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106-408: Smilodon is an extinct genus of felids . It is one of the best known saber-toothed predators and prehistoric mammals. Although commonly known as the saber-toothed tiger , it was not closely related to the tiger or other modern cats, belonging to the extinct subfamily Machairodontinae , with an estimated date of divergence from the ancestor of living cats around 20 million years ago. Smilodon
212-453: A Smilodon suffering hip dysplasia at a young age that survived to adulthood suggests that it could not have survived to adulthood without aid from a social group, as this individual was unable to hunt or defend its territory due to the severity of its congenital issue. The brain of Smilodon was relatively small compared to other cat species. Some researchers have argued that Smilodon 's brain would have been too small for it to have been
318-475: A nimravid ("false sabertooth cat"), according to analysis of tooth puncture marks on a fossil Dinictis skull found in North Dakota. Zigzag Hunter–Schreger bands in the enamel indicate that bone was a significant component of the diet of Hyaenodon . In North America the last Hyaenodon , in the form of H. brevirostrus , disappeared in the late Oligocene . In Europe, they had already vanished earlier in
424-455: A folded orbicularis oris muscle , and such a muscle arrangement exists in modern large felids. Antón stated that extant phylogenetic bracketing (where the features of the closest extant relatives of a fossil taxon are used as reference) is the most reliable way of restoring the life-appearance of prehistoric animals, and the cat-like Smilodon restorations by Knight are therefore still accurate. A 2022 study by Antón and colleagues concluded that
530-434: A general rule that the saber-toothed cats with the largest canines had proportionally weaker bites. Analyses of canine bending strength (the ability of the canine teeth to resist bending forces without breaking) and bite forces indicate that the saber-toothed cats' teeth were stronger relative to the bite force than those of modern big cats. In addition, Smilodon 's gape could have reached over 110 degrees, while that of
636-523: A hindrance when feeding. A study published in 2022 of how machairodonts fed revealed that wear patterns on the teeth of S. fatalis also suggest that it was capable of eating bone to a similar extent as lions. This and comparisons with bite marks left by the contemporary machairodont Xenosmilus suggest that Smilodon and its relatives could efficiently de-flesh a carcass of meat when feeding without being hindered by their long canines. Despite being more powerfully built than other large cats, Smilodon had
742-643: 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
848-455: A long tail. Compared to the larger (but not closely related) Hyainailouros , the dentition of Hyaenodon was geared more towards shearing meat and less towards bone crushing. Some species of this genus were among the largest terrestrial carnivorous mammals of their time; others were only of the size of a marten . Remains of many species are known from North America, Europe, and Asia. The average weight of adult or subadult H. horridus ,
954-621: 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,
1060-422: A more lion-like clamping bite as its primary means of attacking prey. The discovery, made by Figueirido and Lautenschlager et al., published in 2018 suggests extremely different ecological adaptations in both machairodonts. The mandibular flanges may have helped resist bending forces when the mandible was pulled against the hide of a prey animal. It has been experimentally proven by means of a machine that recreates
1166-412: A reduced lumbar region , high scapula , short tail, and broad limbs with relatively short feet. Smilodon is most famous for its relatively long canine teeth, which are the longest found in the saber-toothed cats, at about 28 cm (11 in) long in the largest species, S. populator . The canines were slender and had fine serrations on the front and back side. The skull was robustly proportioned and
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#17328480619801272-409: 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
1378-701: A shoulder height of 100 cm (39 in) and body length of 175 cm (69 in). It was similar to a lion in dimensions, but was more robust and muscular, and therefore had a larger body mass. Its skull was also similar to that of Megantereon , though more massive and with larger canines. S. populator was among the largest known felids , with a body mass range from 220 kg (490 lb) to over 400 kg (880 lb), and one estimate suggesting up to 470 kg (1,040 lb). A particularly large S. populator skull from Uruguay measuring 39.2 cm (15.4 in) in length indicates this individual may have weighed as much as 436 kg (961 lb). It stood at
