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{{Short description|Extinct genus of mammals}}
{{Automatic taxobox
{{Automatic taxobox
| fossil_range = {{Fossil range|Middle Eocene|Early Oligocene}}
| fossil_range = {{Fossil range|Middle Eocene|Early Oligocene}}
| image = Plagiolophus 1.JPG
| image = Museum of Natural History Palaeotherium magnum.jpg
| image_caption = ''P. magnum'' skeleton
| image_caption = ''Plagiolophus'' skeleton
| taxon = Palaeotherium
| taxon = Plagiolophus
| authority = [[George Cuvier|Cuvier]], 1804
| authority = [[Auguste Pomel|Pomel]], 1847
| type_species = {{extinct}}'''''Palaeotherium magnum'''''
| type_species = {{extinct}}''[[Palaeotherium]] minus'' <br>(= †'''''Plagiolophus minor''''')
| type_species_authority = Cuvier, 1804
| type_species_authority = [[Georges Cuvier|Cuvier]], 1804
| subdivision_ranks = Other species
| subdivision_ranks = Other species
| subdivision = {{species list
| subdivision = {{species list
|{{extinct}}'''''P.&nbsp;medium'''''|Cuvier, 1804
|{{extinct}}'''''P.&nbsp;ovinus'''''|[[Auguste Aymard|Aymard]], 1846
|{{extinct}}'''''P.&nbsp;crassum'''''|Cuvier, 1805
|{{extinct}}'''''P.&nbsp;annectens'''''|[[Richard Owen|Owen]], 1848
|{{extinct}}'''''P.&nbsp;curtum'''''|Cuvier, 1812
|{{extinct}}'''''P.&nbsp;fraasi'''''|[[Christian Erich Hermann von Meyer|von Meyer]], 1852
|{{extinct}}'''''P.&nbsp;duvali'''''|[[Auguste Pomel|Pomel]], 1853
|{{extinct}}'''''P.&nbsp;javali'''''|[[Henri Filhol|Filhol]], 1877
|{{extinct}}'''''P.&nbsp;castrense'''''|[[Jean-Baptiste Noulet|Noulet]], 1863
|{{extinct}}'''''P.&nbsp;lugdunensis'''''|[[Charles Depéret|Depéret]] & Carrière, 1901
|{{extinct}}'''''P.&nbsp;siderolithicum'''''|[[François Jules Pictet de la Rive|Pictet]] & [[Aloïs Humbert|Humbert]], 1869
|{{extinct}}'''''P.&nbsp;cartailhaci'''''|[[Hans Georg Stehlin|Stehlin]], 1904
|{{extinct}}'''''P.&nbsp;eocaenum'''''|[[Paul Gervais|Gervais]], 1875
|{{extinct}}'''''P.&nbsp;cartieri'''''|Stehlin, 1904
|{{extinct}}'''''P.&nbsp;lautricense'''''|[[Hans Georg Stehlin|Stehlin]], 1904
|{{extinct}}'''''P.&nbsp;oweni'''''|Depéret, 1917
|{{extinct}}'''''P.&nbsp;muehlbergi'''''|Stehlin, 1904
|{{extinct}}'''''P.&nbsp;curtisi'''''|Hooker, 1986
|{{extinct}}'''''P.&nbsp;renevieri'''''|Stehlin, 1904
|{{extinct}}'''''P.&nbsp;major'''''|Brunet & Jehenne, 1989
|{{extinct}}'''''P.&nbsp;ruetimeyeri'''''|Stehlin, 1904
|{{extinct}}'''''P.&nbsp;ministri'''''|Brunet & Jehenne, 1989
|{{extinct}}'''''P.&nbsp;pomeli'''''|[[Jens Lorenz Franzen|Franzen]], 1968
|{{extinct}}'''''P.&nbsp;casasecaensis'''''|Cuesta, 1994
|{{extinct}}'''''P.&nbsp;crusafonti'''''|Casanovas-Cladellas, 1975
|{{extinct}}'''''P.&nbsp;mazateronensis'''''|Cuesta, 1994
|{{extinct}}'''''P.&nbsp;llamaquiquense'''''|Casanovas-Cladellas & Santafé-Llopis, 1991
|{{extinct}}'''''P.&nbsp;huerzeleri'''''|Remy, 2000
|{{extinct}}'''''P.&nbsp;giganteum'''''|Cuesta, 1993
|{{extinct}}'''''P.&nbsp;ringeadei'''''|Remy, 2004
|{{extinct}}'''''P.&nbsp;mamertensis'''''|Remy, 2004
}}
''For subspecies suggested, see [[#List of lineages|below]].''
| synonyms = {{collapsible list|bullets = true|title=<small>Genus synonymy</small>
| ''Paleotherium'' {{small|Cuvier, 1804}}
| ''Paloeotherium'' {{small|Cuvier, 1804}}
| ''Palaetherium'' {{small|[[Constantine Samuel Rafinesque|Rafinesque]], 1814}}
| ''Paloetherium'' {{small|Rafinesque, 1814}}
| ''Salaeotherium'' {{small|[[François Désiré Roulin|Roulin]], 1829}}
| ''Palacotherium'' {{small|[[Christian Erich Hermann von Meyer|von Meyer]], 1838}}
}}
{{collapsible list|bullets = true
|title=<small>Synonyms of ''P.&nbsp;magnum''</small>
|''P. girondicum'' {{small|[[Henri Marie Ducrotay de Blainville|Blainville]], 1846}}
|''P. aniciense'' {{small|[[Paul Gervais|Gervais]], 1848–1852}}
|''P. subgracile'' {{small|[[Auguste Aymard|Aymard]], 1853}}
|''P. magnum parisiense'' {{small|Gervais, 1859}}
|''P. stehlini'' {{small|[[Charles Depéret|Depéret]], 1917}}
|''P. franzeni'' {{small|Casanovas-Cladellas & Santafé-Llopis, 1980}}
}}
{{collapsible list|bullets = true
|title=<small>Synonyms of ''P.&nbsp;medium''</small>
|''P. brivatense'' {{small|[[Auguste Bravard|Bravard]], 1843}}
|''P. suevicum'' {{small|Fraas, 1869}}
|''P. möschi'' {{small|Stehlin, 1904}}
|''P. euzetense'' {{small|Depéret, 1917}}
}}
{{collapsible list|bullets = true
|title=<small>Synonyms of ''P.&nbsp;crassum''</small>
|''P. indeterminatum'' {{small|Cuvier, 1822}}
}}
{{collapsible list|bullets = true
|title=<small>Synonyms of ''P.&nbsp;curtum''</small>
|''P. latum'' {{small|Cuvier, 1822}}
|''P. buseri'' {{small|Stehlin, 1904}}
}}
{{collapsible list|bullets = true
|title=<small>Synonyms of ''P.&nbsp;duvali''</small>
|''P. heimi'' {{small|Stehlin, 1904}}
|''P. kleini'' {{small|[[Wilhelm Otto Dietrich|Dietrich]], 1922}}
}}
{{collapsible list|bullets = true
|title=<small>Synonyms of ''P.&nbsp;muehlbergi''</small>
|''P. velaunum'' {{small|Blainville, 1848}}
}}
{{collapsible list|bullets = true
|title=<small>Dubious species</small>
|''P. gracile'' {{small|von Meyer, 1839}}
|''P. parvulum'' {{small|[[Pierre Toussaint Marcel de Serres de Mesplès|de Serres]], 1844}}
|''P. commune'' {{small|Blainville, 1846}}
|''P. primaevum'' {{small|Aymard, 1853}}
|''P. gervaisii'' {{small|Aymard, 1853}}
}}
}}
}}
}}


'''''Palaeotherium''''' ([[Ancient greek language|Ancient Greek]] for 'old beast') is an extinct genus of [[perissodactyl]] [[ungulate]] known from the Mid [[Eocene]] to earliest [[Oligocene]] of [[Europe]]. First described by French naturalist [[Georges Cuvier]] in 1804, ''Palaeotherium'' was among the first [[Paleogene]] [[Mammal|mammals]] to be described.




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== Research history ==
=== First descriptions ===
[[File:Palaeotherium medium skull Lamanon 1782.jpg|thumb|left|Fossil skull of ''Palaeotherium medium'' as illustrated in 1782]]
In 1782, the French naturalist [[Robert de Lamanon]] described a fossil skull retaining the upper and lower jaws that was collected from the quarries of [[Montmartre]], a large hill near [[Paris]], France, that belonged to the nobleman [[Philippe-Laurent de Joubert]]. He recognized that the morphologies of its [[molar (tooth)|molars]] and [[incisor]]s were roughly akin to those of [[ruminant]]s but noted that its dentition still lacked any modern analogues. As a result, he hypothesized that the animal was extinct, had amphibious behaviors, and fed on both herbs and fish.<ref>{{cite journal|last=de Lamanon|first=Robert de Paul|year=1782|title=Description de divers fossiles trouvés dans les carrières de Montmartre près Paris, & vues générales sur la formation des pierres gypseuses|journal=Introduction aux Observations sur la Physique, sur l'Histoire Naturelle et sur les Arts|volume=19|pages=173–194|url=https://books.google.fr/books?id=UBcAAAAAMAAJ&hl=fr&pg=PA173}}</ref><ref name="culturalism">{{cite book|editor-last1=Chemla|editor-first1=Karine|editor-last2=Keller|editor-first2=Evelyn Fox|last=Belhoste|first=Bruno|year=2017|title=Cultures without Culturalism: The Making of Scientific Knowledge|chapter=Chapter 10: From Quarry to Paper. Cuvier’s Three Epistemological Cultures|publisher=Duke University Press|pages=250–277}}</ref>


