Ailuropodinae is a subfamily of

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 ...

that contains only one extant species, the

giant panda The giant panda (''Ailuropoda melanoleuca''), also known as the panda bear or simply panda, is a bear species endemic to China. It is characterised by its white animal coat, coat with black patches around the eyes, ears, legs and shoulders. ...

(''Ailuropoda melanoleuca'') of China. The fossil record of this group has shown that various species of pandas were more widespread across the

Holarctic The Holarctic realm is a biogeographic realm that comprises the majority of habitats found throughout the continents in the Northern Hemisphere. It corresponds to the floristic Boreal Kingdom. It includes both the Nearctic zoogeographical reg ...

, with species found in places such as

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

, much of

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

and even

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

. The earliest pandas were not unlike other modern bear species in that they had an omnivorous diet but by around 2.4 million years ago, pandas had evolved to be more herbivorous. The giant panda (''Ailuropoda'') belongs to the order of Carnivora, this means that the macronutrients that are digested are most similar to those of carnivores than to that of herbivores even though their diet consists mainly of bamboo.

Systematics

Ever since the giant panda was first described to science, they have been a source of taxonomic confusion, having been variously classified as a member of

Procyonidae Procyonidae ( ) is a New World family of the order Carnivora. It includes the raccoons, ringtails, cacomistles, coatis, kinkajous, olingos, and olinguitos. Procyonids inhabit a wide range of environments and are generally omnivorous. Ch ...

Ailuridae Ailuridae is a family in the mammal order Carnivora. The family consists of the red panda (the sole living representative) and its extinct relatives. Georges Cuvier first described ''Ailurus'' as belonging to the raccoon family in 1825; this ...

, or even their own family Ailuropodidae. Part of their similarities with the

red panda The red panda (''Ailurus fulgens''), also known as the lesser panda, is a small mammal native to the eastern Himalayas and southwestern China. It has dense reddish-brown fur with a black belly and legs, white-lined ears, a mostly white muzz ...

is in particular the presence of a "thumb" and five fingers; the "thumb" – a modified

sesamoid bone In anatomy, a sesamoid bone () is a bone embedded within a tendon or a muscle. Its name is derived from the Greek word for 'sesame seed', indicating the small size of most sesamoids. Often, these bones form in response to strain, or can be presen ...

– that helps it to hold bamboo while eating. Recent genetic studies have shown that ailuropodines are indeed members of the bear family as they are not closely related to red pandas, which are placed in their own family Ailuridae. Any similarities between ailuropodines and ailurids are likely due to

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last comm ...

as the fossil record has shown the "false thumb" has been required independently for different purposes. The "false thumb" has been found in

spectacled bear The spectacled bear (''Tremarctos ornatus''), also known as the South American bear, Andean bear, Andean short-faced bear or mountain bear and locally as jukumari ( Aymara and Quechua), ukumari ( Quechua) or ukuku, is a species of bear native to ...

s as well, suggesting that it is a

plesiomorphic In phylogenetics, a plesiomorphy ("near form") and symplesiomorphy are synonyms for an ancestral character shared by all members of a clade, which does not distinguish the clade from other clades. Plesiomorphy, symplesiomorphy, apomorphy, an ...

trait among bears that became lost in the

Ursinae Ursinae is a subfamily of Ursidae (bears) named by Swainson (1835). It was assigned to Ursidae by Bjork (1970), Hunt (1998), and Jin et al. (2007). Classification The genera '' Melursus'' and '' Helarctos'' are sometimes also included in ''Ur ...

subfamily.

Taxonomy

The ailuropodines are divided into two tribes the extinct Agriotheriini and Ailuropodini; the following taxonomy below is after Abella et al. (2012): * Subfamily Ailuropodinae Grevé, 1894 ** Tribe † Agriotheriini Kretzoi, 1929 *** †''

Agriotherium ''Agriotherium'' is an extinct genus of bears whose fossils are found in Miocene through Pleistocene-aged strata of North America, Eurasia, and Africa. The earliest species, ''A.'' ''aecuatorialis'' evolved during the early Late Miocene, around ...

