Tillodontia
Tillodontia Temporal range:Early Paleocene-Late Eocene
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Tillodonskull | |
Scientific classification![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Clade: | Paraxonia |
Order: | †Tillodontia Marsh 1875 |
Genera | |
See text |
Tillodontiais an extinct suborder ofeutherianmammals known from theEarly PaleocenetoLate Eoceneof China, theLate PaleocenetoMiddle Eoceneof North America where they display their maximum species diversity, theMiddle EoceneofPakistan,and the Early Eocene ofEurope.Leaving no descendants, they are most closely related to thepantodonts,another extinct group. The tillodonts were medium- to large-sized animals that probably fed on roots and tubers in temperate to subtropical habitats.[1]
Description[edit]
Tillodonts had rodent-like incisors, clawed feet and blunt, cusped teeth. They were mostly medium-sized animals, although the largest of them (such asTrogosus)could reach the size of a large bear.
The cranium ranged in length from 5 to 37 cm (2.0 to 14.6 in) and had a characteristic elongatedrostrum,an elongatedmandibular symphysis,and a shortened basicranial region. The second upper and lower incisors are large in most species, the first upper and lower premolars are small or absent, the fourth upper and lower premolars are molariform (molar-like).[1]
WhenMarshfirst named and described the tillodonts, he explained:[2]
These animals are among the most remarkable yet discovered in American strata, and seem to combine characters of several distinct groups, viz: Carnivores, Ungulates, and Rodents. InTillotheriumMarsh [=Trogosus], the type [specimen] of the order, the skull has the same general form as in the Bears, but its structure resembles that of Ungulates. The molar teeth are of the ungulate type, the canines are small, and in each jaw there is a pair of large scalpriform incisors faced with enamel, and growing from persistent pulps, as in Rodents.
When naming his new "pachyderm"speciesTrogosus castoridens( "beaver-toothed gnawing-hog" ), Leidy added that it was a fossil "which would appear to have pertained to the stock from which diverged the Rhinoceros and Mastodon, the Peccary, and perhaps the Beaver."[3]
Classification[edit]
Franchaiusfrom the early Eocene of Europe,Benaius,Lofochaius,Meiostylodon,andHuananiusfrom the early Paleocene of China, andYuesthonyxfrom the late Paleocene of China are primitive forms.Interogalefrom the late Paleocene of China, andAnchilestesprobably from the middle Paleocene of China, were once assigned toAnagalida,but may also be primitive tillodonts.[4]
The monophyly of the subfamilyTrogosinaeis unchallenged, butEsthonychinesmost likely includes the ancestors of Trogosinae and therefore is probably paraphyletic. Tillodontia is mostly known from dentaries and teeth. The cranium is best known from Trogosinae and the postcranium fromTrogosus.[5]
AzygonyxandEsthonyxfrom North America,FranchaiusandPlesiesthonyxfrom Europe, andBasalinafrom Pakistan are all morphologically closely related but obviously geographically quite widespread. In contrast, Asian tillodonts tend to be smaller and less derived. This possible link between specimens from Pakistan and Europe with those from North America adds evidence to a faunal interchange between these continents during the early Eocene.[6]
OrderTillodontia[7]
- Genus †Azygonyx(Gingerich 1989), dentary, postcranial fragments
- Genus †Basalina(Dehm & Oettingen-Spielberg 1958), poorly preserved jaw fragment with incomplete cheek tooth
- Genus †Benaius(Wang & Jin 2004), left lower jaw
- Genus †Chungchienia(Chow 1963),
