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Post by tyrannosaurs on Aug 3, 2021 6:00:25 GMT -5
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Post by Gorilla king on Aug 3, 2021 6:44:26 GMT -5
Remember that we cant see your links from Google drive. But here is the abstract at least:
Abstract
The peculiar short-faced Californian bear, known as Arctotherium simum, was described by Cope in 1879 from a single specimen, consisting of a skull minus the lower jaw, found by J. A. Richardson in 1878 in Potter Creek Cave on the McCloud River in northern California. Since the description of A. simum, a nearly perfect skull with lower jaw and a large quantity of additional material, representing nearly all parts of the skeleton and dentition of this species, has been obtained from the deposits of Potter Creek Cave as a result of further work carried on for the University of California by E. L. Furlong and by W. J. Sinclair in 1902 and 1903.
authors.library.caltech.edu/99157/
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Post by tyrannosaurs on Aug 3, 2021 8:27:44 GMT -5
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Post by tyrannosaurs on Aug 3, 2021 8:43:51 GMT -5
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Post by Gorilla king on Aug 3, 2021 8:58:08 GMT -5
The Tremarctinae or short-faced bears is a subfamily of Ursidae that contains one living representative, the spectacled bear (Tremarctos ornatus) of South America, and several extinct species from four genera: the Florida spectacled bear (Tremarctos floridanus), the North American short-faced bears of genera Plionarctos (P. edensis and P. harroldorum) and Arctodus (A. pristinus and A. simus), and the South American giant short-faced bears of Arctotherium (including A. angustidens, A. vetustum, A. bonariense, A. wingei, and A. tarijense).[1] The group is thought to have originated in eastern North America, and then invaded South America as part of the Great American Interchange.[2]
Systematics
Traditionally, analyses of the phylogenetic inner relationships of tremarctines had Plionarctos and Tremarctos as basal groups with respect to a short-faced bear clade of Arctodus and Arctotherium.[3][4] A study of the affinities of bears belonging to Arctotherium indicates that they were more closely related to the spectacled bear than to Arctodus, implying convergent evolution of large size in the two lineages.[5]
en.m.wikipedia.org/wiki/Tremarctinae
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Post by Gorilla king on Aug 3, 2021 9:30:48 GMT -5
ARCTODUS PRISTINUS-PARTIAL RIGHT MANDIBULAR RAMUS
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Post by Gorilla king on Aug 3, 2021 9:35:45 GMT -5
FLORIDA VERTEBRATE FOSSILS
Arctodus pristinus
Quick Facts
Common Name: Lesser short-faced bear
Largest land canivore in Florida during the early Pleistocene.
Among living bears, most closely related to the spectacled bear of South America.
Age Range
Early to middle Pleistocene Epoch; Blancan and Irvingtonian land mammal agesAbout 2.5 to 0.5 million years agoScientific Name and Classification
Arctodus pristinus Leidy, 1854
Source of Species Name: Leidy (1854) did not provide a reason for the species name, but pristinus in Latin means ‘primitive‘ or ‘early’. This name may have been given because Arctodus pristinus was the first Arctodus Leidy identified.
Classification: Mammalia, Eutheria, Laurasiatheria, Caniformia, Carnivora, Arctoidea, Ursoidea, Ursidae, Tremarctinae
Alternate Scientific Names: Ursus haplodon; Arctodus haplodon
Figure 1. Map of Florida, with highlights indicating counties where fossils of this species have been found.
Overall Geographic Range
Eastern and possibly central United States, including occurrences in Florida, coastal South Carolina, Maryland, southeastern Pennsylvania, possibly Kansas (Kurtén, 1967; Emslie, 1995), and Central Mexico (Dalquest and Mooser, 1980). Ashley River, near Charleston, South Carolina, is the type locality.
Florida Fossil Occurrences
Florida fossil sites with Arctodus pristinus:
Alachua County—Haile 16ABrevard County—Sebastian Canal 2Charlotte County—Port Charlotte area (specific location unknown)Citrus County—Crystal River Power Plant; Inglis 1A; Inglis 1BColumbia County—Santa Fe River 1Hillsborough County—Apollo Beach; Leisey Shell Pit 1; Leisey Shell Pit 1A; Leisey Shell Pit 3Levy County—McLeod Limerock MineOkeechobee County—Kissimmee 6Sarasota County—Bass Point Waterway; Rigby Shell Pit; Venice BeachSumter County—Coleman 2ADiscussion
Arctodus pristinus is a large tremarctine bear. More fossils of this species are known from Florida (about 150) than anywhere else. Compared to the gigantic Arctodus simus, the premolars and first molars of Arctodus pristinus are relatively smaller and more widely spaced (Figs 2-5; Schubert et al., 2010). Both species show pronounced intraspecific variation, much of it related to sexual dimorphism, with smaller, more lightly built females and larger, massive males. Males of the smaller species A. pristinus overlap in size with females of A. simus.