1484-549: A shoulder height of 120 cm (47 in). Compared to S. fatalis , S. populator was more robust and had a more elongated and narrow skull with a straighter upper profile, higher positioned nasal bones , a more vertical occiput , more massive metapodials and slightly longer forelimbs relative to hindlimbs. Large fossil tracks from Argentina (for which the ichnotaxon name Smilodonichium has been proposed) have been attributed to S. populator , and measure 17.6 cm (6.9 in) by 19.2 cm (7.6 in). This
1590-553: A similar scenario, and have also produced fossils of Smilodon . Unlike in La Brea, many of the bones were broken or show signs of weathering. This may have been because the layers were shallower, so the thrashing of trapped animals damaged the bones of previously trapped animals. Many of the carnivores at Talara were juveniles, possibly indicating that inexperienced and less fit animals had a greater chance of being trapped. Though Lund thought accumulations of Smilodon and herbivore fossils in
1696-428: A social animal. An analysis of brain size in living big cats found no correlation between brain size and sociality. Another argument against Smilodon being social is that being an ambush hunter in closed habitat would likely have made group-living unnecessary, as in most modern cats. Yet it has also been proposed that being the largest predator in an environment comparable to the savanna of Africa, Smilodon may have had
1802-628: A social structure similar to modern lions, which possibly live in groups primarily to defend optimal territory from other lions (lions are the only social big cats today). Whether Smilodon was sexually dimorphic has implications for its reproductive behavior. Based on their conclusions that Smilodon fatalis had no sexual dimorphism, Van Valkenburgh and Sacco suggested in 2002 that, if the cats were social, they would likely have lived in monogamous pairs (along with offspring) with no intense competition among males for females. Likewise, Meachen-Samuels and Binder concluded in 2010 that aggression between males
1908-511: A statistical study of the correlation between canine and body size in S. populator found no difference in scaling between body and canine size concluded it was more likely they evolved solely for a predatory function. Genus Genus ( / ˈ dʒ iː n ə s / ; pl. : genera / ˈ dʒ ɛ n ər ə / ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses . In binomial nomenclature ,
2014-495: A straight line across. The p3 premolar tooth of the mandible was present in most early specimens, but lost in later specimens; it was only present in 6% of the La Brea sample. There is some dispute over whether Smilodon was sexually dimorphic . Some studies of S. fatalis fossils have found little difference between the sexes. Conversely, a 2012 study found that, while fossils of S. fatalis show less variation in size among individuals than modern Panthera , they do appear to show
2120-427: 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. ;
2226-455: 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
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#17328480619802332-486: A typical cat and similar to a bulldog , with a lower lip line (to allow its mouth to open wide without tearing the facial tissues), a more retracted nose and lower-placed ears. Paleoartist Mauricio Antón and coauthors disputed this in 1998 and maintained that the facial features of Smilodon were overall not very different from those of other cats. Antón noted that modern animals like the hippopotamus are able to open their mouths extremely wide without tearing tissue due to
2438-470: A weaker bite. Modern big cats have more pronounced zygomatic arches , while these were smaller in Smilodon , which restricted the thickness and therefore power of the temporalis muscles and thus reduced Smilodon ' s bite force. Analysis of its narrow jaws indicates that it could produce a bite only a third as strong as that of a lion (the bite force quotient measured for the lion is 112). There seems to be
2544-585: Is S. gracilis , which existed from 2.5 million to 500,000 years ago (early Blancan to Irvingtonian ages) and was the successor in North America of Megantereon , from which it probably evolved. Megantereon itself had entered North America from Eurasia during the Pliocene , along with Homotherium . S. gracilis reached the northern regions of South America in the Early Pleistocene as part of
2650-596: 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
2756-584: Is larger than tracks of the Bengal tiger , to which the footprints have been compared. Smilodon and other saber-toothed cats have been reconstructed with both plain-colored coats and with spotted patterns (which appears to be the ancestral condition for feliforms ), both of which are considered possible. Studies of modern cat species have found that species that live in the open tend to have uniform coats while those that live in more vegetated habitats have more markings, with some exceptions. Some coat features, such as