- Genus †Dysnoetodon(Zhang 1980), maxilla and lower jaw
- Family †Esthonychidae(Cope 1883) (Syn. Anchippodontidae, Tillotheriidae)
- Genus †Adapidium(Young 1937), right lower jaw
- Subfamily †Esthonychinae(Zittel & Schlosser 1911)
- Genus †Megalesthonyx(Rose 1972), left mandible, teeth, feet bones
- Subfamily †Trogosinae(Gazin 1953) (Syn. Anchippodus)
- Genus †Tillodon(Gazin 1953), skull
- Genus †Trogosus(Leidy 1871) (Syn.Tillotherium), skull, lower jaws, teeth, vertebrae, ilium, limb bones, feet bones
- Genus †Franchaius(Baudry 1992;synonymized withPlesiesthonyx,Hooker 2010), less than 20 isolated teeth[6]
- Genus †Higotherium(Miyata & Tomida 1998),[8]fragmentary right mandible, teeth
- Genus †Interogale(Huang & Zheng 1983), well-preserved mandible
- Genus †Kuanchuanius(Chow 1963), partial mandible, teeth
- Genus †Lofochaius(Chow et al. 1973), poorly preserved skull with few teeth
- Genus †Meiostylodon(Wang 1975), three isolated teeth
- Genus †Plesiesthonyx(Lemoine 1891), isolated molars
- Genus †Plethorodon(Huang & Zheng 1987), partial skull with upper cheek teeth
- Genus †Simplodon(Huang & Zheng 2003), right upper jaw with cheek teeth
- Family †Yuesthonychidae(Tong, Wang & Fu 2003)
- Genus †Yuesthonyx(Tong, Wang & Fu 2003), left mandibles, partial skull, teeth
Notes[edit]
- ^abLucas & Schoch 1998,p. 268
- ^Marsh 1875,p. 221
- ^Leidy 1871,p. 115
- ^Rose 2006,p. 113
- ^Rose 2006,p. 111
- ^abRose et al. 2009,pp. 353–4
- ^Tillodontia: Relationshipsin thePaleobiology DatabaseRetrieved July 2013.
- ^"†Higotherium".Taxonomicon.Retrieved24 July2013.
References[edit]
- Baudry, Mylène (1992). "Les Tillodontes (Mammalia) de l'Eocène inférieur de France".Bulletin du Muséum National d'Histoire Naturelle, Section C.14(2): 205–243.
- Chow, Minchen M.(1963)."Tillodont Materials from Eocene of Shantung and Honan"(PDF).Vertebrata PalAsiatica(in Chinese and English).7(2): 97–104.Retrieved24 July2013.
- Chow, Minchen M.; Chang, Yu-ping; Wang, Ban-yue; Ting, Su-yin (1973)."New Mammalian Genera and Species from the Paleocene of Nanhsiung, N. Kwangtung"(PDF).Vertebrata PalAsiatica(in Chinese and English).11(1): 31–35.Retrieved24 July2013.
- Cope, E. D.(1874)."Report upon vertebrate fossils discovered in New Mexico, collected in 1874".InWheeler, George(ed.).Annual Report Upon the Geographical Explorations and Surveys West of the One Hundredth Meridian, in California, Nevada, Utah, Arizona, Colorado, New Mexico, Wyoming, and Montana, Appendix FF.Washington: Government Printing Office. pp. 118–120.Retrieved24 July2013.
- Cope, E. D. (1883)."On the mutual relations of the bunotherian Mammalia".Proceedings of the Academy of Natural Sciences of Philadelphia.35:77–83.Retrieved24 July2013.
- Dehm, Richard; Oettingen-Spielberg, Therese zu (1958).Paläontologische und geologische Untersuchungen im Tertiär von Pakistan. 2. Die mitteleocänen Säugetiere von Ganda Kas bei Basal in Nordwest-Pakistan.Abhandlungen / Neue Folge, 91. Munich: Beck.OCLC163296508.
- Gazin, C. L.(1953)."The Tillodontia: an early tertiary order of mammals".Smithsonian Miscellaneous Collections.121(10): 1–110.OCLC459282832.Retrieved24 July2013.
- Gingerich, P. D.(1989)."New earliest Wasatchian mammalian fauna from the Eocene of northwestern Wyoming: composition and diversity in a rarely sampled high-floodplain assemblage".University of Michigan Papers on Paleontology.28:1–97.hdl:2027.42/48628.Retrieved24 July2013.
- Hooker, J. J. (2010)."The mammal fauna of the early Eocene Blackheath Formation of Abbey Wood, London".Monograph of the Palaeontographical Society London.165(634): 1–162.Retrieved24 July2013.