Since 1796, the French naturalist [[Georges Cuvier]] innovated the idea of vanished worlds of extinct animals, but as his observations of fossils were mostly limited to drawings and very fragmentary fossil materials stored at the [[National Museum of Natural History, France]], his palaeontological insight remained limited early on. The fossils of Montmartre were credited with great importance to the field of palaeontology, as the fossil taxa found near Paris were embedded in deeper and harder sediments, falling between the [[Pleistocene]]-aged mammals and the [[Cretaceous]]-aged reptiles.<ref name="culturalism"/> In 1798, he documented fossils from Montmartre, suggesting initially that they could have belonged to the [[canid]] genus ''[[Canis]]'' based on its dentition.<ref>{{cite journal|last=Cuvier|first=Georges|year=1798|title=Extrait d’un Mémoire sur les ossemens fossiles de quadrupèdes|journal=Bulletin des sciences par la Société Philomathique|volume=18|pages=137–139|url=https://www.biodiversitylibrary.org/item/97128#page/322/mode/1up}}</ref> Not long after in the same year, he changed his mind and thought that the fossil mammal instead would have been within the order of [[Pachydermata|pachyderms]], theorizing that it would have been closest to [[tapir]]s and that it would have had trunks like them. He also figured out that the animals of Montmartre comprised of multiple different species with different sizes and numbers of toes.<ref>{{cite journal|last=Cuvier|first=Georges|year=1798|title=Sur les ossemens qui se trouvent dans le gypse de Montmartre|journal=Bulletin des sciences par la Société Philomathique|volume=20|pages=154–155|url=https://www.biodiversitylibrary.org/item/97128#page/343/mode/1up}}</ref><ref name="culturalism"/>


=== Early taxonomy and depictions ===
{{multiple image
| align = left
| image1=Palaeotherium medium skull sketch 1804.jpg
| image2=Palaeotherium medium fossils sketch skull reconstruction 1804.jpg
| footer = Sketches of the skull fossil of ''P. medium'' (left) and reconstructed ''P. medium'' skull drawings among other fossil assortments (right)
}}
In 1804, Georges Cuvier described the sets of fossils from the gypsum quarries of the outskirts of Paris (known as the [[Paris Basin]]). Describing the skull previously reported by de Lamanon, he confirmed that it belonged to a mammal, had a complete set of 44 total teeth, and had molar morphologies similar to those of [[rhinoceros]]es and [[hyrax]]es. The naturalist, recognizing that its separate affinities from other mammals, established the genus name ''Palaeotherium'' and established the first species name ''Palaeotherium medium''.<ref name="origin">{{cite journal|last=Cuvier|first=Georges|year=1804|title=Sur les espèces d'animaux dont proviennent les os fossiles répandus dans la pierre à plâtre des environs de Paris|journal=Annales du Muséum National d'Histoire Naturelle, Paris|language=french|volume=3|pages=275–303|url=https://www.biodiversitylibrary.org/item/51193#page/343/mode/1up}}</ref><ref>{{cite journal|last=Rudwick|first=Martin J. S.|year=2022|title=Georges Cuvier's appeal for international collaboration, 1800|journal=History of Geology|volume=46|number=1|pages=117–125 |doi=10.18814/epiiugs/2022/022002|s2cid=246893918 |doi-access=free}}</ref> The genus name means "ancient beast," for which the etymology is a compound of the [[Greek language|Greek]] prefix {{lang|grc|παλαιός}} ({{transliteration|grc|'palaios'}}) meaning 'old' or 'ancient' and the suffix {{lang|grc|θήρ}} ({{transliteration|grc|'thēr'}}) meaning 'beast' or 'wild animal'.<ref>{{cite book |last1=Roberts |first1=George |title=An etymological and explanatory dictionary of the terms and language of geology |year=1839 |publisher=Longman, Orme, Brown, Green, & Longmans |location=London |page=8 |url=https://archive.org/details/anetymologicala00robegoog |access-date=29 December 2021 |language=English}}</ref> He debunked Lamanon's hypothesis that ''Palaeotherium'' was an omnivorous amphibian and suspected that it had trunks akin to those of tapirs.<ref name="origin"/><ref name="culturalism"/>


Later, he wrote about a species that he deemed to have similar dentition to ''P. medium'' to the extent that it belonged to ''Palaeotherium''. Cuvier observed that the species had larger-sized dentition compared to the other species based on imprints that he was provided. Thus, he established the species ''Palaeotherium magnum''. He also erected the genus ''[[Anoplotherium]]'' in recognition of its differing dentition from that of ''Palaeotherium''.<ref>{{cite journal|last=Cuvier|first=Georges|year=1804|title=Suite des Recherches: Sur les espèces d'animaux dont proviennent les os fossiles répandus dans la pierre à plâtre des environs de Paris.|journal=Annales du Muséum National d'Histoire Naturelle, Paris|language=french|volume=3|pages=364–387|url=https://www.biodiversitylibrary.org/item/51193#page/1/mode/1up|access-date=2023-08-30|archive-date=2023-07-27|archive-url=https://web.archive.org/web/20230727022652/https://www.biodiversitylibrary.org/item/51193#page/1/mode/1up|url-status=live}}</ref> He also gave mentions to the postcranial fossils of the genus and listed a newly recognized species named ''Palaeotherium minus''.<ref>{{cite journal|last=Cuvier|first=Georges|year=1804|title=Suite des Recherches: Suite de recherches sur les os fossiles de la pierre à plâtre des environs de Paris. Troisième mémoire. Restitution des pieds. Première section. Restitution des différens pieds de derrière.|journal=Annales du Muséum National d'Histoire Naturelle, Paris|language=french|volume=3|pages=442–472|url=https://www.biodiversitylibrary.org/item/51193#page/1/mode/1up|archive-date=2023-07-27|archive-url=https://web.archive.org/web/20230727022652/https://www.biodiversitylibrary.org/item/51193#page/1/mode/1up|url-status=live}}</ref> In a later journal of the same year, Cuvier described a mostly complete skeleton from the [[communes of France|French commune]] of [[Pantin]] that he determined to have belonged to ''P. minus''.<ref>{{cite journal|last=Cuvier|first=Georges|year=1804|title=Suite de recherches sur les os fossiles de la pierre à plâtre des environs de Paris. Cinquiéme Mémoire. Sur les os du Tronc. Premiére Section. Description d'un squelette presque entier trouvé dans les carriéres de Pantin|journal=Annales du Muséum National d'Histoire Naturelle, Paris|language=french|volume=4|pages=66–81|url=https://www.biodiversitylibrary.org/item/51194#page/76/mode/1up}}</ref>


[[File:Palaeotherium magnum skeleton reconstruction 1822.jpg|thumb|left|Reconstruction of the skeleton of ''P. magnum'' as depicted in 1822]]
In 1805, Cuvier described additional postcranial fossil bones of ''Palaeotherium''. He noted that its forefeet consisted of three short toes and that no other animal had postcranial bones that closely resembled those of the extinct genus. Nonetheless, he also gave emphasis to some of the fossil foot bones resembling those of either tapirs or rhinoceroses. Based on the [[metacarpal]] bone shapes located on the front feet, he erected the species name ''P. crassum'', mentioning that it was a distinct species from ''P. medium''.<ref>{{cite journal|last=Cuvier|first=Georges|year=1805|title=Troisième mémoire. Deuxième section. Restitution des différens pieds de devant|journal=Annales du Muséum d'Histoire Naturelle|language=french|volume=6|pages=253–283|url=https://www.biodiversitylibrary.org/item/188443#page/7/mode/1up}}</ref>


In 1812, he examined more metacarpal bone material that he classified as belonging to ''Palaeotherium''. He stated that the newer material was nearly the size of those of ''P. crassum'' but that it was shorter than even those of ''P. minus''. Thus, he felt the need to establish another species ''P. curtum'' based on the fossils. He then made a review of the species he previously erected. According to Cuvier, ''P. magnum'' was the size of a horse. He then stated that both ''P. medium'' and ''P. crassum'' were both the size of a pig, the former having narrow and elongated feet and the having broader and shorter feet. ''P. curtum'' did not have any listed size analogue, but the naturalist said that it had the feet of a horse. Finally, he said that ''P. minus'' was the size of a sheep and had narrow feet. He also listed five new additional species from surrounding areas of France that he did not further elaborate on, such as the rhinoceros-sized ''P. giganteum'', the ox-sized ''P. tapiroïdes'', the pig-sized ''P. buxovillanum'' plus ''P. aurelianense'', and the sheep-sized ''P. occitanicum''.<ref name="research">{{cite book|last=Cuvier|first=Geoges|year=1812|title=Recherches sur les ossemens fossiles de quadrupèdes: où l'on rétablit les caractères de plusieurs espèces d'animaux que les révolutions du globe paroissent avoir détruites|chapter=Résumé général et rétablissement des Squelettes des diverses espèces|volume=3|language=french|publisher=Chez Deterville|url=https://www.biodiversitylibrary.org/item/123872#page/1/mode/1up|archive-date=2023-07-31|archive-url=https://web.archive.org/web/20230731200748/https://www.biodiversitylibrary.org/item/123872#page/1/mode/1up|url-status=live}}</ref>


[[File:Charles Laurillardi Palaeotherium Anoplotherium Drawings 1822.png|thumb|Drawings of species classified to ''Palaeotherium'' and ''[[Anoplotherium]]'' by [[Charles Léopold Laurillard]] under the work of [[Georges Cuvier]]]]
The naturalist also suggested palaeobiologies of the four species of ''Palaeotherium'' that he described from the gypsum quarries. He acknowledged that ''P. magnum'' had skull and limb bone material but lacked [[vertebra]] and [[rib]] fossils. Regardless, he was able to speculate based on available material that ''P. magnum'' would have resembled a tapir the size of a horse with bare amounts of hair. He also hypothesized that ''P. crassum'' would have resembled a tapir and been the size of one, which in theory would have caused people to confuse the two. ''P. medium'', he suggested, would have also resembled a tapir but differed by higher legs and longer feet. He was able to construct a speculative skeletal reconstruction drawing of ''P. minus'' because of a previously found skeleton and hypothesized that it was smaller than a sheep and could have been cursorial with its slender legs and face. Finally, he theorized that ''P. curtum'' would have been the bulkiest species with lower legs compared to ''P. minus'' that were stocky like those of ''P. crassum''. Cuvier also suggested that ''Palaeotherium'' as in the entire genus was tridactyl (or three-toed).<ref name="research"/><ref>{{cite book|last=Rudwick|first=Martin J. S.|year=1997|title=Georges Cuvier, Fossil Bones, and Geological Catastrophes: New Translations and Interpretations of the Primary Texts|chapter=Chapter 6: The Animals from the Gypsum Beds around Paris|publisher=University of Chicago Press}}</ref>


