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Post by OldGreenGrolar on Jul 26, 2020 6:29:58 GMT -5
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Post by King Kodiak on Jul 26, 2020 10:18:37 GMT -5
/\ Look at the massive size difference. Imagine standing beside that bear. Looks to me like that little jaguar does not want to defend its kill, ha ha ha.
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Post by OldGreenGrolar on Sept 21, 2020 4:31:26 GMT -5
/\ Look at the massive size difference. Imagine standing beside that bear. Looks to me like that little jaguar does not want to defend its kill, ha ha ha.That is because the Arctotherium is much larger and heavier. No animal in the wild wants to risk death with a larger one.
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Post by King Kodiak on Oct 29, 2020 1:44:17 GMT -5
/\ Could you translate that to English please? The sizes and weights should not be taken as absolute, they are estimates of maximum averages. In some cases, such as Arctotherium angustidens, a probable maximum of about 1800 kg is estimated and in Simbakubwa kutokaafrika about 1500 kg. In the case of Andrewsarchus mongoliensis, only the skull is counted, so estimates of its total body size and weight are quite varied.
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Post by King Kodiak on Oct 29, 2020 8:54:00 GMT -5
Reply #107: good find brobear. Here is some general info on the Macrauchenia:
Macrauchenia had a somewhat camel-like body, with sturdy legs, a long neck and a relatively small head. Its feet, however, more closely resembled those of a modern rhinoceros, with one central toe and two side toes on each foot. It was a large animal, with a body length of around 3 metres (9.8 ft) and a weight up to 1,042.8 kg (2,299 lb), about the size of a black rhinoceros.[13][14]
en.m.wikipedia.org/wiki/Macrauchenia
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Post by King Kodiak on Dec 19, 2020 20:23:50 GMT -5
Fossils of Extinct Bear Species Found in Mexico
Four complete skulls and jaws of a Pleistocene bear species called Arctotherium, that disappeared 11,300 years ago, were found by aquatic archaeologists in a submerged cave on the Yucatan peninsula in Mexico.
The 25-30 cm long skulls discovered at 42 meters underwater, belong to two adult bears - one of each sex - and two bears that had not reached full maturity.
The discovery was made by Guillermo de Anda Alanis and his team from the Yucatan Autonomous University, while they were diving in a cavern, as part of the project authorized by the National Institute of Anthropology and History (INAH) “El Culto al Cenote en el Centro de Yucatan” (Cult to Cenote in Central Yucatan).
Guillermo de Anda Alanis said that the fossils were found between the towns of Sotuta and Homun, in Yucatan, spread on a 120 meters diameter surface.
The four skulls seem to belong to a family of bears of the same species, because the 2 adult skulls belonged to a male and a female, and the 2 other did not reach full development.
The preliminary investigations of the fossils were made in situ, but further research is necessary, artdaily reports.
What is known until now, is that these are the only specimens of their type found until now in this region of the country, and they add to the few Prehistorical animals discovered in this type of water bodies, which were dry caves before glaciations.
These fossils challenge the biogeography of bears in the Americas, since Arctotherium was previously known to only have lived in South America.
De Anda said that at first the remains were thought to have belonged to jaguars, but archaeozoologist Christopher Gotz from Yucatan Autonomous University carried out the morphological identification of the skulls, and confirmed they belonged to bears, because of their strong, flat and wide molars.
Gotz said that species related to Arctotherium in America are the extinct North American short-faced bears(Arctodus simus and pristinus), the Florida short-faced (Tremarctos floridanus), the Mexico short-faced (Tremarctos mexicanus) and the last survivor that lives in South America, the Andean short-faced bear (tremarctos ornatus).
Besides the bear fossils, the archaeologists also found skeletal remains of five humans, and further dating of these skeletons should establish if the two discoveries are connected.
De Anda said that “this research is only beginning, and it will most likely provide important data for the knowledge of the first species that inhabited the region, as well as of the historical periods to which human remains yet to be analyzed belong.
“We are looking forward to confirm after analyses that the remains correspond to that genus, since it would enlarge the knowledge regarding this animal’s natural history and their relation with their closer relatives.”
