Machairodontini: Difference between revisions
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machairodontine tribes are all problematic, and likely should be redirected and discussed on the subfamily page Tag: New redirect |
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{{Taxobox |
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| name = '''Machairodontini''' |
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| fossil_range = {{Fossil range|middle Miocene|Pleistocene}} |
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| status = Fossil |
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| image = Homotheriumtex1.JPG |
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| image_caption = Skeleton of ''Homotherium serum'' from Texas Memorial Museum, University of Texas at Austin, Austin, Texas |
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| regnum = [[Animal]]ia |
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| phylum = [[Chordate|Chordata]] |
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| classis = [[Mammal]]ia |
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| ordo = [[Carnivora]] |
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| familia = [[Felidae]] |
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| subfamilia = †[[Machairodontinae]] |
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| tribus = †'''Machairodontini''' |
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| tribus_authority = [[Theodore Gill|Gill]], 1872 |
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| subdivision_ranks = [[Genus]] |
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| subdivision = |
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*†''[[Machairodus]]'' |
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*†''[[Miomachairodus]]'' |
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*†''[[Hemimachairodus]]'' |
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}} |
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'''Machairodontini''' is an extinct tribe of large [[saber-toothed cat]]s of the [[subfamily]] [[Machairodontinae]], that lived in [[Europe]], [[Asia]], [[Africa]], and [[North America]], during the late middle [[Miocene]] through late [[Pleistocene]] living from 11.6 [[Annum|mya]]–11 000 years ago.<ref>[http://paleodb.org/cgi-bin/bridge.pl?a=checkTaxonInfo&taxon_no=129891&is_real_user=1 Paleobiology Database: Machairodontini, Basic info].</ref> |
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Machairodont means “knife-tooth” which perfectly describes the species that make up Machairodontini. These predators are related to extant cats, the [[Felinae]], and share a common ancestor within the [[Felidae]] clade. Machairodontines are medium to large sized saber-toothed cats that would reach a size slightly larger than todays lions.<ref>Sotnikova, M. V. 1992. A new species of Machairodus from the late Miocene Kalmakpai locality in eastern Kazakhstan. Ann. Zool. Fennici. Vol. 28, p. 361-369</ref> This clade is also known as the [[Homotherini]], and includes species such as [[Machairodus]] and [[Homotherium]] (Figures 1, 2) as well as many others <ref>Christiansen, Per. 2013. Phylogeny of the saber-toothed felids (Carnivora: Felidae: Machairodontinae). Cladistics. Vol. 29, Issue 5, p. 543-559</ref>. They were first characterized by their [[scimitar]] canines in the upper jaw (Figure 3). This means that the canines are shorter and coarsely serrated, with vertical flattening <ref>Martin, L. D., Babiarz, J. P., Naples, V. L., & Hearst, J. 2000. Three ways to be a saber-toothed cat. Naturwissenschaften, Vol. 87, Issue 1, p. 41-44</ref><ref>Antón, Mauricio. 2013. Machairodont adaptations and affinities of the Holarctic late Miocene homotherin Machairodus(Mammalia, Carnivora, Felidae): the case of Machairodus catocopis Cope, 1887. Journal of Vertebrate Paleontology, Vol 33, Issue 5, p. 1202-1213.</ref>. Although the upper canines are shorter than other more famous saber toothed cats such [[Smilodon]], they are still abnormally long in comparison to the rest of the teeth in the mandible. There is also a space separating the canines and premolars known as a [[diastema]]. The bottom portion of the jaw contains small incisors that are in a straight row with a large, lower canine <ref>Sotnikova, M. V. 1992. A new species of Machairodus from the late Miocene Kalmakpai locality in eastern Kazakhstan. Ann. Zool. Fennici. Vol. 28, p. 361-369.</ref>. These canines are not nearly as big as the upper canines. There is a diastema between the [[canines]] of the and the [[premolars]] in the lower jaw as well. |
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These prehistoric predators not only have long upper canine teeth but they also have elongated limb bones <ref>Antón, Mauricio. 2013. Machairodont adaptations and affinities of the Holarctic late Miocene homotherin Machairodus(Mammalia, Carnivora, Felidae): the case of Machairodus catocopis Cope, 1887. Journal of Vertebrate Paleontology, Vol 33, Issue 5, p. 1202-1213.</ref>, which differ from the squatter legs of the other group of [[saber-toothed cats]], the [[Smilodontini]]. Although not many complete skeletons of machairodontine species have been found, those specimens known illustrate the long limb bones and shorter tails. The tails are of medium length and do not reach the ground as they do with cats today. |
