Editing Machairodus (section)

==History of research and taxonomy==
[[Image:Machairodus.png|thumb|upright|left|Early restoration by [[Lancelot Speed]] from 1905 depicting ''Machairodus'' with [[tiger]]-like markings. ]]
''Machairodus'' was first named in 1832, by German Naturalist [[Johann Jakob Kaup]]. Though its remains had been known since 1824, it was believed by [[Georges Cuvier]] that the fossils had come from a species of bear, which he called ''Ursus cultridens'' (known today as ''[[Megantereon]]'') based on composite sample of teeth from different countries, species and geologic ages, leading to what would become a long series of complications. Kaup however, recognized the teeth as those of felids and promptly reclassified the existing specimens as ''Machairodus'', including ''M. cultridens'' in it. The name quickly gained acceptance and by the end of the 19th century, many species of felid or related feliform (such as [[nimravids]]) were lumped into the genus ''Machairodus'', including but not limited to ''[[Sansanosmilus]]'', ''Megantereon'', ''[[Paramachairodus]]'', ''[[Amphimachairodus]]'', ''[[Nimravides]]'', and ''[[Homotherium]]'' among others. This would eventually turn ''Machairodus'' into something of a wastebasket taxon, which would be rectified with the discoveries of more complete skeletons of other machairodonts.{{sfnp|Antón|2013|pp=118–119}}

*''Machairodus irtyschensis'' and ''Machairodus ischimicus'' were described in 1936.<ref>{{Cite journal|author=J.A. Orlov |title=Tertiäre Raubtiere des westlichen Siberiens. I. Machairodontinae, Trav. Inst. Paléozool |journal=Acad. Sci. URSS |volume=5 |date=1936 |pages=111–152 |url=https://books.google.com/books?id=JEHWEAAAQBAJ&pg=PA111|language=German}}</ref>
*''Machairodus robinsoni'' was described in 1976.<ref>{{Cite journal|last=Kurtén |first=B. |date=1976 |title=Fossil Carnivora from the Late Tertiary of Bled Douarah and Cherichira, Tunisia |journal=Notes du Service Géologique de Tunisie |volume=42 |pages=177–214}}</ref> It was at one point referred to the genus ''[[Miomachairodus]]''.<ref>{{Cite journal|last=Beaumont |first=G. de |date=1978 |title=Notes complementaires sur quelques fe´lide´s (Carnivores) |journal=Archives des Sciences, Gene've |volume=31 |pages=219–27}}</ref>
*''Machairodus laskarevi'' was described in 1978.<ref>{{Cite journal|last1=Lungu |first1=A. N. |date=1978 |title=The Hipparion fauna of the middle Sarmatian of Moldavia (carnivorous mammals) |language=Russian |journal=Izd. Shtiintsa, Kishinev |pages=132}}</ref>
*''Machairodus alberdiae'' was first described in 1981,<ref>{{Cite journal|last1=Ginsburg |first1=L. |last2=Morales |first2=J. |last3=Soria |first3=D. |date=1981 |title=Nuevos datos sobre los carnívoros de los Valles de Fuentidueña (Segovia) |journal=Estud Geol |volume=37 |pages=383–415 |language=Spanish}}</ref> and extensively compared and retained as valid in 2017.<ref name="Fernandez-Monesillo2017" />
*''Machairodus kurteni'' was described in 1991.<ref>{{Cite journal|jstor=23735460 |title=A new species of Machairodus from the late Miocene Kalmakpai locality in eastern Kazakhstan (USSR) |last1=Sotnikova |first1=M. V. |journal=Annales Zoologici Fennici |date=1991 |volume=28 |issue=3/4 |pages=361–369 }}</ref> It was later referred to the genus ''Amphimachairodus''.
Some of the most important fossils of ''Machairodus'' have come from the [[Cerro de los Batallones]] fossil site in Spain, which are filled caverns which predominantly carnivores became trapped within after entering probably looking for food or water, with the remains of the species ''Machairodus aphanistus'' representing roughtly 1/4 of all bones found at the Batallones-1 cavern at the site.<ref>{{Cite journal |last1=Domingo |first1=M. Soledad |last2=Alberdi |first2=M. Teresa |last3=Azanza |first3=Beatriz |last4=Silva |first4=Pablo G. |last5=Morales |first5=Jorge |date=2013-05-01 |editor-last=Farke |editor-first=Andrew A. |title=Origin of an Assemblage Massively Dominated by Carnivorans from the Miocene of Spain |journal=PLOS ONE |language=en |volume=8 |issue=5 |pages=e63046 |doi=10.1371/journal.pone.0063046 |doi-access=free |issn=1932-6203 |pmc=3641116 |pmid=23650542|bibcode=2013PLoSO...863046D }}</ref>

