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102-685: Spinosaurus ( / ˌ s p aɪ n ə ˈ s ɔːr ə s / ; lit.   ' spine lizard ' ) is a genus of spinosaurid dinosaur that lived in what now is North Africa during the Cenomanian stage of the Late Cretaceous period , about 100 to 94  million years ago . The genus was known first from Egyptian remains discovered in 1912 and described by German palaeontologist Ernst Stromer in 1915 . The original remains were destroyed in World War II , but additional material came to light in

204-571: A carcharodontosaurid similar to Acrocanthosaurus and a dentary from Baryonyx or Suchomimus . The analysis was rejected in at least one subsequent paper. NMC 50791, held by the Canadian Museum of Nature , is a mid-cervical vertebra which is 19.5 centimeters (7.7 in) long from the Kem Kem Beds of Morocco . It is the holotype of Spinosaurus maroccanus, as described by Russell in 1996. Other specimens referred to S. maroccanus in

306-507: A sail-like structure , although some authors have suggested that the spines were covered in fat and formed a hump. The hip bones of Spinosaurus were reduced, and the legs were very short in proportion to the body. Its long and narrow tail was deepened by tall, thin neural spines and elongated chevrons , forming a flexible fin or paddle-like structure. Spinosaurus is known to have eaten fish, and most scientists believe that it hunted both terrestrial and aquatic prey. Evidence suggests that it

408-466: A 2007 paper using scaling based on skull length, challenged previous estimates of the size of Spinosaurus , finding the length too great and the weight too small. Based on estimated skull lengths of 1.5 to 1.75 m (4 ft 11 in to 5 ft 9 in), their estimates include a body length of 12.6 to 14.3 m (41 to 47 ft) and a body mass of 12 to 20.9 t (13.2 to 23.0 short tons). The lower estimates for Spinosaurus would imply that

510-543: A 2020 study on variation within Spinosaurus considers these differences in morphology to be indicative of variation in skull morphology within a single species, as is the case in Allosaurus. Some scientists have considered the genus Sigilmassasaurus a junior synonym of Spinosaurus . In Ibrahim and colleagues (2014), the specimens of Sigilmassasaurus was referred to Spinosaurus aegyptiacus together with "Spinosaurus B" as

612-512: A condition not observed in MSNM V4047 which has been referred to as a specimen of Spinosaurus , and thus adding a new possible diagnostic feature of Oxalaia . They also suggested that the premaxilla of Oxalaia is wider in the posterior portion than that of MSNM V4047, and that the lateral morphology of its rostrum was distinguished from other spinosaurines based on their morphometric analysis. In 2023, Isasmendi and colleagues considered Oxalaia as

714-465: A cooling wind, the animal would quite effectively cool itself in the warm climate of Cretaceous Africa. However, Bailey (1997) was of the opinion that a sail could have absorbed more heat than it radiated. Bailey proposed instead that Spinosaurus and other dinosaurs with long neural spines had fatty humps on their backs for energy storage, insulation, and shielding from heat. Many elaborate body structures of modern-day animals serve to attract members of

816-496: A distinct genus, though a very close relative of Spinosaurus , the two unified in the tribe Spinosaurini, coined in the study. The 2020 study indicates synonymy between Spinosaurus and Sigilmassasaurus , and considered specimens previously referred to Sigilmassasaurus as those of Spinosaurus . For instance, the referral of an isolated quadrate (specimen MHNM.KK376) to Sigilmassasaurus brevicollis , based on its difference from other specimens assigned to Spinosaurus aegyptiacus ,

918-465: A dorsal neural arch (SAM 128), belonged to S. maroccanus . Although it was originally ascribed to S. maroccanus , based on their examination of this cranial material, the 2016 study considered the difference between the two species to be not taxonomically significant and either ontogenetic or intraspecific, and thus tentatively assigned the specimen to S. aegyptiacus . The 2017 study considered MNHN SAM 124 to belong to same taxon as MSNM V4047. BM231 (in

1020-406: A hydrodynamic fulcrum and hydrodynamically stabilizing the trunk along the dorsoventral axis, Spinosaurus ’ sail would also have compensated for the inertia of the lateral neck by tail movements and vice versa not only for predation but also for accelerated swimming. This behavior might also have been one reason for Spinosaurus ’ muscular chest and neck reported by Ibrahim and colleagues (2014). It

