Plionarctos
Encyclopedia
Plionarctos is an extinct genus
of mammal
s of the family Ursidae (bears) endemic to North America
and Europe
during Miocene
through Pleistocene
, living from ~10.3—3.3 Ma, existing for approximately .
Indarctos
(10.7—9.2 Ma) preceded Plionarctos by only a few thousand years and was a contemporary of that bear and shared its habitat. Plionarctus preceded and was also contemporary with Tremarctos floridanus (4.9 Ma.—11,000 years ago) and shared its habitat.
Plionarctos is the oldest known genus within the subfamily of the short-faced bears (Tremarctinae
) endemic to the Americas, and is believed to be ancestral to the clade
.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s of the family Ursidae (bears) endemic to North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
and Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
during Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
through Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
, living from ~10.3—3.3 Ma, existing for approximately .
Indarctos
Indarctos
Indarctos is a genus of mammals of the family Ursidae endemic to North America, Europe, Africa, and Asia during the Miocene, living from ~11.1—5.3 Ma, existing for approximately ....
(10.7—9.2 Ma) preceded Plionarctos by only a few thousand years and was a contemporary of that bear and shared its habitat. Plionarctus preceded and was also contemporary with Tremarctos floridanus (4.9 Ma.—11,000 years ago) and shared its habitat.
Plionarctos is the oldest known genus within the subfamily of the short-faced bears (Tremarctinae
Tremarctinae
Tremarctinae is a term for the subfamily of Ursidae containing one living representative, the Spectacled Bear of South America, and several extinct species from four genera: the Florida spectacled bear , the North American short-faced bears of genera Plionarctos and Arctodus Tremarctinae is a...
) endemic to the Americas, and is believed to be ancestral to the clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
.
Taxonomy
Plionarctos was named by Frick (1926). Its type is Plionarctos edensis. It was assigned to Ursidae by Frick (1926) and Carroll (1988); and to Tremarctini by Hunt (1998).Body mass
Two specimens were examined by Legendre and Roth for body mass.- Specimen 1 estimated to weigh: 165.5 kg (364.9 lb)
- Specimen 2 estimated to weigh: 25.3 kg (55.8 lb)
Fossil distribution
Sites and specimen ages:- Ile de Ratonneau Breccia, Provence, France ~800,000—100,000 years ago.
- Fort Green Mine, Polk County, Florida paleontological sitesPolk County, Florida paleontological sitesThe Polk County paleontological sites are assemblages of Early Miocene to Late Pleistocene vertebrates occurring in Polk County, Florida, United States.-Age:Era: Neogene...
~10.3—4.9 Ma. - Taunton site, Adams County, Washington (P. harroldorum) ~4.9—1.8 Ma. (Plionarctos harroldorum)
- Pipe Creek SinkholePipe Creek SinkholePipe Creek Sinkhole near Swayzee in Grant County, Indiana, is one of the most important paleontological sites in the interior of the eastern half of North America, due to preservation, and the exception from 'typical glacial strata mixing' from glaciation...
, Grant County, IndianaGrant County, IndianaGrant County is a county located in the U.S. state of Indiana. As of the 2010 census, the population was 70,061. The county seat is Marion. Important paleontological discoveries dating from the Pliocene epoch have been made at Pipe Creek Sinkhole in Grant County.-Geography:According to the 2010...
(P. edensis) ~10.3—1.8 Ma. - Palmetto Mine, Polk County, FloridaPolk County, FloridaPolk County is located in central Florida between the Tampa Bay and Greater Orlando metropolitan areas. The county was established by the state government in 1861 on the eve of the American Civil War and named after former United States president James K. Polk. The county seat is Bartow and its...
~7.9—7.8 Ma. - Gray Fossil SiteGray Fossil SiteThe Gray Fossil Site is a Late Miocene-epoch assemblage of fossils located near the unincorporated town of Gray in Washington County, Northeast Tennessee, and dates from 7 to 4.5 million years BCE). The Gray Fossil Site was discovered by geologists in May 2000...
, Washington County, Tennessee ~7.0-4.5 Ma.