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. While the taxonomic grouping of Palaeanodonta has been debated,Averianov, A. O. & Lopatin, A. V. (2014.) "High-level systematics of placental mammals: Current status of the problem." Biology Bulletin, 41(9), 801–816. it is widely thought that they are a sister group to pangolins.
Anatomy Skull Palaeanodonts generally have low and caudally-broad skulls, with notable lambdoid crests and inflated bullae and squamosals.
Teeth Despite the name of the group and contrary to their pangolin relatives, palaeanodonts are known to have had teeth. Early palaeanodonts retained minimal tribosphenic post-canines while later species had peglike or otherwise reduced molar crowns. Many also had large, characteristic cuspids.
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) (Wortman, 1903) Genus: †Brachianodon (Gunnell & Gingerich, 1993) †Brachianodon westorum (Gunnell & Gingerich, 1993) Genus: †Mylanodon (Secord, 2002) †Mylanodon rosei (Secord, 2002) Subfamily: †Metacheiromyinae (paraphyletic subfamily) (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 Cladogram of phylogeny within order Palaeanodonta Based on Rose (2000.) study: Based on Rose (2005.) study: Based on Rose (2008.) study: Based on Kondrashov & Agadjanian (2012.) study: Based on Hooker (2013.) study: Based on Rose (2026.) study:
See also Mammal classification Pholidotamorpha
References