1122-643: 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

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1224-621: 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,

1326-484: A maximum body length of 14 m (46 ft) and a maximum body mass of 7.4 t (8.2 short tons) by constructing a CT-based 3D skeletal model "with the axial column in neutral pose." They argued that the 2D graphical reconstruction of the aquatic hypothesis by Ibrahim and his colleagues in 2020 overestimated the presacral column length by 10%, ribcage depth by 25%, and forelimb length by 30% over dimensions based on CT-scanned fossils; these proportional overestimates shift

1428-409: 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

1530-453: A shoal of fish or squid, sailfish also raise their sails to make themselves appear larger. When they slash or wipe their bills through shoaling fish by turning their heads, their dorsal sail and fins are outstretched to stabilize their bodies hydrodynamically (Lauder & Drucker, 2004). Domenici and colleagues (2014) postulate that these fin extensions enhance the accuracy of tapping and slashing. The sail can reduce yaw rotation by counteracting

1632-411: A significantly smaller pelvis (hip bone) than that of other giant theropods, with the surface area of the ilium (main body of the pelvis) half that of most members of the clade. The hind limbs were short, at just over 25 percent of the total body length, with the tibia (calf bone) being longer than the femur (thigh bone). Unlike in other theropods, the hallux (or fourth toe) of Spinosaurus touched

1734-400: A space on the inside of the snout, the authors speculated that Spinosaurus had pressure receptors inside the space that allowed it to hold its snout at the surface of the water to detect swimming prey species without seeing them. A 2013 study by Andrew R. Cuff and Emily J. Rayfield concluded that bio-mechanical data suggests that Spinosaurus was not an obligate piscivore and that its diet

1836-509: A specimen of Spinosaurus . As a spinosaurid, Spinosaurus would have had a long, muscular neck, curved in a sigmoid , or S-shape. Its shoulders were prominent, and the forelimbs large and stocky, bearing three clawed digits on each hand. The first finger (or "thumb") would have been the largest. Spinosaurus had long phalanges (finger bones), and only somewhat recurved claws , suggesting that its hands were longer compared to those of other spinosaurids. Very tall neural spines growing on

1938-427: 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. ;

2040-455: 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

2142-522: A trait commonly observed in animals which have a semi-aquatic feeding habit. 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 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

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2244-486: A valid taxon based on the examination of its referred maxilla (MN 6119-V) which suggests that the position of its external naris would have been more anteriorly located, a condition similar to that of Irritator and baryonychines , differing from African spinosaurines including Spinosaurus aegyptiacus . Since its discovery, Spinosaurus has been a contender for the largest theropod dinosaur. Both Friedrich von Huene in 1926 and Donald F. Glut in 1982 listed it as among

2346-430: A wider distribution and supports the faunal exchange between South America and Africa during this time. However, subsequent studies have rejected the synonymy of Oxalaia with Spinosaurus aegyptiacus based on diagnostic features of the holotype (MN 6117-V) and the referred specimen (MN 6119-V). In 2021, Lacerda, Grillo and Romano noted that the anteromedial processes of the holotype maxillae (MN 6117-V) contact medially,

2448-480: Is a snout (consisting of partial premaxillae, partial maxillae, vomers , and a dentary fragment). Described by Taquet and Russell in 1998, the specimen is 13.4 to 13.6 centimeters (5.3–5.4 in) in width; no length was stated. The specimen was located in Algeria, and "is of Albian age." Taquet and Russell believed that the specimen, along with a premaxilla fragment (SAM 125), two cervical vertebrae (SAM 126–127), and

2550-596: 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

2652-542: Is known from oil exploration drilling across much of the Western Desert where it forms an important oil reservoir . The Bahariya Formation forms the base of the depression, the lower part of the enclosing escarpment and all of the small hills within. The type section for the formation is found at Gebel El-Dist, a hill at the northern end of the Bahariya depression. Four depositional sequences have been recognised in