2862-460: 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,
2968-534: Is still one of the best-known members of the group, to the point where the two concepts have been confused. The term " saber-tooth " itself refers to an ecomorph consisting of various groups of extinct predatory synapsids (mammals and close relatives), which convergently evolved extremely long maxillary canines , as well as adaptations to the skull and skeleton related to their use. This includes members of Gorgonopsia , Thylacosmilidae , Machaeroidinae , Nimravidae , Barbourofelidae , and Machairodontinae . Within
3074-443: Is that the cat delivered a deep stabbing bite or open-jawed stabbing thrust to the throat, killing the prey very quickly. Another hypothesis suggests that Smilodon targeted the belly of its prey. This is disputed, as the curvature of their prey's belly would likely have prevented the cat from getting a good bite or stab. In regard to how Smilodon delivered its bite, the "canine shear-bite" hypothesis has been favored, where flexion of
3180-474: 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
3286-519: Is thought to have killed its prey by holding it still with its forelimbs and biting it, but it is unclear in what manner the bite itself was delivered. Scientists debate whether Smilodon had a social or a solitary lifestyle; analysis of modern predator behavior as well as of Smilodon ' s fossil remains could be construed to lend support to either view. Smilodon probably lived in closed habitats such as forests and bush , which would have provided cover for ambushing prey. Smilodon died out as part of
Smilodon - Misplaced Pages Continue
3392-546: The Ancient Greek meaning of Smilodon as σμίλη ( smilē ), "scalpel" or "two-edged knife", and οδόντος ( odóntos ), "tooth". This has also been translated as "tooth shaped like double-edged knife". He explained the species name populator as "the destroyer", which has also been translated as "he who brings devastation". Lund based the name on the shape of the incisors, and the large canine teeth were not known until 1846. By 1846, Lund had acquired nearly every part of
3498-583: The F. fatalis molar was identical to that of Smilodon , and he proposed the new combination S. fatalis . Most North American finds were scanty until excavations began in the La Brea Tar Pits in Los Angeles , where hundreds of individuals of S. fatalis have been found since 1875. S. fatalis has junior synonyms such as S. mercerii , S. floridanus , and S. californicus . American paleontologist Annalisa Berta considered
3604-482: The Great American Interchange . S. fatalis existed 1.6 million–10,000 years ago (late Irvingtonian to Rancholabrean ages), and replaced S. gracilis in North America. S. populator existed 1 million–10,000 years ago ( Ensenadan to Lujanian ages); it occurred in the eastern parts of South America. Smilodon was around the size of modern big cats , but was more robustly built. It had
3710-621: 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
3816-799: 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;
3922-403: The La Brea Tar Pits in Los Angeles constitute the largest collection of Smilodon fossils. Overall, Smilodon was more robustly built than any extant cat, with particularly well-developed forelimbs and exceptionally long upper canine teeth . Its jaw had a bigger gape than that of modern cats, and its upper canines were slender and fragile, being adapted for precision killing. S. gracilis
4028-501: The Oligocene of Europe, such as Proailurus , and the earliest one with saber-tooth features is the Miocene genus Pseudaelurus . The skull and mandible morphology of the earliest saber-toothed cats was similar to that of the modern clouded leopards ( Neofelis ). The lineage further adapted to the precision killing of large animals by developing elongated canine teeth and wider gapes, in
4134-484: The distress calls of prey than solitary species. Since S. fatalis fossils are common at the La Brea Tar Pits, and were likely attracted by the distress calls of stuck prey, this could mean that this species was social as well. One critical study claims that the study neglects other factors, such as body mass (heavier animals are more likely to get stuck than lighter ones), intelligence (some social animals, like
4240-467: The end-Pleistocene extinction event around 13-10,000 years ago, along with most other large animals across the Americas. Its reliance on large animals has been proposed as the cause of its extinction. Smilodon may have been impacted by habitat turnover and loss of prey it specialized on due to possible climatic impacts, the effects of recently arrived humans on prey populations, and other factors. During