The fossil species assigned to the genus ''Machairodus'' were divided by Turner into two grades of evolutionary development, with ''M. aphanistus'' and the North American "''Nimravides''" ''catacopis'' representing the more primitive grade and ''M. coloradensis'' and ''M. giganteus'' representing the more derived grade.<ref name="Turner">{{Cite book |last=Turner |first=Alan |url=https://books.google.com/books?id=66mRJSxIAfoC |title=The Big Cats and Their Fossil Relatives |date=1997 |publisher=[[Columbia University Press]] |others=Illustrated by Mauricio Antón |isbn=978-0-231-10228-5 |pages=233}}</ref> The characteristics of the more advanced grade include a relative elongation of the forearm and a shortening of the lumbar region of the spine to resemble that in living pantherine cats.<ref name="Turner" /> Subsequently, the more derived forms were assigned a new genus, ''Amphimachairodus'', which includes ''M. coloradensis'', ''M. kurteni'', ''M. kabir'' and ''M. giganteus''{{sfnp|Antón|2013}} and recently ''M. horribilis''.<ref name="RuizRamoni2019">{{Cite journal |last1=Ruiz-Ramoni |first1=Damián |last2=Rincón |first2=Ascanio D. |last3=Montellano-Ballesteros |first3=Marisol |date=2020 |title=Taxonomic revision of a Machairodontinae (Felidae) from the Late Hemphillian of México |journal=Historical Biology |volume=32 |issue=10 |pages=1312–1319 |doi=10.1080/08912963.2019.1583750 |s2cid=91277834}}</ref> In addition, ''M. catacopsis'' and ''M. lahayishupup'' was reclassified as ''N. catacopsis''.<ref name="Jiangzuo2022">{{Cite journal |last1=Jiangzuo |first1=Qigao |last2=Li |first2=Shijie |last3=Deng |first3=Tao |date=2022 |title=Parallelism and lineage replacement of the late Miocene scimitar-toothed cats from the old and New World |url=https://www.cell.com/iscience/pdf/S2589-0042(22)01909-5.pdf |journal=iScience |volume=25 |issue=12 |page=105637 |bibcode=2022iSci...25j5637J |doi=10.1016/j.isci.2022.105637 |pmc=9730133 |pmid=36505925}}</ref>

Modern scholarship generally classifies ''Machairodus'' as one of the most basal members of the tribe [[Homotherini]] (with some authors retaining the name "Machairodontini" for the group<ref>{{Cite journal |last1=Jiangzuo |first1=Qigao |last2=Werdelin |first2=Lars |last3=Sanisidro |first3=Oscar |last4=Yang |first4=Rong |last5=Fu |first5=Jiao |last6=Li |first6=Shijie |last7=Wang |first7=Shiqi |last8=Deng |first8=Tao |date=2023-04-26 |title=Origin of adaptations to open environments and social behaviour in sabretoothed cats from the northeastern border of the Tibetan Plateau |journal=Proceedings of the Royal Society B: Biological Sciences |language=en |volume=290 |issue=1997 |doi=10.1098/rspb.2023.0019 |issn=0962-8452 |pmc=10113030 |pmid=37072045}}</ref>).<ref name="AntónSalesa2013">{{cite journal |last1=Antón |first1=Mauricio |last2=Salesa |first2=Manuel J. |last3=Siliceo |first3=Gema |year=2013 |title=Machairodont adaptations and affinities of the Holarctic late Miocene homotherin Machairodus(Mammalia, Carnivora, Felidae): the case of Machairodus catocopis Cope, 1887 |journal=Journal of Vertebrate Paleontology |volume=33 |issue=5 |pages=1202–1213 |bibcode=2013JVPal..33.1202A |doi=10.1080/02724634.2013.760468 |issn=0272-4634 |s2cid=86067845 |hdl=10261/93630}}</ref> ''Machairodus'' is thought to be a [[Paraphyly|paraphyletic]] [[evolutionary grade]] that is ancestral to ''Amphimachairodus'' (which is in turn ancestral to other homotheriines like ''Homotherium'').<ref name="jiangzuo etal 2022">{{Cite journal |last1=Jiangzuo |first1=Qigao |last2=Werdelin |first2=Lars |last3=Sun |first3=Yuanlin |date=May 2022 |title=A dwarf sabertooth cat (''Felidae'': ''Machairodontinae'') from Shanxi, China, and the phylogeny of the sabertooth tribe ''Machairodontini'' |journal=Quaternary Science Reviews |language=en |volume=284 |at=Article 107517 |bibcode=2022QSRv..28407517J |doi=10.1016/j.quascirev.2022.107517}}</ref>

''M. robinsoni'' is the earliest species within the genus, evolving during the late [[Middle Miocene]], around 12.5 [[Year|Ma]] in [[Tunisia]], and is the only currently recognized species within the genus that inhabited Africa. The oldest occurrence of ''M. aphanistus'' within Vallès-Penedès Basin was 10.4 Ma. With the youngest occurrence within MN10 localities, 9.1 Ma. The chronostratigraphic range of ''M. aphanistus'' within the basin correlates with its chronological distribution across Europe. The genus was later succeeded by ''A. giganteus'' during the early Turolian in Europe.<ref>{{cite journal |last1=Malapeira |first1=J.M |last2=Robles |first2=J. M. |last3=Vilar |first3=I. C. |last4=Abella |first4=Juan |last5=Obradó |first5=Pau |last6=Alba |first6=D. M. |date=October 7, 2014 |title=The scimitar-toothed cat Machairodus aphanistus (Carnivora: Felidae) in the Vallès-Penedès Basin (NE Iberian Peninsula)Le chat à dents sabre Machairodus aphanistus (Carnivora : Felidae) dans le bassin de Vallès-Penedès (Nord-Est de la péninsule Ibérique) |journal=Comptes Rendus Palevol |volume=13 |issue=7 |doi=10.1016/j.crpv.2014.05.001 |doi-access=free}}</ref>