- Huang, Xueshi; Zheng, Jia gian (1983)."A New Anagalid from Upper Paleocene of Nanxiong Basin, Guangdong"(PDF).Vertebrata PalAsiatica(in Chinese and English).21(1): 59–63.Retrieved24 July2013.
- Huang, Xueshi; Zheng, Jia gian (1987)."A New Pantodont-like mammal from the Paleocene of Chienshan Basin, Anhui"(PDF).Vertebrata PalAsiatica(in Chinese and English).25(1): 20–31.Retrieved24 July2013.
- Huang, Xueshi; Zheng, Jia gian (2003)."A tillodont-like mammal from the Middle Paleocene of Qianshan Basin, Anhui, China"(PDF).Vertebrata PalAsiatica.41(2): 131–136.Retrieved24 July2013.
- Leidy, J.(1871)."Remains of extinct mammals from Wyoming".Proceedings of the Academy of Natural Sciences.23:113–116.Retrieved24 July2013.
- Lemoine, M. (1891)."Étude d'ensemble sur les dents des mammifères fossiles des environs de Reims".Bulletin de la Société Géologique de France.3rd.19:263–290 (276).Retrieved24 July2013.
- Lucas, S. G.;Schoch, R. M.(1998). "Tillodontia". In Janis, Christine Marie; Scott, Kathleen Marie; Jacobs, Louis L. (eds.).Evolution of Tertiary Mammals of North America: Terrestrial carnivores, ungulates, and ungulatelike mammals.Cambridge University Press. pp.268–273.ISBN9780521355193.
- Marsh, O. C.(1875)."New Order of Eocene Mammals".American Journal of Science.9(280): 221.Bibcode:1875Natur..11R.368..doi:10.1038/011368b0.S2CID36028842.Retrieved24 July2013.
- Miyata, Kazunori; Tomida, Yukimitsu (1998)."A new tillodont from the early Middle Eocene of Japan and its implication to the subfamily Trogosinae (Tillodontia: Mammalia)"(pdf).Paleontological Research.2(1): 53–66.Retrieved24 July2013.
- Rose, Kenneth D. (1972)."A New Tillodont from the Eocene Upper Willwood Formation of Wyoming"(PDF).Postilla.155.Peabody Museum of Natural History.OCLC7337187.Retrieved24 July2013.
- Rose, Kenneth D. (2006).The beginning of the age of mammals.Baltimore: JHU Press.ISBN0801884721.
- Rose, Kenneth D.; Rana, Rajendra S.; Sahni, Ashok; Kumar, Kishor; Singh, Lachham; Smith, Thierry (2009)."First Tillodont from India: Additional Evidence for an Early Eocene Faunal Connection between Europe and India?".Acta Palaeontologica Polonica.54(2): 351–355.doi:10.4202/app.2008.0067.
- Tong, Yong-Sheng; Wang, Jing-Wen; Fu, Jing-Fang (2003)."Yuesthonyx,a new tillodont (Mammalia) from the Paleocene of Henan "(PDF).Vertebrata PalAsiatica.41(1): 55–65.Retrieved24 July2013.
- Wang, Ban-yue (1975)."Paleocene mammals of Chaling Basin, Hunan"(PDF).Vertebrata PalAsiatica(in Chinese).13(3): 154–162.Retrieved24 July2013.
- Wang, Y.-Q.; Jin, X. (2004)."A new Paleocene tillodont (Tillodontia, Mammalia) from Qianshan, Anhui, with a review of Paleocene tillodonts from China"(PDF).Vertebrata PalAsiatica(in English and Chinese).42(1): 13–26.Retrieved24 July2013.
- Young, C. C.(1937). "An early Tertiary vertebrate fauna from Yuanchü".Bulletin of the Geological Society of China.17(3–4): 413–438.doi:10.1111/j.1755-6724.1937.mp173-4012.x.
- Zhang, Yu-ping (1980)."A New Tillodont-Like Mammal from the Paleocene of Nanxiong Basin, Guangdong"(PDF).Vertebrata PalAsiatica(in Chinese and English).18(2): 126–30.Retrieved24 July2013.
- Zittel, K. A., von;Schlosser, M.(1911).Grundzüge der Paläontologie (Paläozoologie).Vol. 2. Vertebrata. Munich.OCLC312682921.
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