4346-419: The muzzle was short and broad. The cheek bones (zygomata) were deep and widely arched, the sagittal crest was prominent, and the frontal region was slightly convex. The mandible had a flange on each side of the front. The upper incisors were large, sharp, and slanted forwards. There was a diastema (gap) between the incisors and molars of the mandible. The lower incisors were broad, recurved, and placed in
Smilodon - Misplaced Pages Continue
4452-419: 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 ,
4558-404: 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,
4664-414: The 1830s, Danish naturalist Peter Wilhelm Lund and his assistants collected fossils in the calcareous caves near the small town of Lagoa Santa, Minas Gerais , Brazil. Among the thousands of fossils found, he recognized a few isolated cheek teeth as belonging to a hyena , which he named Hyaena neogaea in 1839. After more material was found (including incisor teeth and foot bones), Lund concluded
4770-527: The American lion, may have avoided the tar because they were better able to recognize the hazard), lack of visual and olfactory lures, the type of audio lure, and the length of the distress calls (the actual distress calls of the trapped prey animals would have lasted longer than the calls used in the study). The author of that study ponders what predators would have responded if the recordings were played in India, where
4876-505: The Lagoa Santa Caves were due to the cats using the caves as dens, these are probably the result of animals dying on the surface, and water currents subsequently dragging their bones to the floor of the cave, but some individuals may also have died after becoming lost in the caves. Scientists debate whether Smilodon was social . One study of African predators found that social predators like lions and spotted hyenas respond more to
4982-1174: The Machairodontinae diverged early from the ancestors of living cats and were not closely related to any living species. The ancestors of living cats and Machairodontinae estimated to have diverged around 20 million years ago. The following cladogram based on fossils and DNA analysis shows the placement of Smilodon among extinct and extant felids, after Rincón and colleagues, 2011: Proailurus Pseudaelurus Panthera (tigers, lions, jaguars, and leopards) [REDACTED] Caracal [REDACTED] Leopardus ( ocelot and relatives) [REDACTED] Felis ( domestic cats and relatives) [REDACTED] Herpailurus (jaguarundi) [REDACTED] Miracinonyx [REDACTED] Puma (cougar) [REDACTED] Dinofelis [REDACTED] Nimravides Machairodus [REDACTED] Homotherium [REDACTED] Xenosmilus [REDACTED] Paramachairodus Megantereon Smilodon gracilis [REDACTED] Smilodon populator [REDACTED] Smilodon fatalis [REDACTED] The earliest felids are known from
5088-451: The North and South American species may be due to the difference in prey between the two continents. Smilodon may have avoided eating bone and would have left enough food for scavengers. Coprolites assigned to S. populator recovered from Argentina preserve osteoderms from the ground sloth Mylodon and a Lama scaphoid bone. In addition to this unambiguous evidence of bone consumption,
5194-442: 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
5300-482: The camel like litoptern ungulate Macrauchenia , the rhinoceros-like ungulate Toxodon platensis , the large armadillo relatives Pachyarmatherium , Holmesina , species of the glyptodont genus Panochthus , the llama Palaeolama , the ground sloth Catonyx , and the equine Equus neogeus , and the crocodilian Caiman latirostris . This analysis of its diet also indicates that S. populator hunted both in open and forested habitats. The differences between
5406-463: The canine crown and the gum was enlarged, which helped stabilize the tooth and helped the cat sense when the tooth had penetrated to its maximum extent. Since saber-toothed cats generally had a relatively large infraorbital foramen (opening) in the skull, which housed nerves associated with the whiskers, it has been suggested the improved senses would have helped the cats' precision when biting outside their field of vision, and thereby prevent breakage of
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#17328480619805512-468: The canine to be distinct from that of the other Smilodon species due to its smaller size and more compressed base. Its specific name refers to the species' lighter build. This species is known from fewer and less complete remains than the other members of the genus. S. gracilis has at times been considered part of genera such as Megantereon and Ischyrosmilus . S. populator , S. fatalis and S. gracilis are currently considered
5618-431: The canines of another Smilodon (though it cannot be ruled out they were caused by kicking prey). If caused by intraspecific fighting, it may also indicate that they had social behavior which could lead to death, as seen in some modern felines (as well as indicating that the canines could penetrate bone). It has been suggested that the exaggerated canines of saber-toothed cats evolved for sexual display and competition, but