2754-460: 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,

2856-613: Is stored in the Natural History Museum, London . FSAC-KK 11888 is a partial subadult skeleton recovered from the Kem Kem beds of North Africa. It was described by Ibrahim and colleagues in 2014 and designated as the neotype specimen, though Evers and colleagues rejected the neotype designation for FSAC-KK-11888 in 2015. It includes cervical vertebrae, dorsal vertebrae, neural spines, a complete sacrum, femora, tibiae, pedal phalanges, caudal vertebra, several dorsal ribs, and fragments of

2958-474: 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

3060-410: Is unclear whether Spinosaurus was primarily a terrestrial predator or a piscivore , as indicated by its elongated jaws, conical teeth and raised nostrils. The hypothesis of spinosaurs as specialized fish eaters has been suggested before by A. J. Charig and A. C. Milner for Baryonyx . They base this on the anatomical similarity with crocodilians and the presence of digestive acid-etched fish scales in

3162-621: 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

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3264-799: 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;

3366-507: The Kem Kem Group suggested the Brazilian spinosaurine Oxalaia to be a potential junior synonym of Spinosaurus aegyptiacus . This was based on looking at the specimens assigned to Oxalaia , and the supposed autapomorphies of this taxon to be insignificant and fall within the hypodigm of Spinosaurus aegyptiacus . If supported by future studies, this would imply Spinosaurus aegyptiacus had

3468-796: The Kem Kem beds in Morocco and Oxalaia from the Alcântara Formation in Brazil , though other researchers propose both genera to be distinct taxa . Spinosaurus is the longest known terrestrial carnivore ; other large carnivores comparable to Spinosaurus include theropods such as Tyrannosaurus , Giganotosaurus and Carcharodontosaurus . The most recent study suggests that previous body size estimates are overestimated, and that S. aegyptiacus reached 14 m (46 ft) in length and 7.4 t (8.2 short tons) in body mass. The skull of Spinosaurus

3570-503: The Museo di Storia Naturale di Milano ), described by Dal Sasso and colleagues in 2005 as Spinosaurus cf. S. aegyptiacus , consists of a snout (premaxillae, partial maxillae, and partial nasals) 98.8 centimeters (38.9 in) long from the Kem Kem Beds. An isolated fish vertebra, tentatively referred to Onchopristis , has been associated with the tooth alveolus of this specimen. Similarly,

3672-401: The Spinosaurus holotype specimen BSP 1912 VIII 19 discovered in the archives in 2000. On the basis of a photograph of the lower jaw and a photograph of the entire specimen as mounted, Smith concluded that Stromer's original 1915 drawings were slightly inaccurate. In 2003, Oliver Rauhut suggested that Stromer's Spinosaurus holotype was a chimera , composed of vertebrae and neural spines from

3774-694: The University of Chicago Paleontological Collection consists mainly of two narrow connected nasals with a fluted (ridged) crest from the region between the eyes. The specimen, which is 18.0 centimeters (7.1 in) long, was located in an early Cenomanian part of the Moroccan Kem Kem Beds in 1996 and described in the scientific literature in 2005 by Cristiano Dal Sasso of the Civic Natural History Museum in Milan and colleagues. MSNM V4047 (in

3876-417: The neotype and Spinosaurus maroccanus was considered as a nomen dubium following the conclusions of the other papers. A 2015 re-description of Sigilmassasaurus disputed these conclusions, and considered the genus valid, with inclusion of S. maroccanus as a synonym of Sigilmassasaurus instead. This conclusion was further supported in 2018 by Arden and colleagues, who consider Sigilmassasaurus to be

3978-419: 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 ,

4080-404: 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,

4182-741: The Bahariya Formation in the Bahariya depression, separated by three sub-aerial unconformities . The formation was deposited during a period of relative rise in sea level, with each unconformity representing a relative fall in sea level. Each of the individual sequences contains sediments deposited under fluvial , shoreline and shallow marine conditions. Direct fossils are sparse, though plant leaves with extensive damage from folivorous insects have been documented. In addition, there are isolated theropod teeth disputedly assigned to dromaeosaurids , or to abelisaurids . Thirty different genera are known from Bahariya, including megaflora . Much of

