Arctoidea is an

infraorder Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between Family_(biology), family and Class_(biology), class. In biological classification, the order is a taxonomic rank used in the classific ...

of mostly

carnivorous A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose nutrition and energy requirements are met by consumption of animal tissues (mainly mu ...

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

s which include the extinct

Hemicyonidae Hemicyoninae is an extinct subfamily of Ursidae, often called dog bears (literally "half dog" (Ancient Greek, Greek: )). They were bear-like carnivorans living in Europe, North America, Africa and Asia during the Oligocene through Miocene epoch ...

(dog-bears), and the extant

Musteloidea Musteloidea is a superfamily (taxonomy), superfamily of carnivoran mammals united by shared characteristics of the skull and teeth. Musteloids are the sister group of pinnipeds, the group which includes seals. Musteloidea comprises the following ...

(weasels, raccoons, skunks, red pandas),

Pinnipedia Pinnipeds (pronounced ), commonly known as seals, are a widely distributed and diverse clade of carnivorous, fin-footed, semiaquatic, mostly marine mammals. They comprise the extant families Odobenidae (whose only living member is the walrus), ...

(seals, sea lions), and

Ursidae Bears are carnivoran mammals of the family (biology), family Ursidae (). They are classified as caniforms, or doglike carnivorans. Although only eight species of bears are extant, they are widespread, appearing in a wide variety of habitats ...

(bears), found in all continents from the

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

, , to the present. The oldest group of the

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

is the bears, as their CMAH gene is still intact. The gene became non-functional in the common ancestor of the Mustelida (the musteloids and pinnipeds). Arctoids are

caniforms Caniformia is a suborder within the order Carnivora consisting of "dog-like" carnivorans. They include dogs (wolves, foxes, etc.), bears, raccoons, and mustelids. The Pinnipedia ( seals, walruses and sea lions) are also assigned to this gr ...

, along with dogs (canids) and extinct bear dogs (Amphicyonidae). The earliest caniforms were superficially similar to

martens A marten is a weasel-like mammal in the genus ''Martes'' within the subfamily Guloninae, in the family (biology), family Mustelidae. They have bushy tails and large paws with partially retractile claws. The fur varies from yellowish to dark bro ...

, which are tree-dwelling mustelids. Together with

feliforms Feliformia is a suborder within the order Carnivora consisting of "cat-like" carnivorans, including Felidae, cats (large and small), hyenas, mongooses, viverrids, and related taxa. Feliformia stands in contrast to the other suborder of Carnivora, ...

, caniforms compose the order

Carnivora Carnivora ( ) is an order of placental mammals specialized primarily in eating flesh, whose members are formally referred to as carnivorans. The order Carnivora is the sixth largest order of mammals, comprising at least 279 species. Carnivor ...

; sometimes Arctoidea can be considered a separate suborder from Caniformia and a sister taxon to Feliformia.

Systematics

Arctoidea was named by Flower (1869). It was reranked as the unranked clade Arctoidea by Hunt (2001), Hunt (2002) and Hunt (2002); it was reranked as the infraorder Arctoidea by Koretsky (2001), Zhai et al. (2003) and Labs Hochstein (2007). It was assigned to

by Flower (1883), Barnes (1987), Barnes (1988), Carroll (1988), Barnes (1989), Barnes (1992), Hunt (2001), Hunt (2002) and Hunt (2002); and to Caniformia by Tedford (1976), Bryant (1991), Wang and Tedford (1992), Tedford et al. (1994), Koretsky (2001), Zhai et al. (2003), Wang et al. (2005), Owen (2006), Peigné et al. (2006) and Labs Hochstein (2007).J. Labs Hochstein. 2007. "A new species of Zodiolestes (Mammalia, Mustelidae) from the early Miocene of Florida". ''Journal of Vertebrate Paleontology'' 27(2):532–534

Phylogeny

The

cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...

is based on

molecular phylogeny Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

of six genes in Flynn (2005), with the musteloids updated following the multigene analysis of Law et al. (2018).

References

Eocene carnivorans Oligocene caniforms Miocene carnivorans Pliocene carnivorans Pleistocene carnivorans Extant Eocene first appearances {{paleo-carnivora-stub