Palaeanodonta

Palaeanodonta
Temporal range: Middle Paleocene – Early Oligocene
From top to bottom: Ernanodon antelios, Xenocranium pileorivale and Metacheiromys marshi
Scientific classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Clade: Pholidotamorpha
Order: †Palaeanodonta
Matthew, 1918
Families and genera
[see classification]
Synonyms
list of synonyms:
  • Ernodonta (Ding, 1987)
  • Ernanodonta (Ding, 1987)
  • Palaeanodontiformes (Kinman, 1994)
  • Palaenodonta (Rose, 2008)
  • Palaenodontina (Pearse, 1936)

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.

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

Traditional classification

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:

 Ferae 

Pan-Carnivora

 Pholidotamorpha 

Pholidota (sensu stricto)

 †Palaeanodonta 

†Escavadodontidae

 ? 

†Melaniella

†Amelotabes

†Epoicotheriidae

†Epoicotherium

†Molaetherium

†Xenocranium

†Epoicotheriinae

†Tetrapassalus

†Dipassalus

†Alocodontulum

†Auroratherium

†Pentapassalus

†Tubulodon

 ? 

†Arcticanodon

†Propalaeanodontinae

†Mylanodon

†Brachianodon

†Palaeanodon

†Metacheiromyinae 

†Metacheiromys

†Ernanodontidae

 (Pholidota sensu lato) 
†Epoicotherium/Xenocranium clade

See also