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4284-541: The Cenomanian age. Additionally, in 2024, a complete posterior cervical vertebra (specimen NHMUK PV R 38358) was assigned to Sigilmassasaurus brevicollis . Since the National Museum of Brazil fire in 2018 engulfed the palace housing the museum, with specimens of Oxalaia possibly being destroyed, any classification should remain tentative. In a 2020 paper written by Symth et al. in assessing spinosaurine specimens from

4386-457: The Kem Kem region of southeastern Morocco, provided by François Escuillié and are deposited in the collections of the Muséum d’Histoire Naturelle of Marrakech. Only MHNM.KK376 is assigned to Sigilmassasaurus brevicollis , while the other five specimens are assigned to S. aegyptiacus , since the quadrates show two different morphologies, suggesting the existence of two spinosaurines in Morocco. However,

4488-409: The advantage of more expeditions and material, it appears that they pertain either to Carcharodontosaurus or to Sigilmassasaurus . S. maroccanus was originally described by Dale Russell in 1996 as a new species based on the length of its neck vertebrae. Specifically, Russell claimed that the ratio of the length of the centrum (body of vertebra) to the height of the posterior articular facet

4590-683: The animal was shorter and lighter than Carcharodontosaurus and Giganotosaurus . The Therrien and Henderson study has been criticized for the choice of theropods used for comparison (e.g., most of the theropods used to set the initial equations were tyrannosaurids and carnosaurs , which have a different build than spinosaurids), and for the assumption that the Spinosaurus skull could be as little as 1.5 m (4 ft 11 in) in length. In 2014, Ibrahim and his colleagues suggested that Spinosaurus aegyptiacus could reach over 15 m (49 ft) in length. In 2022, however, Paul Sereno and his colleagues suggested that Spinosaurus aegyptiacus reached

4692-436: The back vertebrae of Spinosaurus formed the basis of what is usually called the animal's " sail ". The lengths of the neural spines reached over 10 times the diameters of the centra (vertebral bodies) from which they extended. The neural spines were slightly longer front to back at the base than higher up, and were unlike the thin rods seen in the pelycosaur finbacks Edaphosaurus and Dimetrodon , contrasting also with

4794-442: 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

4896-479: The center of mass anteriorly when translated to a flesh model, and thus the estimate from Ibrahim and his colleagues cannot be considered a reliable body size estimate. Its skull had a narrow snout filled with straight conical teeth that lacked serrations. There were six or seven teeth on each side of the very front of the upper jaw, in the premaxillae , and another twelve in both maxillae behind them. The second and third teeth on each side were noticeably larger than

4998-526: The collection of the Office National des Mines, Tunis) was described by Buffetaut and Ouaja in 2002. It consists of a partial anterior dentary 11.5 centimeters (4.5 in) in length from an early Albian stratum of the Chenini Formation of Tunisia . The dentary fragment, which included four alveoli and two partial teeth, was "extremely similar" to existing material of S. aegyptiacus . UCPC-2 in

5100-593: The complementary clade of all taxa closer to Baryonyx walkeri than to Spinosaurus aegyptiacus . Examinations by Marcos Sales, Cesar Schultz, and colleagues (2017) indicate that the South American spinosaurids Angaturama , Irritator , and Oxalaia were intermediate between Baronychinae and Spinosaurinae based on their craniodental features and cladistic analysis. This indicates that Baryonychinae may in fact be non-monophyletic. Their cladogram can be seen below. Baryonyx [REDACTED] The cladogram below depicts

5202-879: The condition observed in some other spinosaurids, though to a more extreme degree. Coupled with the also elongated chevron bones on the underside of the caudals, this resulted in a deep and narrow tail with a paddle or fin-like shape, comparable to the tails of newts and crocodilians . Spinosaurus gives its name to the dinosaur family Spinosauridae , which includes two subfamilies: Baryonychinae and Spinosaurinae. Baryonychinae includes Baryonyx from southern England and Suchomimus from Niger in central Africa . Spinosaurinae includes Spinosaurus , Siamosaurus , Ichthyovenator , Irritator , Angaturama (which may be synonymous with Irritator ), Sigilmassasaurus and Oxalaia (both of which may be synonymous with Spinosaurus ). The spinosaurines share unserrated straight teeth that are widely spaced (e.g., 12 on one side of