In 1822, Cuvier recognized additional species of ''Palaeotherium'' based on postcranial materials. He also depicted a drawn reconstruction of the skeleton of ''P. magnum'', outlining that it was the size of a [[Javan rhinoceros]], was stocky in body build, and had a massive head.<ref name="subgenus">{{cite book|last=Cuvier|first=Georges|year=1822|title=Recherches sur les ossemens fossiles, où l'on rétablit les caractères de plusieurs animaux dont les révolutions du globe ont détruit les espèces|publisher=G. Dufour and E. d'Ocagne|volume=3|url=https://www.biodiversitylibrary.org/item/214528#page/1/mode/1up|access-date=2023-08-30|archive-date=2023-08-19|archive-url=https://web.archive.org/web/20230819062404/https://www.biodiversitylibrary.org/item/214528#page/1/mode/1up|url-status=live}}</ref> ''Palaeotherium'' was also depicted in 1822 drawings by the French palaeontologist [[Charles Léopold Laurillard]] under the direction of Cuvier.<ref>{{cite book|last=Rudwick|first=Martin J.S.|year=1992|title=Scenes from Deep Time: Early Pictorial Representations of the Prehistoric World|chapter=Chapter 2: Keyholes into the Past|pages=27–58}}</ref> In 1824, he listed most species of ''Palaeotherium'' that he previously named and described, namely ''P. magnum'', ''P. medium'', ''P. crassum'', ''P. latum'', ''P. curtum'', ''P. minus'', and ''P. aureliense''. He also recognized an additional species ''P. isselanum'', but he did not describe its fossils.<ref>{{cite book|last=Cuvier|first=Georges|year=1824|title=Recherches sur les ossemens fossiles, où l'on rétablit les caractères de plusieurs animaux dont les révolutions du globe ont détruit les espèces|publisher=G. Dufour and E. d'Ocagne|volume=5|issue=2|url=https://www.biodiversitylibrary.org/item/214698#page/536/mode/1up}}</ref>


[[File:Palaeotherium Crystal Palace 2018.jpg|thumb|left|Sculpture of ''P. medium'' as part of the [[Crystal Palace Dinosaurs]] sculptures on the Tertiary Island of the [[Crystal Palace Park]], United Kingdom]]
''Palaeotherium magnum'', ''Palaeotherium medium'' and "''Plagiolophus minus''" (= ''[[Plagiolophus (mammal)|Plagiolophus]]'') are notably depicted in the forms of one sculpture representing each species in the [[Crystal Palace Dinosaurs]] attraction in the [[Crystal Palace Park]] in the United Kingdom, open to the public since 1854 and constructed by English sculptor [[Benjamin Waterhouse Hawkins]]. The original large-sized ''P. magnum'' sculpture was lost at some point after 1958 and was replaced by a new replicated model in 2023. The other two palaeothere statues in the park represent the medium-sized ''P. medium'' and the small-sized "''P. minus''" (= ''[[Plagiolophus (mammal)|Plagiolophus]] minor''). Both the large ''P. magnum'' and ''P. medium'' were posed in standing positions whereas the smallest sitting statue was made to represent "''P. minus''". The models' resemblances to tapirs reflected early perceptions that the palaeothere species resembled them in body plan appearances. Despite this, the sculptures differ from living tapirs in several ways, such as shorter plus taller faces, higher eye positions, slender legs, longer tails, and the presence of three toes on the forelimbs unlike the four toes of the forelimbs of tapirs.<ref>{{cite web|last=Ashworth|first=James|date=1 July 2023|title=Missing Crystal Palace mammal recreated decades after disappearance|website=Natural History Museum in London|url=https://www.nhm.ac.uk/discover/news/2023/july/missing-crystal-palace-mammal-recreated-decades-after-disappearance.html|archive-url=https://web.archive.org/web/20230701110222/https://www.nhm.ac.uk/discover/news/2023/july/missing-crystal-palace-mammal-recreated-decades-after-disappearance.html|archive-date=1 July 2023|access-date=1 June 2024}}</ref><ref name="crystal">{{cite book|last1=Witton|first1=Mark P.|last2=Michel|first2=Ellinor|year=2022|title=The Art and Science of the Crystal Palace Dinosaurs|chapter=Chapter 4: The sculptures: mammals|publisher=The Crowood Press|pages=68–91}}</ref>


Of the three sculptures, ''P. medium'' most closely resembles a tapir, and it has remained mostly intact but suffered from damages that were eventually repaired. ''P. medium'' was depicted as having durable skin and a slender face with a trunk, representing archaic perceptions that it was a slow animal that lived in closed habitats. The original ''P. magnum'' sculpture was last known from a 1958 photograph of it that reveals that it was the largest sculpture of the three species and that it had a highly robust form with large and deep eyes, a proportionally large head, bulky legs, and a muscular-looking body plan. The trunk of the model appears to start from the upper section of the skull and descends down to the lower lip. The overall anatomy of the sculpture appears to have been based off of elephants compared to the other two palaeothere statues.<ref name="crystal"/>


=== Later 19th century taxonomy ===
{{multiple image
| align = left
| image1= Palaeotherium species skulls osteography.jpg
| image2= Palaeotherium foot bones.jpg
| total_width = 400
| total_height= 400
| footer = Illustrations of the fossil skulls (left) and limbs (right) of multiple palaeothere species including those of ''Palaeotherium''
}}
Throughout much of the 19th century, many species were classified under ''Palaeotherium'', some of which were eventually reclassified under different genera.<ref name="revisions">{{cite thesis|type=Inaugural Dissertation|last=Franzen|first=Jens L.|year=1968|title=Revision der Gattung Palaeotherium Cuvier, 1804 (Palaeotheriidae, Perissodactyla, Mammalia). Band 1|publisher=University of Freiburg}}</ref> For instance, "''P.''" ''aurelianense'' was reclassified to its own genus ''[[Anchitherium]]'' by [[Christian Erich Hermann von Meyer]] in 1844. In an 1839–1864 osteography, the French naturalist [[Henri Marie Ducrotay de Blainville]] relisted "''P.''" ''tapiroides'', "''P.''" ''buxovillanum'' and "''P.''" ''occitanicum'' as species belonging to ''[[Lophiodon]]'',<ref name="osteography">{{cite book|last=de Blainville|first=Henri Marie Ducrotay|year=1839–1864|title=Ostéographie, ou, Description iconographique comparée du squelette et du système dentaire des Mammifères récents et fossiles : pour servir de base à la zoologie et à la géologie|publisher=Arthus Bertrand|volume=4|url=https://www.biodiversitylibrary.org/item/265877#page/9/mode/1up}}</ref> but the latter two were eventually reclassified to ''[[Paralophiodon]]'' and ''[[Lophiaspis]]'', respectively in the 20th century.<ref>{{cite journal|last=Depéret|first=Charles|year=1910|title=Études sur la famille des Lophiodontidés|journal=Bulletin de la Société géologique de France|pages=558–577}}</ref><ref>{{cite journal|last=Dedieu|first=Pierre|year=1977|title=Sur la Systématique des Tapiroidea (Mammalia) de l’Éocène européen|journal=Comptes Rendus des séances de l’Académie des Sciences de Paris, Sciences de la vie D|volume=284|pages=2219–2222}}</ref> In 1862, Swiss zoologist [[Ludwig Ruetimeyer]] defined the previously recognized genera ''Plagiolophus'' and ''[[Propalaeotherium]]'' as distinct from ''Palaeotherium'' and containing the species ''P. minor'' and ''P. isselanum'', respectively.<ref>{{cite journal|last=Ruetimeyer|first=Ludwig|year=1862|title=Eocaene Säugethiere Gebiet des Schweizerischen Jura|journal=Neue Denkschriften der Allg. Schweizerischen Gesellschaft für die Gesammten Naturwissenschaften|volume=19|pages=1–98|url=https://www.biodiversitylibrary.org/item/47574#page/485/mode/1up}}</ref>


In 1853, Pomel erected the species ''P. duvali'' based on fossil limbs that he thought to have been less stocky compared to those of ''P. curtum''.<ref name="duvali">{{cite book|last=Pomel|first=Auguste|year=1853|title=Catalogue méthodique et descriptif des vertébrés fossiles découverts dans le bassin hydrographique supérieur de la Loire, et surtout dans la vallée de son affluent principal l'Allier Catalogue méthodique et descriptif des vertébrés fossiles découverts dans le bassin hydrographique supérieur de la Loire, et surtout dans la vallée de son affluent principal l'Allier|publisher=J. B. Baillière|url=https://gallica.bnf.fr/ark:/12148/bpt6k97953010/f83}}</ref> In an 1839–1864 osteography, Blainville listed ''Palaeotherium'' species previously recognized by other taxonomists and erected ''P. girondicum''.<ref name="osteography"/> In 1863, the French naturalist [[Jean-Baptiste Noulet]] created the species ''P. castrense'' based on an incomplete [[mandible]] from the commune of [[Viviers-lès-Montagnes]], where it was later studied in [[Castres]].<ref>{{cite journal|last=Noulet|first=Jean-Baptiste|year=1863|title=Etude sur les fossiles du terrain éocène supérieur de l’Agout (Tarn)|journal=Mémoires de l'Académie royale des sciences, inscriptions et belles-lettres de Toulouse|pages=181–206|series=6|volume=1|url=https://gallica.bnf.fr/ark:/12148/bpt6k5779143h/f200}}</ref> In 1869, Pictet and [[Aloïs Humbert|Humbert]] erected the species ''Plagiolophus siderolithicus'' using fossil molars from a museum collection whose form is similar to that of ''P. minor'' but differs mainly by the dimensions.<ref>{{cite book|last1=Pictet|first1=François Jules|last2=Humbert|first2=Aloïs Humbert|year=1869|title=Mémoire sur les animaux vertébrés: trouvés dans le terrain sidérolitique du Canton de Vaud et appartenant a la faune éocène: supplément|publisher=H. Georg|volume=2|url=https://www.biodiversitylibrary.org/item/112849#page/9/mode/1up}}</ref> The same year, German palaeontologist [[Oscar Fraas]] erected ''P. suevicum'' based on teeth that he thought to have distinct [[tooth enamel|enamel]].<ref>{{cite book|last=Fraas|first=Oscar|year=1869|title=Die geognostische sammlung Württembergs im erdgeschoss des Königlichen Naturalien-cabinets zu Stuttgart: Ein führer für die besucher derselben|publisher=Self-published|url=https://books.google.com/books/about/Die_geognostische_sammlung_W%C3%BCrttembergs.html?id=XAs5AAAAMAAJ}}</ref> Gervais in 1875 described fossil bones and teeth from the French commune of [[Dampleux]], noting that the particular species was smaller than others classified to ''Palaeotherium'' and that the dental measurements were similar to those of ''Plagiolophus minor''. He assigned the fossils to the newly erected species ''P. eocaenum''.<ref>{{cite journal|last=Gervais|first=Paul|year=1875|title=Palæothérium du calcaire grossier|journal=Journal de zoologie|pages=421–422|url=https://www.biodiversitylibrary.org/item/45079#page/440/mode/1up}}</ref>


