Palaeanodonta

Palaeanodonta Temporal range: 62.4–30.9  Ma PreꞒ Ꞓ O S D C P T J K Pg N Middle Paleocene – Early Oligocene
From top to bottom: Ernanodon antelios , Xenocranium pileorivale and Metacheiromys marshi
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Mirorder:	Ferae
Clade:	Pholidotamorpha
Order:	† Palaeanodonta Matthew, 1918 [1]
Families and genera
[see classification]
Synonyms
list of synonyms: Ernodonta (Ding, 1987) [2] Ernanodonta (Ding, 1987) Palaeanodontidae (Carroll, 1988) [3] Palaeanodontiformes (Kinman, 1994) [4] Palaenodonta (Rose, 2008) [5] Palaenodontina (Pearse, 1936) [6]

Palaeanodonta ("ancient toothless animals") is an extinct order of placental mammals in the clade Pholidotamorpha. They were insectivorous (myrmecophagous), fossorial or semifossorial, and lived from the middle Paleocene to early Oligocene in North America, Europe and Asia. ^{[5] [7] [8]} While the taxonomic grouping of Palaeanodonta has been debated, ^[9] it is widely thought that they are a sister group to pangolins. ^{[10] [11] [7] [12]}

Anatomy

Skull

Palaeanodonts generally have low and caudally-broad skulls, with notable lambdoid crests and inflated bullae and squamosals. ^[5]

Teeth

Despite the name of the group and contrary to their pangolin relatives, palaeanodonts are known to have had teeth. ^{[13] [5] [12]} Early palaeanodonts retained minimal tribosphenic post-canines while later species had peglike or otherwise reduced molar crowns. ^{[13] [5] [12]} Many also had large, characteristic cuspids. ^{[13] [12]}

Classification and phylogeny

Former classification:

Current classification:

Order: †Palaeanodonta(Matthew, 1918) (stem-pangolins) Family: †Epoicotheriidae (paraphyletic family)(Simpson, 1927) Family: †Escavadodontidae (Rose & Lucas, 2000) Family: †Metacheiromyidae (Wortman, 1903) Incertae sedis : Genus: † Arcticanodon (Rose, 2004) Genus: † Melaniella (Fox, 1984)

Order: †Palaeanodonta(Matthew, 1918) (stem-pangolins) Family: † Epoicotheriidae (paraphyletic family)(Simpson, 1927) Genus: † Alocodontulum (Rose, 1978) †Alocodontulum atopum(Rose, 1977) Genus: † Amelotabes (Rose, 1978) †Amelotabes simpsoni(Rose, 1978) Genus: † Auroratherium (Tong & Wang, 1997) †Auroratherium sinense(Tong & Wang, 1997) Genus: † Dipassalus (Rose, 1991) †Dipassalus oryctes(Rose, 1991) Genus: † Myrmecoboides (Gidley, 1915) †Myrmecoboides arenarius(Secord, 2008) †Myrmecoboides montanensis(Gidley, 1915) Genus: † Tubulodon (Jepsen, 1932) †Tubulodon taylori(Jepsen, 1932) Subfamily: † Epoicotheriinae (paraphyletic subfamily)(Simpson, 1927) Genus: † Pentapassalus (Gazin, 1952) †Pentapassalus pearcei(Gazin, 1952) †Pentapassalus woodi(Guthrie, 1967) Genus: † Tetrapassalus (Simpson, 1959) †Tetrapassalus mckennai(Simpson, 1959) †Tetrapassalus proius(West, 1973) †Tetrapassalus sp. A [AMNH 10215] (Rose, 1978) †Tetrapassalus sp. B (Robinson, 1963) (unranked): †Epoicotherium/Xenocranium clade Genus: † Epoicotherium (Simpson, 1927) †Epoicotherium unicum(Douglass, 1905) Genus: † Molaetherium (Storch & Rummel, 1999) †Molaetherium heissigi(Storch & Rummel, 1999) Genus: † Xenocranium (Colbert, 1942) †Xenocranium pileorivale(Colbert, 1942) Family: † Ernanodontidae (Ting, 1979) Genus: † Asiabradypus (Nessov, 1987) †Asiabradypus incompositus(Nessov, 1987) Genus: † Ernanodon (Ting, 1979) †Ernanodon antelios(Ting, 1979) Family: † Escavadodontidae (Rose & Lucas, 2000) Genus: † Escavadodon (Rose & Lucas, 2000) †Escavadodon zygus(Rose & Lucas, 2000) Family: † Metacheiromyidae (paraphyletic family) [8] (Wortman, 1903) Genus: † Brachianodon (Gunnell & Gingerich, 1993) †Brachianodon westorum(Gunnell & Gingerich, 1993) Genus: † Mylanodon (Secord, 2002) †Mylanodon rosei(Secord, 2002) Subfamily: † Metacheiromyinae (paraphyletic subfamily) [8] (Wortman, 1903) Genus: † Metacheiromys (Wortman, 1903) †Metacheiromys dasypus(Osborn, 1904) †Metacheiromys marshi(Wortman, 1903) Genus: † Palaeanodon (Matthew, 1918) †Palaeanodon ignavus(Matthew, 1918) †Palaeanodon nievelti(Gingerich, 1989) †Palaeanodon parvulus(Matthew, 1918) †Palaeanodon sp. [Le Quesnoy] (Gheerbrant, 2005) Subfamily: † Propalaeanodontinae (Schoch, 1984) Genus: † Propalaeanodon (Rose, 1979) †Palaeanodon parvulus(Rose, 1979) Incertae sedis : Genus: † Arcticanodon (Rose, 2004) †Arcticanodon dawsonae(Rose, 2004) Genus: † Melaniella (Fox, 1984) †Melaniella timosa(Fox, 1984)