5724-423: The canines. The blade-like carnassial teeth were used to cut skin to access the meat, and the reduced molars suggest that they were less adapted for crushing bones than modern cats. As the food of modern cats enters the mouth through the side while cutting with the carnassials, not the front incisors between the canines, the animals do not need to gape widely, so the canines of Smilodon would likewise not have been
5830-425: The colloquial name "saber-toothed tiger", Smilodon is not closely related to the modern tiger (which belongs in the subfamily Pantherinae ), or any other extant felid. A 1992 ancient DNA analysis suggested that Smilodon should be grouped with modern cats (subfamilies Felinae and Pantherinae). A 2005 study found that Smilodon belonged to a separate lineage. A study published in 2006 confirmed this, showing that
5936-591: The coprolites suggest that Smilodon had a more generalist diet than previously thought. Examinations of dental microwear from La Brea further suggests that Smilodon consumed both flesh and bone. Smilodon itself may have scavenged dire wolf kills. It has been suggested that Smilodon was a pure scavenger that used its canines for display to assert dominance over carcasses, but this theory is not supported today as no modern terrestrial mammals are pure scavengers. The brain of Smilodon had sulcal patterns similar to modern cats, which suggests an increased complexity of
6042-517: The course of the Pleistocene, by the Late Pleistocene , only two genera of machairodonts remained, Smilodon , and the distantly related Homotherium , both largely confined to the Americas. Based on mitochondrial DNA sequences extracted from ancient bones , the lineages of Homotherium and Smilodon are estimated to have diverged about 18 million years ago. The earliest species of Smilodon
6148-613: The dire wolves' preferences for prey inhabiting open areas such as grassland. The availability of prey in the Rancho La Brea area was likely comparable to modern East Africa . As Smilodon migrated to South America, its diet changed; bison were absent, the horses and proboscideans were different, and native ungulates such as toxodonts and litopterns were completely unfamiliar, yet S. populator thrived as well there as its relatives in North America. Isotopic analysis for S. populator suggests that its main prey species included
6254-501: The extinct American lion. The humerus cortical wall in S. fatalis was a 15 % thicker than excpected in modern big cats of similar size. The thickening of S. fatalis femurs was within the range of extant felids. Its canines were fragile and could not have bitten into bone; due to the risk of breaking, these cats had to subdue and restrain their prey with their powerful forelimbs before they could use their canine teeth, and likely used quick slashing or stabbing bites rather than
6360-694: The family Felidae (true cats), members of the subfamily Machairodontinae are referred to as saber-toothed cats, and this group is itself divided into three tribes : Metailurini (false saber-tooths); Homotherini ( scimitar -toothed cats); and Smilodontini ( dirk -toothed cats), to which Smilodon belongs. Members of Smilodontini are defined by their long slender canines with fine to no serrations , whereas Homotherini are typified by shorter, broad, and more flattened canines, with coarser serrations. Members of Metailurini were less specialized and had shorter, less flattened canines, and are not recognized as members of Machairodontinae by some researchers. Despite
6466-646: The first upper molar. The various species of Hyaenodon competed with each other and with other hyaenodont genera (including Sinopa , Dissopsalis and Hyainailurus ), and played important roles as predators in ecological communities as late as the Miocene in Asia and preyed on a variety of prey species such as primitive horses like Mesohippus , Brontotheres , early camels, oreodonts and even primitive rhinos. Species of Hyaenodon have been shown to have successfully preyed on other large carnivores of their time, including
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#17328480619806572-446: 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
6678-411: The fossils instead belonged to a distinct genus of felids, though transitional to the hyenas. He stated it would have matched the largest modern predators in size, and was more robust than any modern cat. Lund originally wanted to call the new genus Hyaenodon , but realizing this name had recently been applied to another prehistoric predator, he instead named it Smilodon populator in 1842. He explained
6784-727: 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,
6890-528: The genus name forms the first part of the binomial species name for each species within the 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
