Skull of Ptilodus mediaevus, copyright Nobu Tamura.

Belongs within: Cimolodonta.

The Ptilodontoidea are a group of multituberculate mammals known from the Upper Cretaceous to the Eocene of Eurasia and North America, characterised by a very large, arcuate lower rear premolar protruding dorsally above the level of the molars (Kielan-Jaworowska & Hurum 2001).

Characters (from Kielan-Jaworowska & Hurum 2001): Dental formula; enamel usually microprismatic (gigantoprismatic in Cimolodon); I2 probably single-cusped, I3 placed on margin of premaxilla; lower incisor usually gracile, completely covered with enamel (robust with limited enamel band in Neoliotomus); P4 elongated, shaped as isosceles triangle in lateral view, protruding ventrally over level of anterior premolars and molars; p4 very large, arcuate, strongly protruding dorsally over level of molars; molars with ornamentation of grooves and ridges, cusps tending to coalesce. Snout wide, gently incurved in front of zygomatic arches. Frontals small, pointed posteriorly.

    |    |--Anconodon Jepsen 1940K-JH01
    |    |--Liotomus Cope 1884K-JH01
    |    `--Cimolodon Marsh 1889K-JH01
    |         `--C. electusK-JH01
    `--+--Neoliotomus Jepsen 1930K-JH01
       |    `--N. ultimus Jepsen 1930SM93
       `--+--Ptilodontidae [Chirogidae]K-JH01
          |    |--Kimbetohia Simpson 1936K-JH01
          |    |--Prochetodon Jepsen 1940K-JH01
          |    |--Baiotomeus Krause 1987SFY02
          |    |    |--B. douglassi (Simpson 1935)SFY02
          |    |    |--B. lamberti Krause 1987SFY02
          |    |    `--B. russelli Scott, Fox & Youzwyshyn 2002SFY02
          |    `--Ptilodus Cope 1881SFY02
          |         |--P. douglassi Simpson 1935S35b
          |         |--P. fractus Dorr 1952SFY02
          |         |--P. gidleyi Simpson 1935S35b
          |         |--P. gnomus Scott, Fox & Youzwyshyn 2002SFY02
          |         |--P. kummae Krause 1977SFY02
          |         |--P. mediaevus Cope 1881SFY02
          |         |--P. montanus Douglass 1908 [incl. P. admirabilis Hay 1930, P. gracilis Gidley 1909 (preoc.)]S35b
          |         |--P. sinclairi Simpson 1935S35b
          |         |--P. trovessartianusS35b
          |         |--P. tsosiensis Sloan 1981SFY02
          |         `--P. wyomingensisD07
               |--Xyronomys Rigby 1980K-JH01
               |--Cernaysia Vianey-Liaud 1986K-JH01
               |--Krauseia Vianey-Liaud 1986K-JH01
               |--Mesodma Jepsen 1940K-JH01
               |--Mimetodon Jepsen 1940K-JH01
               |--Mesodmops Tong & Wang 1994K-JH01
               |--Xanclomys Rigby 1980K-JH01
               |--Neoplagiaulax Lemoine 1882K-JH01
               |    `--N. hazeniK-JH01
               |--Parectypodus Jepsen 1930K-JH01
               |    |--P. jepseni Simpson 1935S35b
               |    |--P. laytoniK-JH01
               |    |--P. simpsoniS35b
               |    `--P. tardusS35b
               `--Ectypodus Matthew & Granger 1921K-JH01
                    |--*E. musculus Matthew & Granger 1921S35a
                    |--E. cochranensisS35b
                    |--E. grangeri Simpson 1935S35b
                    |--E. lovei (Sloan 1966)S96
                    |--E. russelli Simpson 1935S35b
                    |--E. silberlingi Simpson 1935S35b
                    `--E. tardusK-JH01

*Type species of generic name indicated


[D07] Dixon, D. 2007. The Complete Illustrated Encyclopedia of Dinosaurs & Prehistoric Creatures. Hermes House: London.

[K-JH01] Kielan-Jaworowska, Z., & J. H. Hurum. 2001. Phylogeny and systematics of multituberculate mammals. Palaeontology 44 (3): 389–429.

[SFY02] Scott, C. S., R. C. Fox & G. P. Youzwyshyn. 2002. New earliest Tiffanian (late Paleocene) mammals from Cochrane 2, southwestern Alberta, Canada. Acta Palaeontologica Polonica 47: 691–704.

[S35a] Simpson, G. G. 1935a. The Tiffany fauna, Upper Paleocene. I.—Multituberculata, Marsupialia, Insectivora, and ?Chiroptera. American Museum Novitates 795: 1–19.

[S35b] Simpson, G. G. 1935b. New Paleocene mammals from the Fort Union of Montana. Proceedings of the United States National Museum 83 (2981): 221–244.

[S96] Storer, J. E. 1996. Eocene-Oligocene faunas of the Cypress Hills Formation, Saskatchewan. In: Prothero, D. R., & R. J. Emry (eds) The Terrestrial Eocene–Oligocene Transition in North America pp. 240–261. Cambridge University Press.

[SM93] Stucky, R. K., & M. C. McKenna. 1993. Mammalia. In: Benton, M. J. (ed.) The Fossil Record 2 pp. 739–771. Chapman & Hall: London.

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