Phylogeny

Based on Rose (2000.) study: [13]	Based on Rose (2008.) study: [5]	Based on Kondrashov & Agadjanian (2012.) study: [8]
Scandentia   Tupaia † Leptictidae Erinaceomorpha † Pantolestidae   Pholidota    † Escavadodontidae   † Escavadodon †Palaeanodonta	† Pantolesta   † Pantolestidae  †Palaeanodonta   † Escavadodontidae   † Escavadodon † Amelotabes † Epoicotherium † Xenocranium † Tetrapassalus † Dipassalus † Alocodontulum † Pentapassalus † Tubulodon  ?  † Arcticanodon † Metacheiromyidae † Propalaeanodon † Mylanodon † Brachianodon † Metacheiromys † Palaeanodon † Epoicotheriidae	Eulipotyphla   Erinaceus   Carnivora   Nandinia   Pholidotamorpha   Pholidota  †Palaeanodonta  † Palaeanodon † Metacheiromys  † Ernanodontidae   † Ernanodon † Metacheiromyidae

See also

• Mammal classification
• Pholidotamorpha

References

1. W. D. Matthew (1918.) "A revision of the Lower Eocene Wasatch and Wind River faunas. Part V. Insectivora (Continued), Glires, Edentata." Bulletin of the American Museum of Natural History 38(16):429-483
2. S.-Y. Ding (1987). "A Paleocene edentate from the Nanxiong Basin, Guangdong". Palaeontologia Sinica. 173: 1–118.
3. Carroll, Robert L. (1988). Vertebrate Paleontology and Evolution (PDF). New York: W. H. Freeman and Company. pp. 1–698. ISBN   978-0-7167-1822-2.
4. Kenneth E. Kinman (1994.) "The Kinman system: toward a stable cladisto-eclectic classification of organisms: living and extinct, 48 phyla, 269 classes, 1,719 orders"
5. Rose, K. D. (2008). "9. Palaeanodonta and Pholidota". In Janis, C. M.; Gunnell, G. F.; Uhen, M. D. (eds.). Evolution of Tertiary Mammals of North America. Cambridge University Press. pp. 135–146. doi:10.1017/CBO9780511541438.010.
6. Arthur Sperry Pearse (1936.) "Zoological names. A list of phyla, classes, and orders, prepared for section F, American Association for the Advancement of Science" American Association for the Advancement of Science
7. Gaudin, T. J.; Emry, R. J.; Wible, J. R. (2009). "The Phylogeny of Living and Extinct Pangolins (Mammalia, Pholidota) and Associated Taxa: A Morphology Based Analysis". Journal of Mammalian Evolution. 16: 235. doi:10.1007/s10914-009-9119-9.
8. Kondrashov, Peter; Agadjanian, Alexandre K. (2012). "A nearly complete skeleton of Ernanodon (Mammalia, Palaeanodonta) from Mongolia: morphofunctional analysis". Journal of Vertebrate Paleontology. 32 (5): 983–1001. doi:10.1080/02724634.2012.694319. ISSN   0272-4634.
9. Averianov, A. O. & Lopatin, A. V. (2014.) "High-level systematics of placental mammals: Current status of the problem." Biology Bulletin, 41(9), 801–816.
10. McKenna, M. C.; Bell, S. K. (1997). Classification of Mammals: Above the Species Level. Columbia University Press. pp. 220–221. ISBN   978-0-231-52853-5.
11. Rose, K. D.; Emry, R. J.; Gaudin, T. J.; Storch, G. (2005). "Xenarthra and Pholidota". In Rose, K. D.; Archibald, J. D. (eds.). The Rise of Placental Mammals. Origins and Relationships of the Major Extant Clades. Johns Hopkins University Press. pp. 106–126. ISBN   978-0-8018-8022-3.
12. Ungar, P. S. (2010). "Cenozoic Mammal Evolution". Mammal Teeth: Origin, Evolution, and Diversity. pp. 110–126. ISBN   978-0-8018-9668-2.
13. Rose, K. D.; Lucas, S. G. (2000). "An early Paleocene palaeanodont (Mammalia, ?Pholidota) from New Mexico, and the origin of Palaeanodonta". Journal of Vertebrate Paleontology. 20 (1): 139–156. doi:10.1671/0272-4634(2000)020[0139:AEPPMP]2.0.CO;2.