6996-509: The hindlimbs, and was probably an ambush predator. The heel bone of Smilodon was fairly long, which suggests it was a good jumper. Its well-developed flexor and extensor muscles in its forearms probably enabled it to pull down, and securely hold down, large prey. Analysis of the cross-sections of S. fatalis humeri indicated that they were strengthened by cortical thickening to such an extent that they would have been able to sustain greater loading than those of extant big cats, or of
7102-434: The holotype of S. fatalis too incomplete to be an adequate type specimen, and the species has at times been proposed to be a junior synonym of S. populator . Nordic paleontologists Björn Kurtén and Lars Werdelin supported the distinctness of the two species in an article published in 1990. A 2018 article by the American paleontologist John P. Babiarz and colleagues concluded that S. californicus , represented by
7208-415: The largest North American species, is estimated to about 40 kg (88 lb) and may not have exceeded 60 kg (130 lb). H. gigas , the largest Hyaenodon species, was much larger, being 378 kg (833 lb) and around 10 ft (3 m). H. crucians from the early Oligocene of North America is estimated to only 10 to 25 kg (22 to 55 lb). H. microdon and H. mustelinus from
7314-460: The largest collection in the world. The sediments of the pits there were accumulated 40,000 to 10,000 years ago, in the Late Pleistocene . Though the trapped animals were buried quickly, predators often managed to remove limb bones from them, but they were themselves often trapped and then scavenged by other predators; 90% of the excavated bones belonged to predators. The Talara Tar Seeps in Peru represent
7420-628: 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,
7526-457: The late Eocene of North America were even smaller and weighed probably about 5 kg (11 lb). Studies on juvenile Hyaenodon specimens show that the animal had a very unusual system of tooth replacement. Juveniles took about 3–4 years to complete the final stage of eruption, implying a long adolescent phase. In North American forms, the first upper premolar erupts before the first upper molar, while European forms show an earlier eruption of
7632-504: 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. Hyaenodon Hyaenodon (" hyena -tooth") is an extinct genus of carnivorous placental mammals from extinct tribe Hyaenodontini within extinct subfamily Hyaenodontinae (in extinct family Hyaenodontidae ), that lived in Eurasia and North America from
7738-446: The manes of male lions or the stripes of the tiger, are too unusual to predict from fossils. Traditionally, saber-toothed cats have been artistically restored with external features similar to those of extant felids, by artists such as Charles R. Knight in collaboration with various paleontologists in the early 20th century. In 1969, paleontologist G. J. Miller instead proposed that Smilodon would have looked very different from
7844-410: The middle Eocene , throughout the Oligocene , to the early Miocene . Typical of early carnivorous mammals, individuals of Hyaenodon had a very massive skull , but a small brain . The skull is long with a narrow snout—much larger in relation to the length of the skull than in canine carnivores, for instance. The neck was shorter than the skull, while the body was long and robust and terminated in
7950-468: The modern American bison ) and camels ( Camelops ) were most commonly taken by the cats there. Smilodon fatalis may have also occasionally preyed upon Glyptotherium , based on a skull from a juvenile Glyptotherium texanum recovered from Pleistocene deposits in Arizona that bear the distinctive elliptical puncture marks best matching those of Smilodon , indicating that the predator successfully bit into
8056-621: The modern lion reaches 65 degrees. This made the gape wide enough to allow Smilodon to grasp large prey despite the long canines. A 2018 study compared the killing behavior of Smilodon fatalis and Homotherium serum , and found that the former had a strong skull with little trabecular bone for a stabbing canine-shear bite, whereas the latter had more trabecular bone and used a clamp and hold style more similar to lions. The two would therefore have held distinct ecological niches. By finding of correlation between relative cribriform plate size and repertoire of functional olfactory receptor genes, it
8162-403: 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
8268-428: 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
8374-413: The neck and rotation of the skull assisted in biting the prey, but this may be mechanically impossible. However, evidence from comparisons with Homotherium suggest that Smilodon was fully capable of and utilized the canine shear-bite as its primary means of killing prey, based on the fact that it had a thick skull and relatively little trabecular bone, while Homotherium had both more trabecular bone and
