Indarctos (all species)

[Gorilla king]

Indarctos is an extinct genus of bear, endemic to North America, Europe and Asia during the Miocene. It was present from ~11.1 to 5.3 Ma, existing for approximately 6.2 million years.





Species

†I. punjabensis (Lydekker, 1884)
†I. zdanskyi (Qiu & Tedford, 2003)[1]
†I. sinensis (Zdansky, 1924)
†I. vireti (Villalta & Crusafont, 1943)
†I. arctoides (Deperet, 1895)
†I. anthracitis (Weithofer, 1888)
†I. salmontanus (Pilgrim, 1913)
†I. atticus (Weithofer, 1888)
†I. bakalovi (Kovachev, 1988)
†I. lagrelli (Zdansky, 1924)
†I. oregonensis (Merriam et al., 1916)
†I. nevadensis (Macdonald, 1959)[2]

The oldest member is from Arizona (~11.1—7.7 Ma) and youngest is (~9.0—5.3 Ma) from Kazakhstan. In North America this animal was contemporary with Plionarctos (~10.3—3.3 Ma).

Discovery, history and taxonomyEditDiscoveriesEdit

A molar (designated to MNA 1839/km-83) discovered from the Karabulak formation in 1988 was tentatively assigned to Indarctos sp. In 2017 it was re examined and assigned to I. punjabensis. The tooth was found to belong to a young individual, which might possibly be a male, and is the largest tooth known from this species.This might be due to sexual dimorphism since extant male bears are larger than the females.[3]

SpeciesEdit

Indarctos is known from several species spread widely across Eurasia, North America, and North Africa, however, most of them are known from fragmentary remains which leaves us with insufficient knowledge of the anatomy, lifestyle, taxonomy and paleoecology of some species. These species are usually established based on poor remains, where the presence of sexual dimorphism, paleogeographical variation and individual variation is not taken into account, resulting in a number of species whose taxonomic validity is doubted.

The following are some species of this genus:

I. arctoides: This species had a herbivorous diet, and it was ancestral to the later I. punjabensis.

I. punjabensis: This species is the geologically youngest and last species of Indarctos. It had a wide distribution 6.3–6.5 Ma during the Late Miocene, across Eurasia. It is known from the Karabulak formation of Kazakhstan,to China and the Dhon Pathan formation of Indo-Pakistan.[3] It descended from the earlier I. arctoides, but unlike its ancestor, it was omnivorous and bigger in size. Based on resemblance of its forelimbs to those of the modern brown bear, it possibly had similar locomotor adaptations, evolutionary features such as this led to the migration of Indarctos-like bears into North America. At the end of the Late Miocene, Indarctos punjabensis went extinct as the last species of its genus.


en.m.wikipedia.org/wiki/Indarctos

[Gorilla king]

PREHISTORIC FAUNA





Indarctos arctoides

Indarctos (Indarctos Pilgrim 1913)

 Order: Carnivora

Family: Ursidae

Genus: †Indarctos

Dimensions: length - 2 m, height - 130 сm, weight - 70 - 320 kg

Temporal range: Micene of North America, Europe, Africa, and Asia

 
Indarctos is a genus of mammals of the bear family, Ursidae, endemic to North America, Europe, Africa, and Asia during the Miocene. It was present from ~11.1 to 5.3 Ma, existing for approximately 6.2 million years. The oldest member is from Arizona (~11.1—7.7 Ma) and youngest is (~9.0—5.3 Ma) from Kazakhstan. In North America this animal was contemporary with Plionarctos (~10.3—3.3 Ma).

Indarctos was named by Pilgrim (1913) Its type is Indarctos salmontanus. It was assigned to Agriotheriini by Chorn and Hoffman (1978); to Ursavini by Hunt (1998); and to Ursidae by Pilgrim (1913), Carroll (1988) and Salesa et al. (2006).


prehistoric-fauna.com/Indarctos

[Gorilla king]

Size Mattered to Ancient Bear, Penis Bones Suggest




This diagram compares the size the shape of the penis bones of the following bear species: A) sun bear, B) Asian black bear, C) Andean bear, D) American black bear, E) sloth bear, F) brown bear, G) polar bear and H) the extinct Indarctos arctoides. (Image credit: PLOS ONE, doi:10.1371/journal.pone.0073711.g001)


Scientists don't have any footage to shed light on the sex lives of ancient bears, but fossil penis bones can tell all.

Researchers recently studied a collection of penis bones from an extinct species of bear in Spain. Compared with today's bears, this ancient creature, named Indarctos arctoides, had a surprisingly large penis bone that suggests it had infrequent but long-lasting sex sessions, the study found. And the females may have used penis size to assess their mates.

Human males today don't have a penis bone, formally called a bacula, but it is found in many other mammals, including chimpanzees and gorillas. Whereas humans depend on blood pressure to stiffen up their sexual member, a penis bone helps animals keep their penis reliably erect for intercourse. [7 Wild Facts About the Penis]

Penis bones are rare in the fossil record, but researchers found five of them in the Madrid Basin in Spain that belonged to this large primitive bear, Indarctos arctoides. The bear roamed Europe during the Late Miocene (around 12 million to 5 million years ago), and the male of the species would have grown to around 584 pounds (265 kilograms), similar in size to the European brown bear.

Its bacula was, on average, 9.1 inches (23.3 centimeters) long — significantly larger than the penis bones of much bigger bears. Male polar bears, the biggest bears on Earth today, typically weigh 1,100 lbs. (500 kg), but their penis bone averages about 7.3 inches (18.6 cm) long, the researchers say.

The length of the penis bone could reveal details not only about the sexual behavior of Indarctos arctoides, but also the species' ecological habits and mating system.