=== ''Palaeotherium'' skeletons ===
{{multiple image
| align = right
| image1= Palaeotherium magnum skeleton vitry sur seine.jpg
| image2= Palaeotherium magnum skeleton mormoiron 1922.png
| total_width = 400
| total_height= 400
| footer = Illustrations of ''P. magnum'' skeletons from [[Vitry-sur-Seine]] (left) and [[Mormoiron]] (right)
}}
For much of paleontological history, ''Palaeotherium'' was not known by any complete skeleton since its initial description by Cuvier.<ref name="skeleton2">{{cite book|last=Roman|first=Frédéric|year=1922|title=Monographie de la faune de mammifères de Mormoiron (Vaucluse) ludien supérieur|publisher=Société géologique de France|url=https://patrimoine.sorbonne-universite.fr/fonds/item/2894-monographie-de-la-faune-de-mammiferes-de-mormoiron-vaucluse-ludien-superieur}}</ref> This changed when in 1873, the French geologist [[Gaston Casimir Vasseur]] uncovered the first complete skeleton of ''P. magnum'' from a gypsum quarry in the commune of [[Vitry-sur-Seine]].<ref name="paris">{{cite journal|last1=Thomas|first1=Gilles|last2=Vanara|first2=Nathalie|year=2016|title=Les carrières sous Paris et sa périphérie, une reconnaissance géopatrimoniale nécessaire|journal=Dynamiques Environnementales - Journal international des géosciences et de l'environnement|volume=37|pages=161–165|doi=10.4000/dynenviron.917}}</ref> The quarry was owned by the civil engineer Fuchs, who donated the skeleton to the National Museum of Natural History, France.<ref name="skeleton1">{{cite journal|last=Gervais|first=Paul|year=1873|title=Squelette de grand Paléothérium (''Palæotherium magnum'' de Cuvier): trouvé dans les platrières de Vitry-sur-Seine|journal=Journal de zoologie|volume=2|pages=520–523|url=https://www.biodiversitylibrary.org/item/44776#page/578/mode/1up}}</ref><ref name="skeleton1.5">{{cite book|last=Gaudry|first=Jean Albert|year=1888|title=Les ancêtres de nos animaux dans les temps géologiques|publisher=J. B. Baillière and Fils|url=https://www.biodiversitylibrary.org/item/101257#page/7/mode/1up}}</ref> The skeleton was first described by Gervais in an academic journal the same year, who noted that it allows for more accurate confirmations of the species' anatomical traits. He pointed out that the skeleton had a skull measures {{cvt|0.5|m}} long, a longer neck than previously expected, and a less stocky build compared to tapirs and rhinoceroses. The naturalist said that the extraction process was difficult but completed by multiple skillful workers.<ref name="skeleton1"/> Since then, it has been displayed at the [[Gallery of Paleontology and Comparative Anatomy]] exhibit of the museum, where it had been noted as an important and famous component of the gallery to the modern day.<ref name="skeleton1.5"/><ref name="paris"/>


During the 20th century, a second complete skeleton of ''P. magnum'' was excavated from the plasters within the French commune of [[Mormoiron]]. It was sent to the geological department of the [[University of Lyon]] and described after preparation by the Austrian geologist [[Frédéric Roman]] in 1922. Roman depicted a drawing of a reconstruction of the skeleton of ''P. magnum'' based on the Mormoiron skeleton within his 1922 monography. According to Austrian palaeontologist [[Othenio Abel]] in 1923, it was the most complete skeleton of ''Palaeotherium'' to have been found and amongst the most complete of early Cenozoic mammal skeletons, missing only a few ribs and a left [[femur]].<ref name="skeleton2"/><ref name="skeleton2.5">{{cite journal|last=Abel|first=Othenio|year=1923|title=Die Rekonstruktion von ''Palaeotherium magnum'' Cuvier|journal=Palaeontologische Zeitschrift|volume=6|pages=14–24|doi=10.1007/BF03041530}}</ref>


=== 20th century revisions ===
== Research history ==
=== Early history ===
{{multiple image
| align = right
| image1= Palaeotherium curtum and eocaenum dentition.jpg
| image2= Palaeotherium lautricense skull reconstruction.jpg
| total_width = 400
| total_height= 400
| footer = Illustrations of the dentition of ''P. curtum'' and ''P. eocaenum'' (left) and a reconstructed skull of ''P. lautricense'' (right)
}}
In 1904, Swiss palaeontologist [[Hans Georg Stehlin]] first created the species name ''P. lautricense'' based on an upper jaw from a collection at the Muséum de Toulouse that originated from sandstone deposits at Castres. He also wrote about two somewhat crushed skulls of the species, producing a sketched reconstruction of it based on the first one.<ref>{{cite journal|last=Stehlin|first=Hans Georg|year=1904|title=Sur les mammifères des Sables bartoniens du Castrais|journal=Bulletin de la Société géologique de France|series=4|volume=4|pages=445–475|url=https://www.biodiversitylibrary.org/item/96943#page/527/mode/1up}}</ref> In his monography for palaeotheres, published the same year, Stehlin considered most species within ''Palaeotherium'' to be potentially valid and created more of them, but he noted that most taxonomists were cautious invalidating species erected by Cuvier. Stehlin also revised ''P. girondicum'' as ''P. magnum var. girondicum'', or ''P. magnum girondicum''. He established the subspecies name ''P. curtum var. perrealense'', or ''P. curtum perrealense'', based on jaw fragments from La Débruge. He erected ''P. Mühlbergi'' based on dental material in the Swiss municipality of [[Obergösgen]] that Ruetimeyer examined back in 1862. He also stated that the recent excavations at Mormont from [[Natural History Museum of Basel]] had yielded fossils that he classified along with a mandible identified by Pictert in 1869 under the new species name ''P. Renevieri''. Finally, he also determined that an additional species ''Palaeotherium Rütimeyeri'', which he described as having primitive premolars, was present in the municipality of [[Egerkingen]].<ref>{{cite journal|last=Stehlin|first=Hans Georg|year=1904|title= Die Säugetiere des schweizerischen Eocaens. Critisher Catalog der Materialen. Zweiter Teil: Palaeotherium. — Plagiolophus. — Propalaeotherium|journal=Abhandlungen der schweizerischen paläontologischen Gesellschaf|volume=31|url=https://www.biodiversitylibrary.org/item/262221#page/1/mode/1up}}</ref>

[[File:Palaeotherium crassum lower jaw illustration.jpg|thumb|left|upright=0.85|Lower jaw of ''P. crassum'' from the French locality of La Débruge with a mostly complete dental set]]
In 1917, French palaeontologist [[Charles Depéret]] recognized two additional species of ''Palaeotherium'' called ''P. Euzetense'' and ''P. Stehlini''.<ref>{{cite book|last=Depéret|first=Charles|year=1917|title=Monographie de la faune de mammifères fossiles du Ludien inférieur d'Euzet-les-Bains (Gard)|publisher=Lyon A. Rey|url=https://www.biodiversitylibrary.org/item/112216#page/132/mode/1up}}</ref> German palaeontologist [[Wilhelm Otto Dietrich]] named the German species ''P. Kleini'' in 1922, basing it off of fossils from the locality of [[Mähringen]] and mentioning that it would have been the size of ''P. curtum'' and ''P. Heimi''.<ref>{{cite journal|last=Dietrich|first=Wilhelm Otto|year=1922|title=Beitrag zur Kenntnis der säugetierführenden Bohnerzformation in Schwaben. 1. Ein vergessenes, neu erschlossenes Höhlenvorkommen terrestrischen Eozäns auf der Ulmer Alb.|journal=Zentralblatt für Mineralogie, Geologie und Paläontologie|volume=19|pages=209–224}}</ref>

In 1968, upcoming German palaeontologist [[Jens Lorenz Franzen]], then a graduate student, made major revisions of ''Palaeotherium'' within his dissertation. He synonymized or rendered dubious statuses many species of ''Palaeotherium'' that were erected throughout the 19th and early 20th centuries, including those named by Cuvier. He also erected ''P. pomeli'' using fossils from a locality in Castres and reclassified "''Plagiolophus''" ''siderolithicum'' into ''Palaeotherium''. Furthermore, Franzen converted some species into subspecies, namely ''P. magnum girondicum'', ''P. magnum stehlini'', ''P. medium suevicum'', and ''P. medium euzetense''. In addition, he named the following subspecies that he named in his thesis: ''P. castrense robiacense'', ''P. crassum robustum'', ''P. curtum villerealense'', ''P. curtum frohnstettense'', ''P. muehlbergi praecursum'', and ''P. duvali priscum''. Not all species within ''Palaeotherium'' had any recognized subspecies in them.<ref name="revisions"/>