8480-399: The only valid species of Smilodon , and features used to define most of their junior synonyms have been dismissed as variation between individuals of the same species (intraspecific variation). One of the most famous of prehistoric mammals, Smilodon has often been featured in popular media and is the state fossil of California. Long the most completely known saber-toothed cat , Smilodon
8586-439: The otherwise solitary tigers are known to aggregate around a single carcass. The authors of the original study responded that though effects of the calls in the tar pits and the playback experiments would not be identical, this would not be enough to overturn their conclusions. In addition, they stated that weight and intelligence would not likely affect the results as lighter carnivores are far more numerous than heavy herbivores and
8692-456: The process sacrificing high bite force . As their canines became longer, the bodies of the cats became more robust for immobilizing prey. In derived smilodontins and homotherins, the lumbar region of the spine and the tail became shortened, as did the hind limbs. Machairodonts once represented a dominant group of felids distributed across Africa, Eurasia and the North America during the Miocene and Pliocene epochs, but progressively declined over
8798-526: 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
8904-525: The regions that control the sense of hearing, sight, and coordination of the limbs. Felid saber-tooths in general had relatively small eyes that were not as forward-facing as those of modern cats, which have good binocular vision to help them move in trees. Smilodon was likely an ambush predator that concealed itself in dense vegetation, as its limb proportions were similar to modern forest-dwelling cats, and its short tail would not have helped it balance while running. Unlike its ancestor Megantereon , which
9010-476: The same difference between the sexes in some traits. S. gracilis was the smallest species, estimated at 55 to 100 kg (121 to 220 lb) in weight, about the size of a jaguar . It was similar to its predecessor Megantereon of the same size, but its dentition and skull were more advanced, approaching S. fatalis . S. fatalis was intermediate in size between S. gracilis and S. populator . It ranged from 160 to 280 kg (350 to 620 lb). and reached
9116-466: 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
9222-408: 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
9328-618: The second half of the 19th century onwards. In 1869, American paleontologist Joseph Leidy described a maxilla fragment with a molar , which had been discovered in a petroleum bed in Hardin County, Texas . He referred the specimen to the genus Felis (which was then used for most cats, extant as well as extinct) but found it distinct enough to be part of its own subgenus , as F. ( Trucifelis ) fatalis . The species name means "deadly". In an 1880 article about extinct American cats, American paleontologist Edward Drinker Cope pointed out that
9434-721: The skeleton (from different individuals), and more specimens were found in neighboring countries by other collectors in the following years. Though some later authors used Lund's original species name neogaea instead of populator , it is now considered an invalid nomen nudum , as it was not accompanied with a proper description and no type specimens were designated. Some South American specimens have been referred to other genera, subgenera, species, and subspecies , such as Smilodontidion riggii , Smilodon ( Prosmilodon ) ensenadensis , and S. bonaeriensis , but these are now thought to be junior synonyms of S. populator . Fossils of Smilodon were discovered in North America from
9540-837: The skull through the glyptodont's armored cephalic shield. In addition, isotopes preserved in the tooth enamel of S. gracilis specimens from Florida show that this species fed on the peccary Platygonus and the llama -like Hemiauchenia . Stable carbon isotope measurements of S. gracilis remains in Florida varied significantly between different sites and show that the species was flexible in its feeding habits. Isotopic studies of dire wolf ( Aenocyon dirus ) and American lion ( Panthera atrox ) bones show an overlap with S. fatalis in prey, which suggests that they were competitors. More detailed isotope analysis however, indicates that Smilodon fatalis preferred forest-dwelling prey such as tapirs, deer and forest-dwelling bison as opposed to
9646-401: The slow, suffocating bites typically used by modern cats. On rare occasions, as evidenced by fossils, Smilodon was willing to risk biting into bone with its canines. This may have been focused more towards competition such as other Smilodon or potential threats such as other carnivores than on prey. Debate continues as to how Smilodon killed its prey. Traditionally, the most popular theory
