carcharodontosaurine skull, with an estimated length of 1.27 m (4.2 ft). Extrapolating from that skull, they estimated the skull of Giganotosaurus to have been 1.634 m (5.36 ft) long, making it one of the largest known theropod skulls. Henderson suggested in 2023 that there was a close relation between

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6386-400: The larger specimen 8.2 t (9.0 short tons). Tyrannosaurus was estimated to have weighed 8.4 t (9.3 short tons), and Hartman noted that it had a wider torso, though the two seemed similar in side view. He also pointed out that the Giganotosaurus dentary that was supposedly 8% larger than that of the holotype specimen would rather have been 6.5% larger, or could simply have belonged to

6489-633: 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,

6592-416: The largest in the world. They conceded that comparison with Tyrannosaurus was difficult due to the disarticulated state of the cranial bones of Giganotosaurus , but noted that at 1.43 m (4.7 ft), the femur of Giganotosaurus was 5 cm (2 in) longer than that of " Sue ", the largest known Tyrannosaurus specimen, and that the bones of Giganotosaurus appeared to be more robust, indicating

6695-517: The largest predators, and would help in the understanding of Late Cretaceous dinosaur faunas, which had otherwise been very "North America-centric". In the same issue of the journal in which Carcharodontosaurus was described, the paleontologist Philip J. Currie cautioned that it was yet to be determined which of the two animals were larger, and that the size of an animal is less interesting to paleontologists than, for example, adaptations, relationships, and distribution. He also found it remarkable that

6798-416: The largest teeth in the premaxilla (front of the upper jaw) had pronounced wrinkles (with their highest relief near the serrations). The neck of Giganotosaurus was strong, and the axis bone (the neck vertebra that articulates with the skull) was robust. The rear neck (cervical) vertebrae had short, flattened centra (the "bodies" of the vertebrae), with almost hemispherical articulations (contacts) at

6901-435: The legs, skull, and pelvis. Other features showed that it was outside the more derived (or "advanced") clade Coelurosauria . In 1996, Sereno and colleagues found Giganotosaurus , Carcharodontosaurus , and Acrocanthosaurus to be closely related within the superfamily Allosauroidea , and grouped them in the family Carcharodontosauridae . Features shared between these genera include the lacrimal and postorbital bones forming

7004-431: 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. Postcranial The postcranium ("behind the cranium "; plural: postcrania ) or postcranial skeleton in zoology and vertebrate paleontology is the skeleton apart from the skull . The postcranium encompasses the axial skeleton , which includes

7107-402: The lower jaw may have been an adaptation for resisting tensile stress when the powerful bite was delivered with the front of the jaws against the prey. The first known fossils of the closely related Mapusaurus were found in a bonebed consisting of several individuals at different growth stages. In their 2006 description of the genus, Coria and Currie suggested that though this could be due to

7210-460: The lower side surfaces of the shelf. The neck muscles that elevated the head would have attached to the prominent supraoccipital bones on the top of the skull, which functioned like the nuchal crest of tyrannosaurs . A latex endocast of the brain cavity of Giganotosaurus showed that the brain was similar to that of the related genus Carcharodontosaurus , but larger. The endocast was 29 mm (1 in) long, 64 mm (3 in) wide, and had

7313-403: 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

7416-428: 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

7519-629: The northern and southern continents appear to have been severed by ocean barriers in the Late Cretaceous, which led to more distinct, provincial faunas, by preventing exchange. Previously, it was thought that the Cretaceous world was biogeographically separated, with the northern continents being dominated by tyrannosaurids, South America by abelisaurids , and Africa by carcharodontosaurids. The subfamily Carcharodontosaurinae, in which Giganotosaurus belongs, appears to have been restricted to

7622-424: The original measurement, and proposed that the body mass would have been smaller overall. In 2013, the paleontologist Scott Hartman published a Graphic Double Integration mass estimate (based on drawn skeletal reconstructions) on his blog, wherein he found Tyrannosaurus ("Sue") to have been larger than Giganotosaurus overall. He estimated the Giganotosaurus holotype to have weighed 6.8 t (7.5 short tons), and

7725-424: The power of their bite. In 2005 Therrien and colleagues estimated the relative bite force of theropods and found that Giganotosaurus and related taxa had adaptations for capturing and bringing down prey by delivering powerful bites, whereas tyrannosaurs had adaptations for resisting torsional stress and crushing bones. Estimates in absolute values like newtons were impossible. The bite force of Giganotosaurus