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==Taxonomy== |
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Machairodontini was named by Gill (1872) as well as de Beaumont (1964). It was assigned to [[Machairodontinae]] by Berta and Galiano (1983).<ref>A. Berta and H. Galiano. 1983. Megantereon hesperus from the late Hemphillian of Florida with remarks on the phylogenetic relationships of machairodonts (Mammalia, Felidae, Machairodontinae). Journal of Paleontology 57(5):892-899</ref><ref>[http://taxonomicon.taxonomy.nl/TaxonTree.aspx?id=109077 Machairodontini], The Taxonomicon</ref> |
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==Geologic and Geographic Distribution== |
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The earliest machairodontine is the genus [[Miomachairodus]] from the late middle [[Miocene]] in [[Turkey]] <ref>Qiu, Zhanxiang. 2003. Dispersals of Neogene Carnivorans between Asia and North America. Bulletin of the American Museum of Natural History, N. 279, p. 18-31.</ref>. There are also species of the [[Machairodontini]] found in [[Africa]] from the late [[Miocene]] to the early [[Pleistocene]], in deposits such as Lothagam, Sahabi, and Langebaanweg <ref>Turner, A. 1998. Climate and evolution: implications of some extinction patterns in African and European Machairodontine Cats of the Plio-Pleistocene. Estudios Geológicos, Vol. 54, Issue 5-6, p. 209.</ref>. The [[Machairodontini]] moved East during the [[Vallesian]] (11.6-0.9 million years ago), when they entered [[Asia]] about 10 million years ago<ref>Qiu, Zhanxiang. 2003. Dispersals of Neogene Carnivorans between Asia and North America. Bulletin of the American Museum of Natural History, N. 279, p. 18-31.</ref> and became one of the major predators of this time<ref>Antón, M., Salesa, M. J., Morales, J., & Turner, A. 2004. First known complete skulls of the scimitar-toothed cat Machairodus aphanistus (Felidae, Carnivora) from the Spanish Late Miocene site of Batallones-1. Journal of Vertebrate Paleontology, Vol. 24, Issue 4, p. 957-969.</ref>. |
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There are also similarities between species found in [[North America]] and [[Eurasia]] that support an immigration event from [[Eurasia]] which took place before the late [[Miocene]], at about the end of the early [[Hemphillian]] (~5 million years ago)<ref>Qiu, Zhanxiang. 2003. Dispersals of Neogene Carnivorans between Asia and North America. Bulletin of the American Museum of Natural History, N. 279, p. 18-31.</ref><ref>Antón, Mauricio. 2013. Machairodont adaptations and affinities of the Holarctic late Miocene homotherin Machairodus(Mammalia, Carnivora, Felidae): the case of Machairodus catocopis Cope, 1887. Journal of Vertebrate Paleontology, Vol 33, Issue 5, p. 1202-1213.</ref>. The [[Old World]] (Europe/Africa/Asia) species [[Machairodus aphanistus]] and the [[New World]] (North and South America) species Machairodus catocopis are very closely related, suggesting that there was a migration and that these saber-toothed cats did radiate from Eurasia into North America<ref>Antón, Mauricio. 2013. Machairodont adaptations and affinities of the Holarctic late Miocene homotherin Machairodus(Mammalia, Carnivora, Felidae): the case of Machairodus catocopis Cope, 1887. Journal of Vertebrate Paleontology, Vol 33, Issue 5, p. 1202-1213.</ref>. This makes sense based on evolutionary similarities between North American and Eurasian species as well as the immigration of other species between these two continents at this time in Earth’s history <ref>Qiu, Zhanxiang. 2003. Dispersals of Neogene Carnivorans between Asia and North America. Bulletin of the American Museum of Natural History, N. 279, p. 18-31.</ref><ref>Antón, Mauricio. 2013. Machairodont adaptations and affinities of the Holarctic late Miocene homotherin Machairodus(Mammalia, Carnivora, Felidae): the case of Machairodus catocopis Cope, 1887. Journal of Vertebrate Paleontology, Vol 33, Issue 5, p. 1202-1213.</ref>. |
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There is also a species of [[Machairodontini]] that emmigrated to South America. [[Homotherium]] venezuelensis was found in El Breal de Orocual in [[Venezuela]]<ref>Rincon, A. D., Prevosti, F. J. & Parra, G. E. 2011. New saber-toothed cat records (Felidae: Machairodontinae) for the Pleistocene of Venezuela, and the Great American Biotic Interchange. Journal of Vertebrate Paleontology, Vol. 31, Issue 2, p. 468-478.</ref>. At this point in time, the continents had formed a land bridge between North and South America leading to much immigration from North to South and South to North. This event is known as the [[Great American Interchange]]. |
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==Evolutionary Relationships== |