There is even greater overlap in size between A. pristinus and the late Pleistocene species Tremarctos floridanus. The molars of A. pristinus are, on average, broader and taller than those of Tremarctos floridanus, but these differences are quickly obscured by wear. Most published comparisons are between the two species of Arctodus, or between A. simus and T. floridanus, and not between the two more similar-sized A. pristinus and T. floridanus. Samples are now available to make such comparisons worthwhile. Although not completely satisfactory, in practice large tremarctine fossils from the early to early middle Pleistocene of Florida can be identified as A. pristinus, while those from the late Pleistocene are considered T. floridanus. Specimens of ambiguous age, unless they include molar teeth that are relatively complete and unworn or only slightly worn, will be very difficult to identify precisely.
The genus Arctodus is generally regarded as being more carnivorous than either Tremarctos or the black bear Ursus americanus. Its large size would allow it to take carcasses away from most other carnivores, especially solitary felids. The bite marks found on many bones of sloths and young proboscideans at Leisey Shell Pit matched the size of the canine teeth of Arctodus pristinus (Pratt and Hulbert, 1995). It is not known if these bite marks are the result of active predation or scavenging.
www.floridamuseum.ufl.edu/florida-vertebrate-fossils/species/arctodus-pristinus/
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Post by tyrannosaurs on Aug 3, 2021 9:36:51 GMT -5
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Post by tyrannosaurs on Aug 3, 2021 9:37:22 GMT -5
Nice King Kodiak, that's the Lesser Short Faced bear of I am correct?
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Post by Gorilla king on Aug 3, 2021 9:43:43 GMT -5
Nice King Kodiak, that's the Lesser Short Faced bear of I am correct? You are correct.
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Post by tyrannosaurs on Aug 3, 2021 10:05:36 GMT -5
Nice site king Kodiak. You got any other sizes?
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Post by Gorilla king on Aug 3, 2021 10:14:40 GMT -5
The southernmost bear: Pararctotherium (Carnivora, Ursidae, Tremarctinae) in the latest Pleistocene of Southern Patagonia, Chile.
Abstract
A second upper incisor belonging to the tremarctine bear Pararc-totherium was recovered from latest Pleistocene deposits in Cueva de los Chingues, Magallanes, Chile (San Roman et al., 2000; Fig. 1). This is the southernmost record of an ursid in the world and one of the youngest records of Pararctotherium. The paleoenvironment of south-ern Patagonia in the latest Pleistocene (ca. 11,000 yBP) was a cold grassland. The Ursidae originated during the late Eocene in the Holarctic region and throughout its history has primarily been restricted to the Northern Hemisphere. Ursids twice dispersed into Africa (Hunt, 1996): the Hem-icyoninae in the early Miocene and Agriotherium in the late Miocene, with the latter reaching the southern tip of Africa (ca. 33Њ 43Ј S). The Tremarctinae is comprised of five genera: Plionarctos, consid-ered Pararctotherium to be a subgenus of Arctotherium. We regard both Arctotherium and Pararctotherium as valid, distinct genera based on the systematic and phylogenetic revision of South American fossil bears by LHS (e.g., Soibelzon, 2000, 2002; Soibelzon et al., 2000). Tremarctines dispersed into South America from North America at least twice. The oldest records of Arctotherium are early Pleistocene (Ensenadan age; Kraglievich and Ameghino, 1940; Berman, 1994; Soi-belzon and Bond, 1998; Soibelzon et al., 2001; Soibelzon, 2002). Tre-marctos, which lacks a fossil record in South America, probably crossed the Panamanian Isthmus in the latest Pleistocene or Holocene (Soibel-zon, 2002). South American fossil bears are primarily recovered from the Pampean Region (ca. 33Њ S), with isolated finds in Brazil, Bolivia, Chile, Venezuela, and Uruguay. Arctotherium latidens is the lone En-senadan tremarctine in South America. Following its extinction, tre-marctines were represented by several species of Pararctotherium dur-ing the middle to late Pleistocene (Bonaerian and Lujanian ages; Cione and Tonni, 1999). It was distributed widely across southern South America (Bolivia, Brazil, Argentina, Uruguay, and Chile) and persisted until the end of the Lujanian (Soibelzon and Bond, 1998; Soibelzon, 2002).