In 1975, Spanish palaeontologist María Lourdes Casanovas-Cladellas erected the species ''P. crusafonti'' from a left [[maxilla]] with dentition from the Spanish site of [[Roc de Santa]].<ref>{{cite journal|last=Casanovas-Cladellas|first=María Lourdes|title=Datos sobre los Perisodáctilos del yacimiento de Roc de Santa; la nueva especie Palaeotherium crusafonti|journal=Acta Geológica Hispánica|volume=10|issue=3|pages=121–126|url=https://digital.csic.es/handle/10261/7301}}</ref> In 1980, both she and José-Vicente Santafé-Llopis established the second Iberian species ''P. franzeni'', taking into account morphological differences of the dental fossils from the Spanish municipality of [[Sossís]].<ref>{{cite journal|last1= Casanovas-Cladellas|first1=María Lourdes|last2=Santafé-Llopis|first2=José Vicente|year=1980|title=El Palaeotherium de talla grande (Palaeotheriidae, Perissodactyla) del yacimiento ludiense de Sossís (Tremp, Lérida)|journal=Butlletí Informatiu, Institut de Paleontologia de Sabadell|volume=12|issue=1–2|pages=21–29}}</ref> In 1985, the French palaeontologist Jean-Albert Remy named a subspecies ''P. muehlbergi thaleri'' in honor of fellow palaeontologist Louis Thaler, having documented that its fossils were from the commune of [[Saint-Étienne-de-l'Olm]] and that both the [[holotype]] and [[paratype]] each consist of a skull with a mandible.<ref>{{cite journal|last=Remy|first=Jean-Albert|year=1985|title=Nouveaux gisements de mammifères et reptiles dans les Grès de Célas (Eocène sup. du Gard). Etude des Palaeotheriidés (Perissodactyla, Mammalia)|journal=Palaeontographica. Abteilung A, Paläozoologie, Stratigraphie|volume=189|number=4–6|pages=171–225|url=https://www.researchgate.net/publication/273505702_Nouveaux_gisements_de_mammiferes_et_reptiles_dans_les_Gres_de_Celas_Eocene_sup_du_Gard_Etude_des_Palaeotheriides_Perissodactyla_Mammalia}}</ref>

In 1991, Casanovas-Cladellas and Santafé-Llopis erected ''P. llamaquiquense'' from partial jaw material from the Spanish locality of Llamaquique in the city of [[Oviedo]], where the name derived from.<ref>{{cite journal|last1=Casanovas-Cladellas|first1=María Lourdes|last2=Santafé-Llopis|first2=José-Vicente|year=1991|title=Los Paleotéridos (Mammalia, Perissodactyla) del yacimiento de Llamaquique:(Oviedo, España)|journal=Boletín de Ciencias de la Naturaleza|volume=41|pages=101–195}}</ref> The next year in 1992, Remy proposed the creation of two subgenera of ''Palaeotherium'' based on cranial characteristics. The first subgenus he listed was ''Palaeotherium'', which includes the type species ''P. magnum'' along with ''P. medium'', ''P. crassum'', ''P. curtum'', ''P. castrense'', ''P. siderolithicum'', and ''P. muehlbergi''. The second subgenus name that he proposed was ''Franzenitherium'', which includes the type species ''P. lautricense'' plus ''P. duvali'' and was named in honor of Franzen's review of ''Palaeotherium''.<ref name="franzenitherium">{{cite journal|last=Remy|first=Jean-Albert|year=1992|title=Observations sur l'anatomie cranienne du genre Palaeotherium (Perissodactyla, Mammalia): mise en évidence d'un nouveau sous-genre, Franzenitherium|journal=Palaeovertebrata|volume=21|number=3–4|pages=103–224|url=https://www.researchgate.net/publication/273459309_Observations_sur_l%27anatomie_cranienne_du_genre_Palaeotherium_Perissodactyla_Mammalia_mise_en_evidence_d%27un_nouveau_sous-genre_Franzenitherium}}</ref> The Spanish palaeontologist Miguel Ángel Cuesta Ruiz-Colmenares established the species ''P. giganteum'' using dentition from the [[Mazaterón]] site in the [[Duero Basin]] in 1993, considering it to be the largest species of ''Palaeotherium'' known.<ref name="giganteum">{{cite journal|last=Ruiz-Colmenares|first=Miguel Ángel Cuesta|year=1993|title=Los Palaeotheriidae (Perissodactyla, Mammalia) del Eoceno de la Cuenca del Duero (Castilla y León, España)|journal=Estudios Geológicos|volume=49|number=1–2|pages=87–109|doi=10.3989/egeol.93491-2341}}</ref> In 1998, Casanovas-Cladellas et al. formally recognized ''P. crassum sossissense'' from a fragmented right maxilla with dentition from Sossís in Spain. They also invalidated the previously named ''P. franzeni'' due to reassigning the material to ''P. magnum stehlini''.<ref name="sossissense">{{cite book|editor-last1=Martinez|editor-first1=Nieves Lopez|editor-last2=Llovera|editor-first2=Jorge Civis|editor-last3=Casanovas-Cladellas|editor-first3=María Lourdes|editor-last4=Daams|editor-first4=Remmert|last1=Casanovas-Cladellas|first1=María Lourdes|last2=Soler|first2=Lluís Checa|last3=Santafé-Llopis|first3=José-Vicente|year=1998|title=Geología y Paleontología del Eoceno de la Pobla de Segur (Lleida)|chapter=Los perisodáctilos del yacimiento ludiense de Sossís (Cuenca Prepirenaica, Lleida, España)|publisher=University of Lleida, Institut d'Estudis Ilerdencs|pages=235–267}}</ref>

=== Classification ===
[[File:Georges Cuvier.png|thumb|Portrait of [[Georges Cuvier]], the French naturalist who described ''Palaeotherium'' and ''Anoplotherium'' in 1804]]
''Palaeotherium'' is the type genus of the Palaeotheriidae, largely considered to be one of two major [[hippomorph]] families in the superfamily [[Equoidea]], the other being the [[Equidae]]. Alternatively, some authors have proposed that equids are more closely related to the [[Tapiromorpha]] than to the Palaeotheriidae. It is also usually thought to consist of two families, the [[Palaeotheriinae]] and [[Pachynolophinae]]; not all authors agree on the latter as a palaeotheriid subfamily, however.<ref name="yunnan">{{cite journal|last=Bai|first=Bin|year=2017|title=Eocene Pachynolophinae (Perissodactyla, Palaeotheriidae) from China, and their palaeobiogeographical implications|journal=Palaeontology|volume=60|issue=6|pages=837–852|doi=10.1111/pala.12319}}</ref> Some authors have also considered the Plagiolophinae to be a separate subfamily, while others group its genera into the Palaeotheriinae.<ref name="thrace">{{cite journal|last1=Métais|first1=Grégoire|last2=Sen|first2=Sevket|year=2017|title=First occurrence of Palaeotheriidae (Perissodactyla) from the late–middle Eocene of eastern Thrace (Greece)|journal=Comptes Rendus Palevol|volume=16|issue=4|pages=382–396|doi=10.1016/j.crpv.2017.01.001|bibcode=2017CRPal..16..382M |doi-access=free}}</ref> The geographic range of the palaeotheres were in contrast to equids, which are generally thought to have been an endemic radiation in North America. Some of the most basal equoids of the European landmass are of uncertain affinities, with some genera being thought to potentially belong to the Equidae.<ref name="hippomorph">{{cite journal|last1=Bronnert|first1=Constance|last2=Métais|first2=Grégoire|year=2023|title=Early Eocene hippomorph perissodactyls (Mammalia) from the Paris Basin|journal=Geodiversitas|volume=45|number=9|pages=277–326|doi=10.5252/geodiversitas2023v45a9|url=https://sciencepress.mnhn.fr/en/periodiques/geodiversitas/45/9}}</ref> Palaeotheriids are well-known for having lived in western Europe during much of the Palaeogene but were also present in eastern Europe, possibly the Middle East, and, in the case of pachynolophines (or pachynolophs), Asia.<ref name="yunnan"/><ref name="thrace"/>

The Perissodactyla makes its earliest known appearance in the European landmass in MP7 of the [[Mammal Paleogene zones|Mammal Palaeogene zones]]. During the temporal unit, many genera of basal equoids such as ''[[Hyracotherium]]'', ''[[Pliolophus]]'', ''[[Cymbalophus]]'', and ''[[Hallensia]]'' made their first appearances there. A majority of the genera persisted to the MP8-MP10 units, and "pachynolophines" (probably true palaeotheres) such as ''[[Propalaeotherium]]'' and ''[[Orolophus]]'' arose by MP10.<ref name="hippomorph"/><ref>{{cite journal|last1=Bronnert|first1=Constance|last2=Gheerbrant|first2=Emmanuel|last3=Godinot|first3=Marc|last4=Métais|first4=Grégoire|year=2017|title=A primitive perissodactyl (Mammalia) from the early Eocene of Le Quesnoy (MP7, France)|journal=Historical Biology|volume=30|issue=1–2|pages=237–250|doi=10.1080/08912963.2017.1341502|url=https://www.researchgate.net/publication/318400964_A_primitive_perissodactyl_Mammalia_from_the_early_Eocene_of_Le_Quesnoy_MP7_France}}</ref> The MP13 unit saw the appearances of later pachynolophines such as ''[[Pachynolophus]]'' and ''[[Anchilophus]]'' along with definite records of the first palaeotheriines such as ''Palaeotherium'' and ''[[Paraplagiolophus]]''.<ref name="iberian">{{cite journal|last1=Badiola|first1=Ainara|last2=Perales-Gogenola|first2=Leire|last3=Astibia|first3=Humberto|last4=Suberbiola|first4=Xabier Pereda|year=2022|title=A synthesis of Eocene equoids (Perissodactyla, Mammalia) from the Iberian Peninsula: new signs of endemism|journal=Historical Biology|volume=34|issue=8|pages=1623–1631|doi=10.1080/08912963.2022.2060098|bibcode=2022HBio...34.1623B |s2cid=248164842 }}</ref> The palaeotheriine ''Plagiolophus'' has been suggested to have potentially made an appearance by MP12. It was by MP14 that the subfamily proceeded to diversify,<ref name="aumelas">{{cite journal|last1=Remy|first1=Jean A.|last2=Krasovec|first2=Gabriel|last3=Lopez|first3=Éric|last4=Marandat|first4=Bernard|last5=Lihoreau|first5=Fabrice|year=2019|title=The Palaeotheriidae (Equoidea, Perissodactyla, Mammalia) from the Eocene fauna of Aumelas (Hérault department, France)|journal=Geodiversitas|volume=41|number=1|pages=525–585|doi=10.5252/geodiversitas2019v41a13}}</ref> and the plagiolophines were generally replaced but still reached the late Eocene. In addition to more widespread palaeothere genera such as ''Plagiolophus'', ''Palaeotherium'', and ''[[Leptolophus]]'', some of their species reaching medium to large sizes, various other palaeothere genera that were endemic to the Iberian penninsula, such as ''[[Cantabrotherium]]'', ''[[Franzenium]]'' and ''[[Iberolophus]]'', appeared by the middle Eocene.<ref name="iberian"/>

The phylogenetic tree for several members of the family Palaeotheriidae within the order Perissodactyla (including three outgroups) as created by Remy in 2017 and followed by Remy et al. in 2019 is defined below:<ref name="propachynolophus">{{cite journal|last=Remy|first=Jean A.|year=2017|title=Critical comments on the genus Propachynolophus Lemoine, 1891 (Mammalia, Perissodactyla, Equoidea)|journal=Palaeovertebrata|volume=41|pages=1–18|doi=10.18563/pv.41.1.e3}}</ref><ref name="aumelas"/>

{{clade
|1={{clade
|1={{clade
|1=''[[Cardiolophus|Cardiolophus radinskyi]]''
|2=''[[Hallensia|Hallensia matthesi]]''
}}
|2=''[[Pliolophus|Pliolophus vulpiceps]]''
|label3=[[Palaeotheriidae]]
|3={{clade
|1=''[[Hyracotherium|Hyracotherium leporinum]]''
|2={{clade
|1=''"Hyracotherium" levei''
|2={{clade
|1=''"Hyracotherium" remyi''
|2={{clade
|1=''[[Orolophus|Orolophus maldani]]''
|2={{clade
|label1=''[[Pachynolophus]]''
|1={{clade
|1={{clade
|1=''P. sp.'' AUM
|2=''P. duvali''
}}
|2={{clade sequential
|1=''P. ruscassierensis''
|2=''P. eulaliensis''
|3=''P. livinierensis''
|4=''P. cesserasicus''
}}
}}
|2={{clade
|1={{clade
|2=''[[Propalaeotherium|Propalaeotherium hassiacum]]''
|1={{clade
|2=''[[Eurohippus|Eurohippus parvulus]]''
|label1=''[[Lophiotherium]]''
|1={{clade
|1=''L. sp.'' AUM
|2=''L. pygmaeum''
|3=''L. cervulum''
}}
}}
}}
|2={{clade sequential
|1=''[[Propalaeotherium|Propalaeotherium cf. gaudryi]]'' AUM
|2=''[[Propalaeotherium|Propalaeotherium gaudryi]]''
|3=''[[Propalaeotherium|Propalaeotherium sudrei]]''
|4={{clade
|1=''[[Propalaeotherium|Propalaeotherium isselanum]]''
|label2=[[Palaeotheriinae]]
|2={{clade sequential
|1=''[[Leptolophus|Leptolophus nouleti]]''
|2=''[[Plagiolophus (mammal)|Plagiolophus minor]]''
|3=''[[Palaeotherium|Palaeotherium magnum]]''
}}
}}
}}
}}
}}
}}
}}
}}
}}
}}
}}

As shown in the above phylogeny, the Palaeotheriidae is defined as a [[monophyletic]] clade, meaning that it did not leave any derived descendant groups in its evolutionary history. ''Hyracotherium'' ''sensu stricto'' (in a strict sense) is defined as amongst the first offshoots of the family and a member of the Pachynolophinae. "''H.''" ''remyi'', formerly part of the now-invalid genus ''Propachynolophus'', is defined as a sister taxon to more derived palaeotheriids. Both ''Pachynolophus'' and ''[[Lophiotherium]]'', defined as pachynolophines, are defined as monophyletic genera. The other pachynolophines ''[[Eurohippus]]'' and ''Propalaeotherium'' consistute a paraphyletic clade in relation to members of the derived and monophyletic subfamily Palaeotheriinae (''Leptolophus'', ''Plagiolophus'', and ''Palaeotherium''), thus making Pachynolophinae a paraphyletic subfamily clade.<ref name="propachynolophus"/>

=== List of lineages ===
Since 1968, many species of ''[[Palaeotherium]]'' have multiple defined subspecies due to taxonomic revisions conducted by Franzen involving new species plus subspecies erections and conversions of some species into subspecies that were accepted by subsequent authors. From his dissertation was he able to justify the subspecies by proof of various intraspecific variations.<ref name="revisions"/><ref>{{cite journal|last=Antunes|first=Miguel Telles|year=1992|title=Contributions to the Eocene palaeontology and stratigraphy of B eira Alta, Portugal. II - New Late Eocene mammalian remnants from Coja (Portugal) and the presence of Palaeotherium magnum Cuvier|journal=Ciências da Terra/Earth Sciences Journal|volume=11|pages=83–89|url=https://cienciasdaterra.novaidfct.pt/index.php/ct-esj/article/view/129}}</ref> The following table defines the species and subspecies of ''Palaeotherium'' and additional information about them:

{| class="wikitable sortable"
|+ Comparative table of ''Palaeotherium'' lineages<ref name="robiac">{{cite journal|last=Remy|first=Jean-Albert|year=2015|title=Les Périssodactyles (Mammalia) du gisement Bartonien supérieur de Robiac (Éocène moyen du Gard, Sud de la France)|journal=Palaeovertebrata|volume=39|number=1|pages=1—98|doi=10.18563/pv.39.1.e3}}</ref><ref name="franzenitherium"/><ref name="MP">{{cite book|last1=Aguilar|first1=Jean-Pierre|last2=Legendre|first2=Serge|last3=Michaux|first3=Jacques|year=1997|title=Actes du Congrès Bio-chroM'97. Mémoires et Travaux de l'EPHE Institut de Montpellier 21|chapter=Synthèses et tableaux de corrélations|publisher=École Pratique des Hautes Études-Sciences de la Vie et de la Terre, Montpellier|language=french|pages=769–850|url=https://www.researchgate.net/publication/286785439}}</ref><ref name="secundaria">{{cite journal|last1=Gagnaison|first1=Cyril|last2=Leroux
|first2=Jean-Jacques|year=2013|title=Un crâne de Diplobune secundaria Cuvier, 1822 de Saint-Capraise-d'Eymet (Dordogne)|journal=Symbioses|volume=29|pages=43–46|url=https://www.researchgate.net/publication/279186555}}</ref>
|-
! Lineage
! Proposed subgenus
! MP unit(s)
! Author(s) of taxon
! Taxon publication year
|-
| ''P. castrense castrense''
| ''Palaeotherium''
| 14, 16
| [[Jean-Baptiste Noulet|Noulet]]
| 1863
|-
| ''P. castrense robiacense''
| ''Palaeotherium''
| 16
| [[Jens Lorenz Franzen|Franzen]]
| 1968
|-
| ''P. crassum sossisense''
| ''Palaeotherium''
| 17
| Casanovas-Cladellas, Checa, and Santafé-Llopis
| 1998
|-
| ''P. crassum crassum''
| ''Palaeotherium''
| 19
| [[Georges Cuvier|Cuvier]]
| 1805
|-
| ''P. crusafonti''
| ''[[Incertae sedis]]''
| 17
| Casanovas-Cladellas
| 1975
|-
| ''P. curtum villerealense''
| ''Palaeotherium''
| 17, 18
| Franzen
| 1968
|-
| ''P. curtum curtum''
| ''Palaeotherium''
| 19
| Cuvier
| 1812
|-
| ''P. curtum frohnstettense''
| ''Palaeotherium''
| 20
| Franzen
| 1968
|-
| ''P. duvali priscum''
| ''Franzenitherium''
| 17
| Franzen
| 1968
|-
| ''P. duvali duvali''
| ''Franzenitherium''
| 19
| [[Auguste Pomel|Pomel]]
| 1853
|-
| ''P. eocaenum''
| ''Incertae sedis''
| 13, 14
| [[Paul Gervais|Gervais]]
| 1875
|-
| ''P. giganteum''
| ''Incertae sedis''
| 16
| Cuesta
| 1993
|-
| ''P. lautricense''
| ''Franzenitherium''
| 16
| [[Hans Georg Stehlin|Stehlin]]
| 1904
|-
| ''P. llamaquiquense''
| ''Incertae sedis''
| 16
| Casanovas-Cladellas & Santafé Llopis
| 1991
|-
| ''P. magnum stehlini''
| ''Palaeotherium''
| 17
| [[Charles Depéret|Depéret]]
| 1917
|-
| ''P. magnum girondicum''
| ''Palaeotherium''
| 18
| [[Henri Marie Ducrotay de Blainville|Blainville]]
| 1846
|-
| ''P. magnum magnum''
| ''Palaeotherium''
| 19, 20
| Cuvier
| 1804
|-
| ''P. medium euzetense''
| ''Palaeotherium''
| 17
| Depéret
| 1917
|-
| ''P. medium perrealense''
| ''Palaeotherium''
| 18
| Stehlin
| 1904
|-
| ''P. medium medium''
| ''Palaeotherium''
| 19
| Cuvier
| 1804
|-
| ''P. medium suevicum''
| ''Palaeotherium''
| 20, 21
| [[Oscar Fraas|Fraas]]
| 1869
|-
| ''P. muehlbergi praecursum''
| ''Palaeotherium''
| 17
| Franzen
| 1968
|-
| ''P. muehlbergi thaleri''
| ''Palaeotherium''
| 18
| Remy
| 1985
|-
| ''P. muehlbergi muehlbergi''
| ''Palaeotherium''
| 19, 20
| Stehlin
| 1904
|-
| ''P. pomeli''
| ''Incertae sedis''
| 16
| Franzen
| 1968
|-
| ''P. renevieri''
| ''Incertae sedis''
| 19
| Stehlin
| 1904
|-
| ''P. ruetimeyeri''
| ''Incertae sedis''
| 14, 16
| Stehlin
| 1904
|-
| ''P. siderolithicum''
| ''Palaeotherium''
| 16, 17, 18, 19
| [[François Jules Pictet de la Rive|Pictet]] & [[Aloïs Humbert|Humbert]]
| 1869
|}