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Previous analysis of the [[saber-toothed cats]] used [[Linnaean]] classification based the morphology of the upper canines, which suggested that there were four tribes within the subfamily of [[Machairodontinae]]. These tribes include Machairodontini, Homotherini, Smildontini, and Matailurini seen in the cladogram of [[Machairodontinae]]. Then upon finding further fossils, [[Machairodontini]] was assigned to the [[Homotherini]] tribe. The [[Homotherini]] includes species such as [[Machairodus]], M. aphanistus and M. giganteus. These species are characterized by their [[scimitar]] teeth that make up the large upper canines. The Smildontini tribe includes species such as Pramachairodus, [[Megantereon]], and [[Smilodon]]. These species have been characterized based on their longer, dagger-like teeth. The other tribe Matailurini includes species such as Matailurus and [[Dinofelis]]. These have been classified by having teeth different than the previous two clades, the long serrated teeth and the long, dagger-like teeth. Unfortunately, there are few postcranial skeletons of saber-toothed cats preserved, so available phylogenetic characters are largely cranial. |
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New research published in 2013 took a different approach to elucidating the evolutionary relationships of [[saber-toothed cats]]<ref>Christiansen, Per. 2013. [[Phylogeny]] of the saber-toothed felids (Carnivora: Felidae: Machairodontinae). Cladistics. Vol. 29, Issue 5, p. 543-559.</ref>. This approach used [[cladistic]] [[phylogeny]] instead of the previous [[Linnaean]] classification. The results concluded the original four tribes could not be recovered by parsimony analysis because many of the [[synapomorphies]] of the saber toothed cats are based on other bones that the prominent, upper canines. |
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Workers now regocnize a clade for true saber toothed cats called Eumachairodontia that includes species from all of the previously proposed tribes: Megantherron, [[Smilodon]], [[Amphimachairodus]], [[Homotherium]] and [[Xenosmilus]]. The [[synapomorphy]] for the “true saber-toothed” clade Eumachairodontia is the hypertrophied, greatly flattened upper canines. The true machairodontines have a synapomorphy of flattened, small, lower canines and other bone variations such as the small upper first molar compared to basal, pre saber toothed cats large, transversely situated upper first molar and large upper third premolar parastyle<ref>Christiansen, Per. 2013. Phylogeny of the saber-toothed felids (Carnivora: Felidae: Machairodontinae). Cladistics. Vol. 29, Issue 5, p. 543-559.</ref>. |
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==Morphology and Behavior== |
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The enlarged canines of these species were not only a unique morphological trait but also were used as a specialized hunting tool<ref>Meloro, Carlo. 2013. Cats in the forest: predicting habitat adaptations from humerus morphometry in extant and fossil Felidae (Carnivora). Paleobiology, Vol. 39, Issue 3, p. 323 -344.</ref>. It is proposed that the effective use of the specialized canines is the canine shear-bite. This is a model that shows how the teeth would bite a the surface of the prey’s neck, or other convex area of the body, and use the upper jaw as an anchor to pull the teeth down through the skin and create huge puncture wounds for blood loss and possibly tear a significant flesh wound<ref>Turner, A., Antón, M., Salesa, M. J., & Morales, J. 2011. Changing ideas about the evolution and functional morphology of Machairodontine felids. Estudios Geológicos, Vol. 67, Issue 2, p. 255-276.</ref><ref>Piras, P., Malorino, L., Teresi, L., Meloro, C., Lucci, F., Kotsakis, T., & Raia, P. 2013. Bite of the cats: relationships between functional integration and mechanical performance as revealed by mandible geometry. Systematic Biology, Vol. 62, Issue 6., p. 878-900.</ref>. The shearing bite as mentioned above would cause less tooth breakage when used in fast pursuit. |
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Some species within the Machairodontini show strong [[sexual dimorphism]], such as M. aphanistus, but others, such as Paramachairodus, display very slight [[sexual dimorphism]]. The canines of the males tend to be larger than the female canines. This could be due to mate competition for females<ref>Antón, M., Salesa, M. J., Morales, J., & Turner, A. 2004. First known complete skulls of the scimitar-toothed cat Machairodus aphanistus (Felidae, Carnivora) from the Spanish Late Miocene site of Batallones-1. Journal of Vertebrate Paleontology, Vol. 24, Issue 4, p. 957-969</ref>.. The varied dimorphism does suggest that different species had different forms of lifestyles as how today’s modern cats live<ref>Turner, A., Antón, M., Salesa, M. J., & Morales, J. 2011. Changing ideas about the evolution and functional morphology of Machairodontine felids. Estudios Geológicos, Vol. 67, Issue 2, p. 255-276.</ref>. |
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==References== |
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{{reflist}} |
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[[Category:Miocene carnivorans]] |
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[[Category:Pliocene carnivorans]] |
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[[Category:Pleistocene carnivorans]] |
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[[Category:Pleistocene extinctions]] |
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{{paleo-carnivora-stub}} |
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{{cat-stub}} |
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Latest revision as of 21:29, 19 December 2023
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