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5304-525: The dentary fragment of Spinosaurus aegyptiacus , MPDM 31, is associated with the rostral tooth of Onchopristis . Like UCPC-2, it is thought to have come from the early Cenomanian. Arden and colleagues in 2018 tentatively assigned this specimen to Sigilmassasaurus brevicollis given its size. However, this assignment was later rejected by other researchers who considered the uniqueness of this specimen to be based on misinterpretations and poor preservation of another specimen, NHMUK R16665, another snout stored that

5406-756: The disputed Spinosaurus maroccanus (meaning "Moroccan spine lizard"). The first described remains of Spinosaurus were found and described in the early 20th century. In 1912, Richard Markgraf discovered a partial skeleton of a giant theropod dinosaur in the Bahariya Formation of western Egypt. In 1915, German paleontologist Ernst Stromer published an article assigning the specimen to a new genus and species, Spinosaurus aegyptiacus . Fragmentary additional remains from Bahariya, including vertebrae and hindlimb bones, were designated by Stromer as " Spinosaurus B " in 1934. Stromer considered them different enough to belong to another species, and this has been borne out. With

5508-422: The dorsal neural spines formed a shape that was roughly rectangular, similar in shape to the dorsal fins of sailfish. They therefore argue that Spinosaurus used its dorsal neural sail in the same manner as sailfish, and that it also employed its long narrow tail to stun prey like a modern thresher shark . Sailfish employ their dorsal fins for herding schools of fish into a " bait ball " where they cooperate to trap

5610-436: The early 21st century. It is unclear whether one or two species are represented in the fossils reported in the scientific literature. The type species is S. aegyptiacus from Egypt and Morocco . Although a potential second dubious species, S. maroccanus , has been recovered from Morocco, this dubious species is likely a junior synonym of S. aegyptiacus . Other possible junior synonyms include Sigilmassasaurus from

5712-569: The fact that the median tubercle and median suture is present in BSPG 2011 I 115 but absent in FSAC-KK-18122, so the presence or absence of such feature should not be used to taxonomically separate isolated spinosaurid remains. Regardless of the synonymy of Sigilmassasaurus with Spinosaurus , some authors consider the possibility that there could be a second distinct spinosaurid in North Africa during

5814-484: The findings of Arden and colleagues (2018): Praia das Aguncheiras taxon Baryonyx walkeri [REDACTED] Eumeralla taxon Gara Samani taxon The function of the dinosaur's sail or hump is uncertain; scientists have proposed several hypotheses including heat regulation and display. In addition, such a prominent feature on its back could make it appear even larger than it was, intimidating other animals. The structure may have been used for thermoregulation . If

5916-404: The fish into a certain area where the sailfish can snatch the fish with their bills. The sail could have possibly reduced yaw rotation by counteracting the lateral force in the direction opposite to the slash as suggested by Gimsa and colleagues (2015). Spinosaurus anatomy exhibits another feature that may have a modern analogy: its long tail resembled that of the thresher shark, employed to slap

6018-446: 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

6120-417: The former too. In 2022, Sakamoto estimated that Spinosaurus had an anterior bite force of 4,829 newtons and a posterior bite force of 11,936 newtons. Based on this estimate, he asserted that the jaws of Spinosaurus are adapted for generating relatively faster shutting speeds with less muscle input force, indicating that the animal likely killed its prey with fast-snapping jaws rather than slow-crushing bites,

6222-410: The generic level. Six main partial specimens of Spinosaurus have been described. BSP 1912 VIII 19, described by Stromer in 1915 from the Bahariya Formation, was the holotype . The material consisted of the following items, most of which were incomplete: right and left dentaries and splenials from the lower jaw measuring 75 centimeters (30 in) long; a straight piece of the left maxilla that

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6324-727: 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,

6426-425: The ground, and the phalanges of the toe bones were unusually long and well-built. At their ends were shallow claws that had flat bottoms. This type of foot morphology is also seen in shorebirds , indicating that Spinosaurus 's feet evolved for walking across unstable substrate and that they may have been webbed . From the caudal vertebrae of the tail projected significantly elongated, thin neural spines, akin to