== Description ==
=== Skull ===
{{multiple image
{{multiple image
| align = left
| align = left
| image1= Annales du Muséum d'histoire naturelle (1804) (18410876301).jpg
| image1= Palaeotherium medium montmatre cuvier.JPG
| image2= Palaeotherium curtum tete.JPG
| image2= Palaeotherium minus Plagiolophus minor skeleton reconstruction.jpg
| total_width = 425
| total_height= 425
| footer = Montmartre skulls of ''P. medium'' (left) and ''P. curtum'' (right), [[National Museum of Natural History, France]]
}}
The Palaeotheriidae is diagnosed in part as generally having [[orbit (anatomy)|orbits]] that are wide open in the back area and are located in the middle of the skull or in a slight frontal area of it. The [[nasal bone]]s are slightly extensive to very extensive in depth. ''Palaeotherium'' is characterized as having [[calvaria (skull)|calvaria]] that range in base length from {{cvt|150|mm}} to {{cvt|520|mm}} depending on the species. The [[pterygoid crest]], which is located on the [[pterygoid processes of the sphenoid|pterygoid processes of the sphenoid bone]], does not cover the [[optic foramen]], which is separated from other cranial cavities at the [[temporal fossa]]. The [[zygomatic process]] of the [[squamosal bone]] is elongated and extends to the maxilla at a back angle of the orbit. The genus is also diagnosed by the presence of an [[anastomosis]] (anatomical connection between two passageways) roughly at the [[sphenoid bone]] and prominent [[temporalis muscle]] developments.<ref name="revisions"/><ref name="franzenitherium"/>

According to Remy, the subgenus ''Palaeotherium'' is the more specialized one of the two, characterized by the orbit being located more in front of the skull's middle length. The optic foramen is separated by a bony wall, and there are two [[optic canal]]s in total. The [[cranium]] is constricted in its front area behind the [[postorbital process]]es and close to the suture for the [[frontal bone]] and [[parietal bone]]. The other subgenus ''Franzenitherium'' in comparison has more generalized skull traits, its orbit being aligned within the middle length of the head. It has a front constriction of the cranium near the postorbital processes, and the optic foramen crosses through the skull from one side to the other. Not all species are placed in any subgenus due to having inadequate skull evidence for further analyses.<ref name="franzenitherium"/>

{{multiple image
| align = right
| image1= Palaeotherium magnum skull.JPG
| image2= Palaeotherium crassum montmartre.JPG
| total_width = 475
| total_height= 475
| footer = Montmartre skulls of ''P. magnum'' (left) and ''P. crassum'' (right), National Museum of Natural History, France
}}
The height and weight proportions of the skull of ''Palaeotherium'' are roughly equivalent with those of other taxa within the Equoidea. In comparison to other equoids where the skull's maximum width extends above the front root of the parallel [[zygomatic arch]]es, those of ''Palaeotherium'' and most other palaeotheres (except ''Leptolophus'') extend back to the joint of the squamosal bone and [[mandible]]. Unlike that of ''Plagiolophus'', the [[maxillary hiatus]], or an opening of the [[maxillary sinus]], in ''Palaeotherium'' is wide, diamond-shaped, and has oblique back edges. ''Palaeotherium'' differs from most other palaeotheres by the nasal opening stretching up to the P<sup>3</sup> tooth at minimum (noticeable in ''P. duvali'' and ''P. siderolithicum'') or up to the front edge of the orbit above M<sup>3</sup> in the case of ''P. magnum''. Similar to other palaeotheres, the back [[process (anatomy)|process]] (tissue projection) of the [[premaxilla]] is reduced, but its morphology can vary. The maxilla can extend to the nasal opening but can also vary in proportions. While the shapes and proportions of the nasal bones vary by species, they extend beyond P<sup>1</sup> in adults and sometimes even the [[canine tooth|canine]] like in [[equine]]s. The nasomaxillary suture, which unites the maxilla and nasal bones, is short and strongly curved.<ref name="franzenitherium"/>

The [[jugal bone]] and [[lacrimal bone]], both located in front of the orbit, are weak in development. The latter bone is elongated in its back and touches the posterolateral process of the nasal bones. Members of the Equoidea have relatively shortened front areas of the face. The orbits of ''Palaeotherium'', unlike those of other equoids, are proportionally smaller and are situated somewhat in front of the skull's mid-length area; they might be more forwards in the case of ''P. medium''. Similar to other Palaeogene equoids, the front edge of the orbit is aligned with M<sup>1</sup> or M<sup>2</sup> while the back area is wide. In most species, the [[infraorbital foramen]] in adults is located above P<sup>4</sup> or M<sup>1</sup>; in ''P. curtum frohnstettense'', it extends to above M<sup>2</sup>. Each zygomatic arch is wide, and its uneven narrowing in the front area under the orbit may be the result of either species traits or [[sexual differentiation]]. The squamosal process of the [[postorbital bone|postorbital]] is elongated and reaches the maxilla at a back angle of the orbital floor, the roof of the maxillary sinus. The orbit is shallow within its front area, its back opening of the [[infraorbital canal]] having a small distance of {{cvt|10|mm}} to {{cvt|15|mm}}. The canal itself is smaller than those of most other palaeotheriines except for that of ''Leptolophus'', and it has a tendency to shorten in later species.<ref name="franzenitherium"/>

{{multiple image
| align = left
| image1= Palaeotherium curtum skull 7.JPG
| image2= Palaeotherium medium-Montmatre-Paris-France-b.tif
| total_width = 500
| total_width = 500
| total_height= 500
| total_height= 500
| footer = 1804 sketch of a skeleton of "''[[Palaeotherium]] minus''" (= ''Plagiolophus minor'') from the commune of [[Pantin]] (left) and an 1812 drawn skeletal reconstruction based on the Pantin skeleton and additional fossil material by [[Georges Cuvier]] (right)
| footer = Cranium of ''P. curtum'' (left) and mandible of ''P. medium'' (right), National Museum of Natural History, France
}}
}}
In 1804, the French naturalist [[Georges Cuvier]], having established the genus ''[[Palaeotherium]]'' and some of its species (''P. medium'' and ''P. magnum''), recognized a third species ''P. minus'' based on some postcranial fossils from the gypsum quarries of the outskirts of Paris (known as the Paris Basin), although he did not elaborate further on them.<ref>{{cite journal|last=Cuvier|first=Georges|year=1804|title=Suite des Recherches: Suite de recherches sur les os fossiles de la pierre à plâtre des environs de Paris. Troisième mémoire. Restitution des pieds. Première section. Restitution des différens pieds de derrière.|journal=Annales du Muséum National d'Histoire Naturelle, Paris|language=french|volume=3|pages=442–472|url=https://www.biodiversitylibrary.org/item/51193#page/1/mode/1up|archive-date=2023-07-27|archive-url=https://web.archive.org/web/20230727022652/https://www.biodiversitylibrary.org/item/51193#page/1/mode/1up|url-status=live}}</ref> In a later journal of the same year, he described a nearly completely skeleton from the quarries of the [[communes of France|French commune]] of [[Pantin]], originally found by the French naturalist [[Auguste Nicholas de Saint-Genis]]. According to Cuvier, the quarry workers previously thought the skeleton to be of a ram, and it was presented as such in public newspapers. The French prefect [[Nicolas Frochot]] later acquired it and brought it to the [[National Museum of Natural History, France]], where Cuvier was then able to observe that it must have been a skeleton of a ''Palaeotherium'' species. He noted that the majority of the fossil bones were detached from others and/or damaged but that postcranial fossils such as [[scapula]]e, [[humeri]], [[femur]]s, [[vertebrae]], and [[rib]]s were found. The naturalist also provided a figure of the skeleton within the journal.<ref>{{cite journal|last=Cuvier|first=Georges|year=1804|title=Suite de recherches sur les os fossiles de la pierre à plâtre des environs de Paris. Cinquiéme Mémoire. Sur les os du Tronc. Premiére Section. Description d'un squelette presque entier trouvé dans les carriéres de Pantin|journal=Annales du Muséum National d'Histoire Naturelle, Paris|language=french|volume=4|pages=66–81|url=https://www.biodiversitylibrary.org/item/51194#page/76/mode/1up}}</ref>
The side wall of the snout is usually concave but may be interrupted by other local concavities that are normally poorly distinguished. The [[palatine bone]] has a well-developed front area, which in the case of ''P. curtum villerealense'' can rise near the orbit's top. The [[sphenopalatine foramen]], large and oval-shaped, is above the back of M<sup>4</sup>. The optic canal is small, has a primitive form of opening in front of the pterygoid crest, and is separated from it by a thick bony wall except in the cases of ''P. lautricense'' and ''P. duvali''. Whereas there are two optic canals in most species that are nearly parallel of each other and separate in the end, there is only one long one in ''P. lautricense'' and possibly ''P. duvali''. The sphenoid bone's wings are well-developed in their backs, and a suture for the parietal and sphenoid bones separates the frontal bone from the squamosal bone. The postorbital processes of the frontal bone are not very elongated. The [[cranial vault]] is broad, domed, and wider than the overall skull. The maximum front narrowing of the cranium, with the exceptions of those of ''P. lautricense'' and ''P. duvali'', is set far back to roughly where the frontoparietal suture occurs. The skull's top peaks at the far back area, although this is not observed in ''P. lautricense''. The [[sagittal crest]] can be prominent and depends on the age and sex of the individual for development. The [[nuchal crest]], where the neck attaches to the head, is prominent and, except in ''P. lautricense'', extends outwards plus backwards past the [[occipital condyles]]. The [[temporal fossa]]e are large but vary in proportion. In ''Palaeotherium'' and not ''Plagiolophus'', the overall basicranium's axis is thick plus wide.<ref name="franzenitherium"/>