9752-412: The social (and seemingly intelligent) dire wolf is also found in the pits. Another argument for sociality is based on the healed injuries in several Smilodon fossils, which would suggest that the animals needed others to provide them food. This argument has been questioned, as cats can recover quickly from even severe bone damage and an injured Smilodon could survive if it had access to water. However,
9858-497: 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,
9964-595: The specimens from the La Brea Tar Pits, was a distinct species from S. fatalis after all and that more research is needed to clarify the taxonomy of the lineage. In his 1880 article about extinct cats, Cope also named a third species of Smilodon , S. gracilis . The species was based on a partial canine, which had been obtained in the Port Kennedy Cave near the Schuylkill River in Pennsylvania. Cope found
10070-412: 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
10176-403: 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
10282-423: The teeth, and simulates the movements of jaws and neck of Smilodon fatalis (The "Robocat") on bison and elk carcasses, that the stabbing bite to the throat is a much more plausible and practical killing technique than the stabbing bite to the belly. The protruding incisors were arranged in an arch, and were used to hold the prey still and stabilize it while the canine bite was delivered. The contact surface between
10388-399: The upper canines of Smilodon would have been visible when the mouth was closed, while those of Homotherium would have not, after examining fossils and extant big cats. An apex predator , Smilodon primarily hunted large mammals. Isotopes preserved in the bones of S. fatalis in the La Brea Tar Pits reveal that ruminants like bison ( Bison antiquus , which was much larger than
10494-566: 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
10600-429: 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
10706-475: Was at least partially scansorial and therefore able to climb trees, Smilodon was probably completely terrestrial due to its greater weight and lack of climbing adaptations. Tracks from Argentina named Felipeda miramarensis in 2019 may have been produced by Smilodon . If correctly identified, the tracks indicate that the animal had fully retractible claws, plantigrade feet, lacked strong supination capabilities in its paws, notably robust forelimbs compared to
10812-683: Was found that S. fatalis had a slightly smaller repertoire than modern felids with 600 olfatory receptor genes, compared to 677 of a domestic cat . This indicates that S. fatalis used less olfaction for its daily activities than modern felids. Many Smilodon specimens have been excavated from asphalt seeps that acted as natural carnivore traps. Animals were accidentally trapped in the seeps and became bait for predators that came to scavenge, but these were then trapped themselves. The best-known of such traps are at La Brea in Los Angeles, which have produced over 166,000 Smilodon fatalis specimens that form
10918-517: Was less pronounced in S. fatalis than in the American lion. Christiansen and Harris found in 2012 that, as S. fatalis did exhibit some sexual dimorphism, there would have been evolutionary selection for competition between males. Some bones show evidence of having been bitten by other Smilodon , possibly the result of territorial battles, competition for breeding rights or over prey. Two S. populator skulls from Argentina show seemingly fatal, unhealed wounds which appear to have been caused by
11024-660: Was one of the last surviving machairodonts alongside Homotherium . Smilodon lived in the Americas during the Pleistocene epoch (2.5 mya – 10,000 years ago). The genus was named in 1842 based on fossils from Brazil; the generic name means "scalpel" or "two-edged knife" combined with "tooth". Three species are recognized today: S. gracilis , S. fatalis , and S. populator . The two latter species were probably descended from S. gracilis , which itself probably evolved from Megantereon . The hundreds of specimens obtained from
11130-538: Was the largest species, at 220 to 436 kg (485 to 961 lb) in weight and 120 cm (47 in) in height, and was among the largest known felids. The coat pattern of Smilodon is unknown, but it has been artistically restored with plain or spotted patterns. In North America, Smilodon hunted large herbivores such as bison and camels , and it remained successful even when encountering new prey taxa in South America such as Macrauchenia . Smilodon
11236-402: Was the smallest species at 55 to 100 kg (121 to 220 lb) in weight. S. fatalis had a weight of 160 to 280 kg (350 to 620 lb) and height of 100 cm (39 in). Both of these species are mainly known from North America , but remains from South America have also been attributed to them (primarily from the northwest of the continent). S. populator from South America
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