7828-541: 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

7931-471: The same strata as the single tooth and some sauropod dinosaurs that are also known from the same strata as Giganotosaurus . In 2001, the physician-scientist Frank Seebacher proposed a new polynomial method of calculating body-mass estimates for dinosaurs (using body-length, depth, and width), and found Giganotosaurus to have weighed 6.6 t (7.3 short tons) (based on the original 12.5 m (41 ft) length estimate). In their 2002 description of

8034-427: The skull length and body length ratio proposed by Therrien and Henderson and reconstructed various digital 3D models of theropods to measure body mass distribution and volume, resulting in the mass of a 13 m (43 ft) long Giganotosaurus up to 7.2 t (7.9 short tons). These researchers found the estimates consistent with the values proposed by previous studies. In 2022, Juan I. Canale and colleagues described

8137-412: The skull sideways in relation to the front neck vertebrae. These features may also have been related to the increased mass and length of the jaw muscles; the jaw articulation of Giganotosaurus and other carcharodontosaurids was moved hindwards to increase the length of the jaw musculature, enabling faster closure of the jaws, whereas tyrannosaurs increased the mass of the lower jaw musculature, to increase

8240-550: The skull to have been 1.60 m (5 ft) long, similar to Giganotosaurus , but perhaps exceeding that of the Tyrannosaurus "Sue", with a 1.53 m (5 ft) long skull. They also pointed out that carcharodontosaurs appear to have had the proportionally largest skulls, but that Tyrannosaurus appears to have had longer hind limbs. In an interview for a 1995 article entitled "new beast usurps T. rex as king carnivore", Sereno noted that these newly discovered theropods from South America and Africa competed with Tyrannosaurus as

8343-403: The smallest is 36 cm (14 in) long with a pace of 100 cm (39 in). The tracks are tridactyl (three-toed) and have large and coarse digits, with prominent claw impressions. Impressions of the digits occupy most of the track-length, and one track has a thin heel. Though the tracks were found in a higher stratigraphic level than the main fossils of Giganotosaurus , they were from

8446-539: The southern continent of Gondwana (formed by South America and Africa), where they were probably the apex (top) predators . The South American tribe Giganotosaurini may have been separated from their African relatives through vicariance , when Gondwana broke up during the Aptian – Albian ages of the Early Cretaceous. In 1999, the paleontologist Reese E. Barrick and the geologist William J. Showers found that

8549-497: 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,

8652-412: 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

8755-525: The strength of their leg-bones to be of limited value, since theropods, unlike birds, had heavy tails to counterbalance their weight. A 2017 biomechanical study of the running ability of Tyrannosaurus by the biologist William I. Sellers and colleagues suggested that skeletal loads were too great to have allowed adult individuals to run. The relatively long limbs, which were long argued to indicate good running ability, would instead have mechanically limited it to walking gaits, and it would therefore not have been

8858-403: 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

8961-475: The top rear of the skull. The jaw articulated far behind the occipital condyle (where the neck is attached to the skull) compared to other theropods. The condyle was broad and low, and had pneumatic cavities. Giganotosaurus did not have a sagittal crest on the top of the skull, and the jaw muscles did not extend onto the skull roof, unlike in most other theropods (due to the shelf over the supratemporal fenestrae). These muscles would instead have been attached to

9064-580: The turtle Prochelidella . Other vertebrates include cladotherian mammals, a pipoid frog, and ceratodontiform fishes. Footprints indicate the presence of large ornithopods and pterosaurs as well. [REDACTED] [REDACTED] [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

9167-413: The two animals were found within a year of each other, and were closely related, in spite of being found on different continents. In a 1997 interview, Coria estimated Giganotosaurus to have been 13.7 (45 ft) to 14.3 (47 ft) m long and weighing 8 to 10 t (8.8 to 11.0 short tons) based on new material, larger than Carcharodontosaurus . Sereno countered that it would be difficult to determine

9270-481: The upper biomechanical size limit attainable by a strictly bipedal animal. In 2010, the paleontologist Gregory S. Paul suggested that the skulls of carcharodontosaurs had been reconstructed as too long in general. In 2012, the paleontologist Matthew T. Carrano and colleagues noted that though Giganotosaurus had received much attention due to its enormous size, and in spite of the holotype being relatively complete, it had not yet been described in detail, apart from