The horizontal ramus of the mandible is overall thick plus tall and has an elongated [[mandibular symphysis]], but the width and lower area morphology vary by species. It is wide in both the front and back areas and low compared to equines. The joint for the squamosal and mandible of ''Palaeotherium'' is low compared to those of ''Plagiolophus'' and ''Leptolophus''. The [[angular process]], located above the [[angle of the mandible]], is blocked from further expansion by the [[mandibular notch]] and is well-developed in its rear like in Palaeogene equids. The [[coronoid process of the mandible]], an upper eminence, is both broad in the front plus back and stocky. The [[condyloid process]], an upper process of the mandible, is transversely elongated and cylindrical in shape. Both the [[mandibular fossa|zygomatico-mandibular fossa]] and [[pterygoid fossa]] are prominent.<ref name="franzenitherium"/>

=== Dentition ===
Derived palaeotheres are generally diagnosed as having selenolophodont upper molars and selenodont lower molars that are mesodont, or medium-crowned, in height. The canines strongly protrude and are separated from the premolars by medium to long [[diastema]]ta and from the incisors by short ones in both the upper and lower dentition. The other teeth are paired closely with each other in both the upper and lower rows.<ref name="revisions"/> The [[dental formula]] of ''Palaeotherium'' is {{DentalFormula|upper=3.1.4.3|lower=3.1.4.3}} for a total of 44 teeth, consistent with the primitive dental formula for early-middle Palaeogene [[placental]] mammals.<ref name="karl">{{cite book|last=von Zittel|first=Karl Alfred|editor-last=Schlosser|editor-first=Max|year=1925|title=Text-Book of Paleontology. Volume III. Mammalia|publisher=Macmillan and Co. Limited|pages=179–180|url=https://www.biodiversitylibrary.org/item/125078#page/162/mode/1up}}</ref><ref>{{cite journal|last1=Lihoreau|first1=Fabrice|last2=Boisserie|first2=Jean-Renaud|last3=Viriot|first3=Laurent|last4=Brunet|first4=Michel|year=2006|title=Anthracothere dental anatomy reveals a late Miocene Chado-Libyan bioprovince|journal=Proceedings of the National Academy of Sciences|volume=103|issue=23|pages=8763–8767 |doi=10.1073/pnas.0603126103 |pmid=16723392 |pmc=1482652 |bibcode=2006PNAS..103.8763L |doi-access=free }}</ref> The post-canine diastemata of ''Palaeotherium'' are small. The premolars and preceding deciduous teeth both tend to have molarized forms and have newly developing hypocone cusps on them. The mesostyle cusp present in the molars thicken from M<sup>1</sup> to M<sup>3</sup>. The lingual lobes (or divisions) in the upper molars are closely aligned with the ectolophs (crests or ridges of upper molar teeth).<ref name="mazateron">{{cite journal|last1=Perales-Gogenola|first1=Leire|last2=Badiola|first2=Ainara|last3=Pereda-Suberbiola|first3=Xabier|last4=Astibia|first4=Humberto|year=2022|title=New Eocene fossil remains of Palaeotheriidae (Perissodactyla, Mammalia) from Mazaterón (Soria, Castile and Leon, Spain)|journal=Historical Biology|volume=34|issue=8|doi=10.1080/08912963.2021.2025363}}</ref> The ectolophs themselves are W-shaped, being made up of two articulated crescents.<ref name="karl"/>

The incisors are shovel-shaped and, like modern horses, are used for chewing at right angles in relation to their longitudinal axes. They have no cutting functions but instead are used for grasping food akin to how tweezers grasp items. The canines are proportionally large-sized and are dagger-shaped. They were probably not used for cutting or chewing food given how they are oriented. Instead, they were probably used for biting functions for self-defense and sexual selection.<ref name="construction">{{cite book|editor-last1=Mazin|editor-first1=J.M.|editor-last2=Salmon|editor-first2=E.|last=Franzen|first=Jens Lorenz|year=1982|title=Actes du Symposium paléontologique Georges Cuvier, Montbéliard - France, 1982: communications données à l'occasion du cent cinquantième anniversaire de la mort de Georges Cuvier, du 25 octobre au 28 octobre 1982, au Musée du Château|chapter=Das Gebiss der Gattung Palaeotherium Cuvier 1804 Morphologie und Konstruktion|publisher=Le Musée du Château|pages=197–207}}</ref>

=== Postcranial skeleton ===

=== Footprints ===

== Palaeobiology ==

== Palaeoecology ==

== Extinction ==


In 1812, Cuvier published published his drawing of a skeletal reconstruction of ''P. minus'' based on known fossil remains of the species including the mostly complete skeleton. He also suggested theoretical lifestyles of several ''Palaeotherium'' species. In particular, he suggested that ''P. minus'' resembled a tapir, was smaller than a sheep, and was cursorial based on the slender morphologies of its leg bones. Such a behaviour and small size would have differed from other species of ''Palaeotherium'', several of which according to Cuvier had stockier limb bone builds. He also identified that ''P. medium'', ''P. magnum'', ''P. minus'', ''P. crassum'', and ''P. curtum'' were all tridactyl, or three-toed.<ref name="research">{{cite book|last=Cuvier|first=Geoges|year=1812|title=Recherches sur les ossemens fossiles de quadrupèdes: où l'on rétablit les caractères de plusieurs espèces d'animaux que les révolutions du globe paroissent avoir détruites|chapter=Résumé général et rétablissement des Squelettes des diverses espèces|volume=3|language=french|publisher=Chez Deterville|url=https://www.biodiversitylibrary.org/item/123872#page/1/mode/1up|archive-date=2023-07-31|archive-url=https://web.archive.org/web/20230731200748/https://www.biodiversitylibrary.org/item/123872#page/1/mode/1up|url-status=live}}</ref><ref>{{cite book|last=Rudwick|first=Martin J. S.|year=1997|title=Georges Cuvier, Fossil Bones, and Geological Catastrophes: New Translations and Interpretations of the Primary Texts|chapter=Chapter 6: The Animals from the Gypsum Beds around Paris|publisher=University of Chicago Press}}</ref>
== Notes ==
{{Notelist}}


== References ==
== References ==

Latest revision as of 06:52, 14 August 2024

PrimalMustelid/sandbox
Temporal range: Middle Eocene–Early Oligocene
Plagiolophus skeleton
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Perissodactyla
Family: †Palaeotheriidae
Genus: †Plagiolophus
Pomel, 1847
Type species
†Palaeotherium minus
(= †Plagiolophus minor)
Cuvier, 1804
Other species
  • †P. ovinus Aymard, 1846
  • †P. annectens Owen, 1848
  • †P. fraasi von Meyer, 1852
  • †P. javali Filhol, 1877
  • †P. lugdunensis Depéret & Carrière, 1901
  • †P. cartailhaci Stehlin, 1904
  • †P. cartieri Stehlin, 1904
  • †P. oweni Depéret, 1917
  • †P. curtisi Hooker, 1986
  • †P. major Brunet & Jehenne, 1989
  • †P. ministri Brunet & Jehenne, 1989
  • †P. casasecaensis Cuesta, 1994
  • †P. mazateronensis Cuesta, 1994
  • †P. huerzeleri Remy, 2000
  • †P. ringeadei Remy, 2004
  • †P. mamertensis Remy, 2004








































Research history

[edit]

Early history

[edit]
1804 sketch of a skeleton of "Palaeotherium minus" (= Plagiolophus minor) from the commune of Pantin (left) and an 1812 drawn skeletal reconstruction based on the Pantin skeleton and additional fossil material by Georges Cuvier (right)

In 1804, the French naturalist Georges Cuvier, having established the genus Palaeotherium and some of its species (P. medium and P. magnum), recognized a third species P. minus based on some postcranial fossils from the gypsum quarries of the outskirts of Paris (known as the Paris Basin), although he did not elaborate further on them.[1] In a later journal of the same year, he described a nearly completely skeleton from the quarries of the French commune of Pantin, originally found by the French naturalist Auguste Nicholas de Saint-Genis. According to Cuvier, the quarry workers previously thought the skeleton to be of a ram, and it was presented as such in public newspapers. The French prefect Nicolas Frochot later acquired it and brought it to the National Museum of Natural History, France, where Cuvier was then able to observe that it must have been a skeleton of a Palaeotherium species. He noted that the majority of the fossil bones were detached from others and/or damaged but that postcranial fossils such as scapulae, humeri, femurs, vertebrae, and ribs were found. The naturalist also provided a figure of the skeleton within the journal.[2]

In 1812, Cuvier published published his drawing of a skeletal reconstruction of P. minus based on known fossil remains of the species including the mostly complete skeleton. He also suggested theoretical lifestyles of several Palaeotherium species. In particular, he suggested that P. minus resembled a tapir, was smaller than a sheep, and was cursorial based on the slender morphologies of its leg bones. Such a behaviour and small size would have differed from other species of Palaeotherium, several of which according to Cuvier had stockier limb bone builds. He also identified that P. medium, P. magnum, P. minus, P. crassum, and P. curtum were all tridactyl, or three-toed.[3][4]

References

[edit]
  1. ^ Cuvier, Georges (1804). "Suite des Recherches: Suite de recherches sur les os fossiles de la pierre à plâtre des environs de Paris. Troisième mémoire. Restitution des pieds. Première section. Restitution des différens pieds de derrière". Annales du Muséum National d'Histoire Naturelle, Paris (in French). 3: 442–472. Archived from the original on 2023-07-27.
  2. ^ Cuvier, Georges (1804). "Suite de recherches sur les os fossiles de la pierre à plâtre des environs de Paris. Cinquiéme Mémoire. Sur les os du Tronc. Premiére Section. Description d'un squelette presque entier trouvé dans les carriéres de Pantin". Annales du Muséum National d'Histoire Naturelle, Paris (in French). 4: 66–81.
  3. ^ Cuvier, Geoges (1812). "Résumé général et rétablissement des Squelettes des diverses espèces". Recherches sur les ossemens fossiles de quadrupèdes: où l'on rétablit les caractères de plusieurs espèces d'animaux que les révolutions du globe paroissent avoir détruites (in French). Vol. 3. Chez Deterville. Archived from the original on 2023-07-31.
  4. ^ Rudwick, Martin J. S. (1997). "Chapter 6: The Animals from the Gypsum Beds around Paris". Georges Cuvier, Fossil Bones, and Geological Catastrophes: New Translations and Interpretations of the Primary Texts. University of Chicago Press.
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