Based on the size of baculum, the researchers think the bear likely had fewer but longer periods of intercourse than other mammals. A long baculum, the study researchers say, could have served as a physical support during mating, helping to keep the female's reproductive tract open and in an optimal position for fertilization during these sporadic dalliances.

Indarctos arctoides may have also had relatively large individual ranges and possibly a lower population density, giving rise to fewer sexual encounters, the researchers say.

The fossil record shows that the male Indarctos arctoides would have been much larger than the female. Previous research has suggested bear species with strong sex differences tend to have shorter penis bones and mating systems where males take multiple mates and fiercely compete for females. The fact that Indarctos arctoides had a relatively long bacula suggests it was a sexually selected trait that females used to assess mate quality.

The study was led by paleobiologist Juan Abella, of the Autonomous University of Barcelona. It was detailed Sept. 18 in the journal PLOS ONE.


www.google.com/amp/s/www.livescience.com/amp/39895-ancient-bear-penis-bone.html

[Gorilla king]

Coexistence of Indarctos and Amphimachairodus (Carnivora) in the Late Early Hemphillian of Florida, North America


Abstract and Figures

Fossils of the ursid Indarctos from Withlacoochee River 4A of Florida (late early Hemphillian North American Land Mammal Age, Hh2, ~ 7.5–6.5 Ma) represent the best sample of this genus in North America, including both craniodental and postcranial specimens, yet only the skull has been described. In this study, we describe the other material of this bear from the same locality and review the records of Indarctos in North America. Indarctos from Withlacoochee River 4A has dental characters in accordance with those of typical Indarctos oregonensis, but has distinctly more slender postcranial bones. Indarctos from other localities of North America contains two morphs with regards to postcranial robustness, but lacks a clear geographic pattern. Indarctos from Withlacoochee River 4A shares traits with the Old World Indarctos zdanskyi and may be its descendant in the New World. The machairodont from Withlacoochee River 4A shows typical characters (e.g., presence of distinct P4 preparastyle and mandibular flange) that allow referral to Amphimachairodus rather than to Nimravides. Its morphology also shows a stronger affinity of this population to the Old World Amphimachairodus horribilis rather than to Hh3 Amphimachairodus coloradensis. Previously, most North American records of Amphimachairodus were late Hemphillian (Hh3–4, ~ 6.5–4.5 Ma), when it co-occurred with a different ursid, “Agriotherium.” The Withlacoochee River 4A specimens provide evidence that Amphimachairodus dispersed from Asia during the Hh2. The special morphology of Indarctos and the presence of Amphimachairodus in a Hh2 fauna suggest that the environment had begun to change before the significant fauna turnover between the early and late Hemphillian.


www.researchgate.net/publication/351851193_Coexistence_of_Indarctos_and_Amphimachairodus_Carnivora_in_the_Late_Early_Hemphillian_of_Florida_North_America

[Gorilla king]

Late Miocene Indarctos punjabiensis atticus (Carnivora, Ursidae) in Ukraine with survey of Indarctos records in the former USSR


.. The species of Indarctos were initially included in Hyaenarctos (later a synonym of Agriotherium), until Pilgrim (1913) noted the distinctiveness of this taxon and established a new genus. The number of species of Indarctos and their geographic distributions, however, are still debatable (Abella et al., 2014;Baryshnikov 2002;Qiu and Tedford 2003). This is partially caused by the incompleteness of the type species from the Siwaliks (location in Figure 1), i.e. ...

... Thenius (1959) believed that the difference in M2 talon length was not beyond expected infraspecific variation, and both Siwalik species were similar to the European species so could be assigned to I. atticus as the subspecies I. a. punjabiensis. Baryshnikov (2002) suggested that in this situation, this species instead should be called I. punjabiensis, since it has priority over I. atticus. A single species of Turolian and equivalent-aged Holarctic (or at least Palearctic) Indarctos (or possibly two species, adding I. anthracitis for some authors) were followed by most subsequent authors (Montoya et al. 2001;Baryshnikov 2002Baryshnikov , 2007Abella et al., 2014). ...

... Baryshnikov (2002) suggested that in this situation, this species instead should be called I. punjabiensis, since it has priority over I. atticus. A single species of Turolian and equivalent-aged Holarctic (or at least Palearctic) Indarctos (or possibly two species, adding I. anthracitis for some authors) were followed by most subsequent authors (Montoya et al. 2001;Baryshnikov 2002Baryshnikov , 2007Abella et al., 2014). Several authors (Qiu and Tedford 2003;Qi 2006), however, still considered the two Siwalik species to be distinct from each other, and distinct from European species. ...


www.researchgate.net/publication/306940303_Late_Miocene_Indarctos_punjabiensis_atticus_Carnivora_Ursidae_in_Ukraine_with_survey_of_Indarctos_records_in_the_former_USSR

[Gorilla king]

INDARCTOS OREGONENSIS LOWER JAW FOUND IN NEBRASKA. AROUND 15 INCHES:





museum.unl.edu/collections/vertebrate-paleontology/nebraska-county-fossils/frontier.html

[Gorilla king]

—Indarctos atticus, skull and mandible, NHMW-SAM-no 25, Loc. unknown, Samos Island, Turolian, MN 11-13.  







www.researchgate.net/figure/Indarctos-atticus-skull-and-mandible-NHMW-SAM-no-25-Loc-unknown-Samos-Island_fig2_257042588

[Gorilla king]

[Gorilla king]

In situ photograph showing the fossil remains of an almost articulated forepaw of Indarctos arctoides from Batallones-3 (BAT-3 ’ 09.870-882 and BAT-3 ’ 09.884-900) in anatomical connection. Scale bars equal 5 cm


www.researchgate.net/figure/n-situ-photograph-showing-the-fossil-remains-of-an-almost-articulated-forepaw-of_fig2_277719032