6528-628: 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,

6630-403: The lateral force in the direction opposite to the slash. This means that prey is less likely to recognize the massive trunk as being part of an approaching predator (Marras and colleagues, 2015; Webb & Weihs 2015). Spinosaurus exhibited the anatomical features required to combine all three hunting strategies: a sail for herding prey more efficiently, as well as flexible tail and neck to slap

6732-507: 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. Bahariya Formation The Bahariya Formation (also transcribed as Baharija Formation ) is a fossiliferous geologic formation dating back to the early Cenomanian , which outcrops within the Bahariya depression in Egypt , and

6834-489: The maxilla), as opposed to the baryonychines, which have serrated curved teeth that are numerous (e.g., 30 on one side of the maxilla). An analysis of Spinosauridae by Arden and colleagues (2018) named the clade Spinosaurini and defined it as all spinosaurids closer to Spinosaurus aegyptiacus than to Irritator challengeri or Oxalaia quilombensis ; it also found Siamosaurus suteethorni and Icthyovenator laosensis to be members of Spinosaurinae. The subfamily Spinosaurinae

6936-403: 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

7038-487: The most massive theropods in their surveys, at 15 m (49 ft) in length and upwards of 6 t (6.6 short tons) in weight. In 1988, Gregory S. Paul also listed it as the longest theropod at 15 m (49 ft), but gave a lower mass estimate of 4 t (4.4 short tons). In 2005, Dal Sasso and colleagues assumed that Spinosaurus and the related Suchomimus had the same body proportions in relation to their skull lengths, and thereby calculated that Spinosaurus

7140-428: 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

7242-546: The opposite sex during mating. It is possible that the sail of Spinosaurus was used for courtship, in a way similar to a peacock 's tail. Stromer speculated that the size of the neural spines may have differed between males and females. Gimsa and colleagues (2015) suggest that the dorsal sail of Spinosaurus was analogous to the dorsal fins of sailfish and served a hydrodynamic purpose. Gimsa and others point out that more basal, long-legged spinosaurids had otherwise round or crescent-shaped dorsal sails, whereas in Spinosaurus ,

7344-543: The postorbital part of the skull of MSNM V4047 had a shape similar to the postorbital part of the skull of Irritator , Dal Sasso and colleagues (2005) estimated that the skull of Spinosaurus was 1.75 meters (5.7 ft) long, but more recent estimates suggest a length of 1.6–1.68 meters (5.2–5.5 ft). The Dal Sasso and colleagues skull length estimate is questioned because skull shapes can vary across spinosaurid species and because MSNM V4047 may not belong to Spinosaurus itself, though recent studies have reconfirmed it as

7446-526: 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

7548-423: The relatively small ratio of surface area of their body compared to the overall volume ( Haldane's principle ), face far greater problems of dissipating excess heat at higher temperatures than gaining it at lower. Sails of large dinosaurs added considerably to the skin area of their bodies, with minimum increase of volume. Furthermore, if the sail was turned away from the sun, or positioned at a 90 degree angle towards

7650-403: The rest of the teeth in the premaxilla, creating a space between them and the large teeth in the front of the maxilla; large teeth in the lower jaw faced this space. The very tip of the snout holding those few large front teeth was expanded, and a small crest was present in front of the eyes. Using the dimensions of three specimens known as MSNM V4047, UCPC-2, and BSP 1912 VIII 19, and assuming that

7752-551: The rib cage of the type specimen . Large fish are known from the faunas containing other spinosaurids, including the Mawsonia , in the mid-Cretaceous of northern Africa and Brazil. Direct evidence for spinosaur diet comes from related European and South American taxa. Baryonyx was found with fish scales and bones from juvenile Iguanodon in its stomach, while a tooth embedded in a South American pterosaur bone suggests that spinosaurs occasionally preyed on pterosaurs, but Spinosaurus

7854-601: The sail of the Permian synapsid Dimetrodon , which lived before the dinosaurs even appeared, produced by convergent evolution . The structure may also have been more hump-like than sail-like, as noted by Stromer in 1915 ("one might rather think of the existence of a large hump of fat [ German : Fettbuckel ], to which the [neural spines] gave internal support") and by Jack Bowman Bailey in 1997. In support of his "buffalo-back" hypothesis, Bailey argued that in Spinosaurus , Ouranosaurus , and other dinosaurs with long neural spines,