www.researchgate.net/publication/263381230_The_southernmost_bear_Pararctotherium_Carnivora_Ursidae_Tremarctinae_in_the_latest_Pleistocene_of_Southern_Patagonia_Chile
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Post by Gorilla king on Aug 3, 2021 10:27:34 GMT -5
TREMARCTINAE EVOLUTION
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Post by Gorilla king on Aug 3, 2021 10:30:43 GMT -5
The fossil record of South American short-faced bears (Ursidae, Tremarctinae)
Abstract and Figures
The present study includes a review of the geographic and stratigraphic distribution of short-faced bears (Ursidae, Tremarctinae) in South America. In addition, the authors discuss biogeographic hypotheses regarding the origin of South American tremarctines. The Tremarctinae subfamily is distributed exclusively in America, from Alaska to southern Patagonia. Its biochron comprises the temporal lapse between Late Miocene and recent times; the first record of Tremarctinae in North America corresponds to the Hemphillian and the last to the Rancholabrean. In South America, the first record corresponds to the Ensenadan. In the present day, it corresponds to the only living tremarctine, the ‘Andean Bear,’ but short-faced bears became extinct during the early Holocene. The extinction of short-faced bears in North and South America appears to have been approximately synchronous. Finally, the fossil record in South America indicates species turnover between the Ensenadan and Bonaerian, during which time the giant species Arctotherium angustidens was replaced by Arctotherium tarijense, Arctotherium bonaeriense, and Arctotherium vetustum (and probably Arctotherium wingei).
www.researchgate.net/publication/223390695_The_fossil_record_of_South_American_short-faced_bears_Ursidae_Tremarctinae
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Post by tyrannosaurs on Aug 3, 2021 10:47:16 GMT -5
These all are awesome king Kodiak! Keep it up!
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Post by Gorilla king on Dec 26, 2021 10:41:11 GMT -5
PLIONARCTOS
Plionarctos is an extinct genus of bear endemic to North America from the Miocene to the Pliocene,[2] ~10.3—3.3 Mya, existing for about 7 million years.
Indarctos (10.7—9.2 Mya) 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 million — 11,000 years ago) and shared its habitat. Plionarctos is the oldest known genus within the subfamily of the short-faced bears (Tremarctinae), and is believed to be ancestral to the clade.
en.m.wikipedia.org/wiki/Plionarctos
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Post by Gorilla king on Dec 26, 2021 10:46:06 GMT -5
Plionarctos, a Tremarctine Bear (Ursidae: Carnivora) from Western North America
Abstract
The Pliocene Ringold Formation of eastern Washington has yielded important new materials of tremarctine bears of the anagenetic Plionarctos lineage. The genus is reviewed in light of this new material and observations made on other described specimens. One of these was previously described from the medial Hemphillian Rattlesnake Formation of Oregon and is recognized as a tremarctine bear, thus extending the earliest record of the group into the early part of the late Miocene. The late Hemphillian P. edensis, the genotypic species, is rediagnosed, although no new material is added to its hypodym. A new species from the early Blancan White Bluffs sites, P. harroldorum, appears to have been derived from P. edensis. Referred Plionarctos sp. from the medial Blancan Taunton Locality has some dental features that are more derived and approach those of the Pleistocene Tremarctos floridanus. Plionarctos forms a paraphyletic stem-group for the Tremarctinae. Species of this genus can be traced successively into the Pliocene where they form the stock from which the Pleistocene and Recent species of Tremarctos, Arctodus, and Pararctotherium arose.
www.jstor.org/stable/20061955
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Post by Gorilla king on Dec 27, 2021 12:21:30 GMT -5
A Fossil Bear from Northeastern Brazil, with a Phylogenetic Analysis of the South American Extinct Tremarctinae (Ursidae)
Abstract
The skull with mandible of a fossil tremarctine bear from Ubajara county, northeastern Brazil, is described and compared to other specimens belonging to the nominal species, Arctodus (Pararctotherium) brasiliensis. It differs from the other almost complete skull, from Minas Gerais State, in having a shorter, more slender rostrum, larger braincase, and smaller teeth. We also propose a phylogenetic hypothesis and correspondent classification for the genera of Tremarctinae, using cladistic methodology. Arctodus and Arctotherium are recognized as separate genera, with the latter including two subgenera, Arctotherium and Pararctotherium. The Ubajara bear is tentatively identified as Arctotherium (P.) brasiliense (comb. nov.).
www.jstor.org/stable/4523593
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Post by brobear on Dec 27, 2021 13:47:54 GMT -5
en.wikipedia.org/wiki/Arctotherium Arctotherium ("bear beast") is an extinct genus of the Pleistocene South American short-faced bears within Ursidae. Their ancestors migrated from North America to South America during the Great American Interchange, following the formation of the Isthmus of Panama during the late Pliocene. The oldest dated confirmed remains are those of A. angustidens from Buenos Aires, Argentina, dating to the Ensenadan epoch, 1.76 to 0.98 Ma old, within the Early to Middle Pleistocene, with a tooth possibly belonging to Arctotherium dating about 2.588 Mya. *The biggest of them is also the oldest species of Arctotherium. So, what bear species is the direct ancestor of Arctotherium angustidens?
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Post by Gorilla king on Dec 27, 2021 14:20:17 GMT -5
Trust me, for the last 5 hours i have been going absolutely crazy re-reading this thread, the Angustidens thread, and the bear evolution thread. I also read the whole study at reply #13. To be honest nowhere is mentioned who is the direct ancestor of Angustidens, maybe its not even known. I dont think its Plionarctos as it never reached South America, no fossil records there.From reply #13:
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