'' Wagner, 1837 **** †''Agriotherium africanum'' Hendey, 1972 **** †''Agriotherium gregoryi'' Frick, 1926 **** †''Agriotherium hendeyi'' Jiangzuo & Flynn, 2019 **** †''Agriotherium inexpetans'' Qiu et al., 1991 **** †''Agriotherium insigne'' Gervais, 1859 **** †''Agriotherium myanmarensis'' Ogino et al., 2011 **** †''Agriotherium palaeindicus'' Lydekker, 1878 **** †''Agriotherium sivalensis'' (Falconer & Cautley, 1836) *** †''

Huracan Huracán (; ; , "one legged"), often referred to as ''U Kʼux Kaj'', the "Heart of Sky", is a Kʼicheʼ people, Kʼicheʼ Maya mythology, Maya god of wind, storm, fire and one of the creator deities who participated in all three attempts at crea ...

'' Jiangzuo et al., 2023 **** †''Huracan coffeyi'' (Dalquest, 1986) **** †''Huracan qiui'' Jiangzhou et al., 2023 **** †''Huracan schneideri'' (Sellards, 1916) **** †''Huracan? punjabensis'' (Lydekker, 1884) 'Indarctos punjabensis'' (Lydekker, 1884)**** †''Huracan? roblesi'' (Morales & Aguirre, 1976) 'Agriotherium roblesi'' Morales & Aguirre, 1976*** †''

Indarctos ''Indarctos'' is an extinct genus of bear, present in Africa, North America, and Eurasia during the Miocene. It was present from ~11.1 to 5.3 Annum, Ma, existing for approximately . The oldest member is from Arizona (~11.1—7.7 Ma) and youngest ...

'' Pilgrim, 1913 **** †''Indarctos anthracitis'' (Weithofer, 1888) **** †''Indarctos arctoides'' (Deperet, 1895) **** †''Indarctos atticus'' (Weithofer, 1888) **** †''Indarctos bakalovi'' (Kovachev, 1988) **** †''Indarctos lagrelli'' (Zdansky, 1924) **** †''Indarctos nevadensis'' Macdonald, 1959 **** †''Indarctos oregonensis'' Merriam et al., 1916 **** †''Indarctos salmontanus'' Pilgrim, 1913 **** †''Indarctos sinensis'' (Zdansky, 1924) **** †''Indarctos vireti'' Villalta & Crusafont, 1943 **** †''Indarctos zdanskyi'' Qiu & Tedford, 2003 *** ?†'' Miomaci'' de Bonis et al., 2017 **** †''Miomaci pannonicum'' de Bonis et al., 2017 ** Tribe Ailuropodini Grevé, 1894 *** '' Ailuropoda'' Milne-Edwards, 1870 **** '' Ailuropoda melanoleuca'' David, 1869 –

**** †'' Ailuropoda baconi'' Woodward 1915 **** †'' Ailuropoda microta'' Pei, 1962 **** †'' Ailuropoda wulingshanensis'' Wang & Alii, 1982 *** †'' Agriarctos'' Kretzoi, 1942 **** †''Agriarctos depereti'' (Schlosser, 1902) **** †''Agriarctos gaali'' Kretzoi, 1942 **** †'' Agriarctos nikolovi'' Jiangzuo & Spassov, 2022 **** †''Agriarctos vighi'' Kretzoi, 1942 *** †'' Ailurarctos'' Qi et al., 1989 **** †''Ailurarctos lufengensis'' Qi et al., 1989 **** †''Ailurarctos yuanmouensis'' Zong, 1997 *** †'' Kretzoiarctos'' Abella et al., 2012 **** †''Kretzoiarctos beatrix'' Abella et al., 2011

References

{{Taxonbar, from=Q17560554 Bears Extant Miocene first appearances