7956-466: 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 the French botanist Joseph Pitton de Tournefort (1656–1708) is considered "the founder of the modern concept of genera". The scientific name (or

8058-538: The same paper were two other mid-cervical vertebrae (NMC 41768 and NMC 50790), an anterior dentary fragment (NMC 50832), a mid-dentary fragment (NMC 50833), and an anterior dorsal neural arch (NMC 50813). Russell stated that "only general locality information could be provided" for the specimen, and therefore it could be dated only "possibly" to the Albian. MNHN SAM 124, housed at the Muséum National d'Histoire Naturelle ,

8160-408: 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 a species : see Botanical name and Specific name (zoology) . The rules for the scientific names of organisms are laid down in

8262-686: The skull. The body proportions of the specimen have been debated, as the hind limbs are disproportionately shorter in the specimen than in previous reconstructions. However, it has been demonstrated by multiple paleontologists that the specimen is not a chimera, and is indeed a specimen of Spinosaurus that suggests that the animal had much smaller hind limbs than previously thought. Other known specimens consist mainly of very fragmentary remains and scattered teeth. These include: MHNM.KK374, MHNM.KK375, MHNM.KK376, MHNM.KK377, MHNM.KK378 and MSNM V6896 are six isolated quadrates (skull bones) of different sizes that were collected by locals and acquired commercially in

8364-498: The species as valid without much comment, most researchers regard S. maroccanus as a nomen dubium (dubious name) or as a junior synonym of S. aegyptiacus . Some studies have referred the holotype and other referred specimens of S. maroccanus (NMC 50791 and MNHN SAM 124-128) as S. cf. aegyptiacus . The specimens previously ascribed as paratypes of S. maroccanus (NMC 41768 and NMC 50790) are reidentified as indeterminate spinosaurid specimens that are currently not identifiable at

8466-497: 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,

8568-481: The spines were relatively shorter and thicker than the spines of pelycosaurs (which are known to have sails); instead, the dinosaurs' neural spines were similar to the neural spines of extinct hump-backed mammals such as Megacerops and Bison latifrons . In 2014, Ibrahim and colleagues instead posited that the spines were covered tightly by skin, similar to a crested chameleon , given their compactness, sharp edges, and likely poor blood flow . Spinosaurus had

8670-412: 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

8772-426: The structure contained abundant blood vessels, the animal could have used the sail's large surface area to absorb heat. This would imply that the animal was only partly warm-blooded at best and lived in climates where night-time temperatures were cool or low and the sky usually not cloudy. It is also possible that the structure was used to radiate excess heat from the body, rather than to collect it. Large animals, due to

8874-403: 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

8976-474: The thicker spines in the iguanodontian Ouranosaurus . Spinosaurus sails were unusual, although other dinosaurs, namely Ouranosaurus , which lived a few million years earlier in the same general region as Spinosaurus , and the Early Cretaceous South American sauropod Amargasaurus , might have developed similar structural adaptations of their vertebrae. The sail may be an analog of

9078-566: 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

9180-429: 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

9282-539: The water for stunning, injuring or killing prey. The submerged dorsal sail would have provided a strong centreboard-like counterforce for powerful sidewards movements of the strong neck and long tail, as performed by sailfish (Domenici and colleagues, 2014) or thresher sharks (Oliver and colleagues, 2013). While smaller dorsal sails or fins make the dorsal water volume better accessible for slashing, it can be speculated that their smaller stabilization effect makes lateral slashing less efficient (e.g. for thresher sharks). Forming

9384-451: The water to herd and stun shoals of fish before devouring them (Oliver and colleagues, 2013). The strategies that sailfish and thresher sharks employ against shoaling fish are more effective when the shoal is first concentrated into a ‘bait ball’ (Helfman, Collette & Facey, 1997; Oliver and colleagues, 2013; Domenici and colleagues, 2014). Since this is difficult for individual predators to achieve, they cooperate in this effort. When herding

