Palaeanodonta

Palaeanodonta ("ancient toothless animals") is an extinct clade of stem-pangolins. They were insectivorous (myrmecophagous), possibly fossorial, and lived from the middle Paleocene to early Oligocene in North America, Europe and Asia. While the taxonomic grouping of Palaeanodonta has been debated, it is widely thought that they are a sister group to pangolins.

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.

Traditional 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)

Revised classification

 * 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: †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)

Phylogenetic tree
The phylogenetic relationships of order Palaeanodonta are shown in the following cladogram: