Palaeanodonta ("ancient toothless animals") is an extinct clade of stem-
pangolins. They were
insectivorous, possibly
fossorial, and lived from the Early
Paleocene
The Paleocene, ( ) or Palaeocene, is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era. The name is a combination of the Ancient Greek ''pal ...
to Early
Oligocene in
North America,
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...
and
East Asia
East Asia is the eastern region of Asia, which is defined in both Geography, geographical and culture, ethno-cultural terms. The modern State (polity), states of East Asia include China, Japan, Mongolia, North Korea, South Korea, and Taiwan. ...
.
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
Pangolins, sometimes known as scaly anteaters, are mammals of the order Pholidota (, from Ancient Greek ϕολιδωτός – "clad in scales"). The one extant family, the Manidae, has three genera: ''Manis'', ''Phataginus'', and ''Smutsia'' ...
.
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
* Order: †Palaeanodonta
(Matthew, 1918) (stem-pangolins)
** Family: †
Epoicotheriidae
Epoicotheriidae ("strange beasts") is an extinct family of insectivorous mammals which were endemic to North America from the early Eocene to the early Oligocene 55.8—30.9 Ma existing for approximately . Epoicotheriids were highly specialized ...
(Simpson, 1927)
** Family: †
Escavadodontidae
(Rose & Lucas, 2000)
** Family: †
Metacheiromyidae (Wortman, 1903)
** ''
Incertae sedis
' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertain ...
'':
*** Genus: †''
Amelotabes''
(Rose, 1978)
*** Genus: †''
Arcticanodon''
(Rose, 2004)
*** Genus: †''
Melaniella''
(Fox, 1984)
Revised classification
* Order: †Palaeanodonta
(Matthew, 1918) (stem-pangolins)
** Family: †
Epoicotheriidae
Epoicotheriidae ("strange beasts") is an extinct family of insectivorous mammals which were endemic to North America from the early Eocene to the early Oligocene 55.8—30.9 Ma existing for approximately . Epoicotheriids were highly specialized ...
(Simpson, 1927)
*** Genus: †''
Alocodontulum''
(Rose, 1978)
**** †''Alocodontulum atopum''
(Rose, 1977)
*** Genus: †''
Auroratherium''
(Tong & Wang, 1997)
**** †''Auroratherium sinense''
(Tong & Wang, 1997)
*** Genus: †''
Dipassalus''
(Rose, 1991)
**** †''Dipassalus oryctes''
(Rose, 1991)
*** Genus: †''
Pentapassalus''
(Gazin, 1952)
**** †''Pentapassalus pearcei''
(Gazin, 1952)
**** †''Pentapassalus woodi''
(Guthrie, 1967)
*** Genus: †''
Tubulodon''
(Jepsen, 1932)
**** †''Tubulodon taylori''
(Jepsen, 1932)
*** Subfamily: †
Epoicotheriinae (Simpson, 1927)
**** Genus: †''
Epoicotherium''
(Simpson, 1927)
***** †''Epoicotherium unicum''
(Douglass, 1905)
**** Genus: †''
Molaetherium''
(Storch & Rummel, 1999)
***** †''Molaetherium heissigi''
(Storch & Rummel, 1999)
**** Genus: †''
Tetrapassalus''
(Simpson, 1959)
***** †''Tetrapassalus mckennai''
(Simpson, 1959)
***** †''Tetrapassalus proius''
(West, 1973)
**** 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)
*** Genus: †''
Brachianodon''
(Gunnell & Gingerich, 1993)
**** †''Brachianodon westorum''
(Gunnell & Gingerich, 1993)
*** Genus: †''
Mylanodon''
(Secord, 2002)
**** †''Metacheiromys dasypus''
(Secord, 2002)
*** Subfamily: †
Metacheiromyinae (paraphyletic subfamily)
**** 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)
*** Subfamily: †
Propalaeanodontinae
(Schoch, 1984)
**** Genus: †''
Propalaeanodon''
(Rose, 1979)
***** †''Palaeanodon parvulus''
(Rose, 1979)
** ''
Incertae sedis
' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertain ...
'':
*** Genus: †''
Amelotabes''
(Rose, 1978)
**** †''Amelotabes simpsoni''
(Rose, 1978)
*** Genus: †''
Arcticanodon''
(Rose, 2004)
**** †''Arcticanodon dawsonae''
(Rose, 2004)
*** Genus: †''
Melaniella''
(Fox, 1984)
**** †''Melaniella timosa''
(Fox, 1984)
Phylogenetic tree
The phylogenetic relationships of Palaeanodonta are shown in the following cladogram:
References
{{Taxonbar, from=Q3889294
Fossil taxa described in 1918