9486-643: Was semiaquatic ; how capable it was of swimming has been strongly contested. Spinosaurus 's leg bones had osteosclerosis (high bone density), allowing for better buoyancy control. Multiple functions have been put forward for the dorsal sail, including thermoregulation and display ; either to intimidate rivals or attract mates. It lived in a humid environment of tidal flats and mangrove forests alongside many other dinosaurs, as well as fish, crocodylomorphs , lizards, turtles, pterosaurs , and plesiosaurs . Two species of Spinosaurus have been named: Spinosaurus aegyptiacus (meaning "Egyptian spine lizard") and

9588-430: Was 1.1 in S. aegyptiacus and 1.5 in S. maroccanus . Later authors have been split on this topic. Some authors note that the length of the vertebrae can vary from individual to individual, that the holotype specimen was destroyed and thus cannot be compared directly with the S. maroccanus specimen, and that it is unknown which cervical vertebrae the S. maroccanus specimens represent. Therefore, though some have retained

9690-531: Was 16 to 18 m (52 to 59 ft) in length and 7 to 9 t (7.7 to 9.9 short tons) in weight. The estimates were criticized because the skull length estimate was uncertain, and (assuming that body mass increases as the cube of body length) scaling Suchomimus, which was 11 m (36 ft) long and 3.8 t (4.2 short tons) in mass, to the range of estimated lengths of Spinosaurus would produce an estimated body mass of 11.7 to 16.7 t (12.9 to 18.4 short tons). François Therrien and Donald Henderson, in

9792-408: Was described but not drawn; 20 teeth; 2 cervical vertebrae; 7 dorsal (trunk) vertebrae; 3 sacral vertebrae; 1 caudal vertebra; 4 thoracic ribs; and gastralia . Of the nine neural spines whose heights are given, the longest ("i," associated with a dorsal vertebra) was 1.65 meters (5.4 ft) in length. Stromer claimed that the specimen was from the early Cenomanian, about 97 million years ago. It

9894-621: Was destroyed in World War II , specifically "during the night of 24/25 April 1944 in a British bombing raid of Munich" that severely damaged the building housing the Paläontologisches Museum München (Bavarian State Collection of Paleontology). However, detailed drawings and descriptions of the specimen remain. Stromer's son donated Stromer's archives to the Paläontologische Staatssammlung München in 1995, and Smith and colleagues analyzed two photographs of

9996-407: Was likely to have been a generalized and opportunistic predator, possibly a Cretaceous equivalent of large grizzly bears , being biased toward fishing, though it undoubtedly scavenged and took many kinds of small or medium-sized prey. In 2009, Dal Sasso and colleagues. reported the results of X-ray computed tomography of the MSNM V4047 snout. As the foramina on the outside all communicated with

10098-457: Was long, low, and narrow, similar to that of a modern crocodilian , and bore straight conical teeth with no serrations . It would have had large, robust forelimbs bearing three-fingered hands, with an enlarged claw on the first digit . The distinctive neural spines of Spinosaurus , which were long extensions of the vertebrae (or backbones), grew to at least 1.65 m (5.4 ft) long and were likely to have had skin connecting them, forming

10200-451: Was more closely associated with each individual's size. The characteristic rostral morphology of Spinosaurus allowed its jaws to resist bending in the vertical direction, but its jaws were poorly adapted with respect to resisting lateral bending compared to other members of this group ( Baryonyx ) and modern alligators. This suggests that Spinosaurus preyed more regularly on fish than it did on land animals, although considered predators of

10302-428: Was named by Sereno in 1998, and defined by Holtz and colleagues (2004) as all taxa closer to Spinosaurus aegyptiacus than to Baryonyx walkeri . The subfamily Baryonychinae was named by Charig & Milner in 1986. They erected both the subfamily and the family Baryonychidae for the newly discovered Baryonyx , before it was referred to Spinosauridae. Their subfamily was defined by Holtz and colleagues in 2004, as

10404-407: Was rejected by the 2020 study which noted that these differences in morphology are indicative of variation in skull morphology within a single species. The 2019 study assigned a juvenile specimen FSAC-KK-18122 to Sigilmassasaurus brevicollis based on its identical proportion to BSPG 2011 I 115 which was assigned to the taxon in a 2015 study, but this referral was also rejected in a 2020 study based on

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