9373-467: The upper jaw had a 92 cm (36 in) long tooth row, was deep from top to bottom, and its upper and lower edges were almost parallel. The maxilla had a pronounced process (projection) under the nostril, and a small, ellipse -shaped fenestra (opening), as in Allosaurus and Tyrannosaurus . The nasal bone was very rugose (rough and wrinkled), and these rugosities continued backwards, covering

9476-576: 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

9579-429: 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

9682-529: Was difficult to compare proportions between large theropod clades. In 2021, the paleontologist Matías Reolid and colleagues compiled various mass estimates of theropods (including Giganotosaurus ) to calculate the average, but did not include Therrien and Henderson's 2007 estimates of Carnotaurus and Giganotosaurus , considering them outliers. This resulted in a body mass range for Giganotosaurus between 5.5 and 8.5 t (6.1 and 9.4 short tons), with an average of 6.75 t (7.44 short tons). They also applied

9785-801: Was discovered in the Candeleros Formation , which was deposited during the Early Cenomanian age of the Late Cretaceous period, approximately 99.6 to 97 million years ago. This formation is the lowest unit in the Neuquén Group , wherein it is part of the Río Limay Subgroup . The formation is composed of coarse and medium-grained sandstones deposited in a fluvial environment (associated with rivers and streams), and in aeolian conditions (effected by wind). Paleosols (buried soil), siltstones , and claystones are present, some of which represent swamp conditions. Giganotosaurus

9888-429: Was discovered near Lake Ezequiel Ramos Mexia in 1987 by A. Delgado, and is therefore the first known fossil of the genus. Calvo further suggested that some theropod trackways and isolated tracks (which he made the basis of the ichnotaxon Abelichnus astigarrae in 1991) belonged to Giganotosaurus , based on their large size. The largest tracks are 50 cm (20 in) long with a pace of 130 cm (51 in), and

9991-416: Was named Giganotosaurus carolinii in 1995; the genus name translates to "giant southern lizard", and the specific name honors the discoverer, Ruben Carolini . A dentary bone , a tooth, and some tracks, discovered before the holotype, were later assigned to this animal. The genus attracted much interest and became part of a scientific debate about the maximum sizes of theropod dinosaurs. Giganotosaurus

10094-406: Was named, and it remained the largest known theropod dinosaur for 90 years, though other large theropods were also known. The discussion of which theropod was the largest was revived in the 1990s by new discoveries in Africa and South America . In their original description, Coria and Salgado considered Giganotosaurus at least the largest theropod dinosaur from the southern hemisphere , and perhaps

10197-412: Was one of the largest known terrestrial carnivores , but the exact size has been hard to determine due to the incompleteness of the remains found so far. Estimates for the most complete specimen range from a length of 12 to 13 m (39 to 43 ft), a skull 1.53 to 1.80 m (5.0 to 5.9 ft) in length, and a weight of 4.2 to 13.8 t (4.6 to 15.2 short tons). The dentary bone that belonged to

10300-463: Was probably the apex predator in its ecosystem. It shared its environment with herbivorous dinosaurs such as the titanosaurian sauropod Andesaurus , and the rebbachisaurid sauropods Limaysaurus and Nopcsaspondylus . Other theropods include the abelisaurid Ekrixinatosaurus , the dromaeosaurid Buitreraptor , and the alvarezsauroid Alnashetri . Other reptiles include the crocodyliform Araripesuchus , sphenodontians , snakes, and

10403-410: Was proportionally shorter than that of Tyrannosaurus , with the ratio between the scapula (shoulder blade) and the femur being less than 0.5. The blade of the scapula had parallel borders, and a strong tubercle for insertion of the triceps muscle . The coracoid was small and hook-shaped. The ilium of the pelvis had a convex upper border, a low postacetabular blade (behind the acetabulum ), and

10506-474: Was short. The fourth trochanter was large and projected backwards. The tibia of the lower leg was expanded at the upper end, its articular facet (where it articulated with the femur) was wide, and its shaft was compressed from front to back. Coria and Salgado originally found Giganotosaurus to group more closely with the theropod clade Tetanurae than to more basal (or "primitive") theropods such as ceratosaurs , due to shared features ( synapomorphies ) in

10609-447: Was weaker than that of Tyrannosaurus , and the force decreased hindwards along the tooth row. The lower jaws were adapted for slicing bites, and it probably captured and manipulated prey with the front part of the jaws. These authors suggested that Giganotosaurus and other allosaurs may have been generalized predators that fed on a wide spectrum of prey smaller than themselves, such as juvenile sauropods. The ventral process (or "chin") of

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