He announced the details of the discovery at the International Congress American Cultures and their Environment: Perspectives from Zoo Archaeology, Paleo Botanic and Ethno Biology, organized by the Yucatan Autonomous University in Merida, Yucatan.
news.softpedia.com/news/Fossils-of-Extinct-Bear-Found-in-Mexico-165122.shtml
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Post by brobear on Dec 19, 2020 20:34:34 GMT -5
Reply #111 super interesting King Kodiak. Arctotherium in Mexico plus ( new-to-me ) Tremarctos mexicanus.
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Post by King Kodiak on Dec 19, 2020 20:44:46 GMT -5
Reply #111 super interesting King Kodiak. Arctotherium in Mexico plus ( new-to-me ) Tremarctos mexicanus. Yeah, to be more precise, the species in Yucatan, Mexico is Arctotherium wingei.
ABSTRACT
The Great American Biotic Interchange is considered to be a punctuated process, primarily occurring during four major pulses that began approximately 2.5 Ma. Central America and southeastern Mexico have a poor fossil record of this dynamic faunal history due to tropical climates. Exploration of submerged caves in the Yucatán, particularly the natural trap Hoyo Negro, is exposing a rich and remarkably well-preserved late Pleistocene fauna. Radiometric dates on megafauna range from approximately 38 400–12 850 cal BP, and extinct species include the ursid Arctotherium wingei and canid Protocyon troglodytes. Both genera were previously thought to be indigenous to and confined to South America and appear to represent an instance of large placental mammals, descended from North American progenitors, migrating back north across the Panama Isthmus. This discovery expands the distribution of these carnivorans greater than 2000 km outside South America. Their presence along with a diverse sloth assemblage suggests a more complex history of these organisms in Middle America. We suggest that landscape and ecological changes caused by latest Pleistocene glaciation supported an interchange pulse that included A. wingei, P. troglodytes and Homo sapiens.
www.ncbi.nlm.nih.gov/pmc/articles/PMC6548739/
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Post by brobear on Oct 17, 2021 2:23:49 GMT -5
Paleoartists The largest terrestrial carnivore seen since non-avian dinosaurs disappeared at the end of the Mesozoic era, is a gigantic South American short-faced bear, Arctotherium angustidens, with a mass of up to 1700 kilograms ( 3,747.86 pounds ), this is calculated by allometric equations considering the width of his humerus. It was the terror of the Argentine pampa during the pleistocene. Here we see a large male attacking a young adult Notiomastodon platensis.
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Post by brobear on Nov 20, 2021 6:36:30 GMT -5
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Post by brobear on Dec 28, 2021 5:15:51 GMT -5
www.ncbi.nlm.nih.gov/pmc/articles/PMC6548739/ Disagreements have occurred over the evolutionary relationship of Arctotherium, Tremarctos and Arctodus, with earlier morphological interpretations placing Arctotherium and Arctodus as sister taxa. Recent genetic analyses indicate Arctotherium is more closely related to Tremarctos, and therefore Arctotherium and Arctodus share morphologies that may relate to their large size and/or dietary behaviour. Based on our understanding of the group, Arctotherium arose from Tremarctos, or a common ancestor that excluded Arctodus. *Probably, either a particular population of Tremarctos floridanus or else some as yet undiscovered Tremarctine bear species had ventured into South America from the North and, given time, evolved into the first Arctotherium.
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Post by brobear on Dec 31, 2021 9:17:42 GMT -5
The Pleistocene Epoch First image is a wonderful masterpiece by the very well known artist Júlia d'Oliveira. Long ago on the plains of Bolivia, during the Pleistocene Epoch. A pair of omnivore short-faced bears called Arctotherium wingei have come to feed on some fallen fruit, one investigates the body of a deceased Nothrotherium maquinense. Arctotherium wingei is one of five described Arctotherium species endemic to South America, Arctotherium angustidens for example is known for being the earliest, largest, and most carnivorous member of the genus. Arctotherium was named by Hermann Burmeister in 1879, although the type species A. bonariense was named by Gervais in 1852. The other four are A. angustidens (Gervais and Florentino Ameghino, 1880), A. tarijense (Florentino Ameghino, 1902), A. vetustum (Florentino Ameghino, 1885) and A. wingei (Florentino Ameghino, 1902). Arctotherium means, "bear beast" and is classified as Chordata, Mammalia, Carnivora, Ursidae and Tremarctinae. Fossils of Arctotherium have been found in many locations throughout South America; Argentina (Luján Formation), Bolivia (Taríja and Ñuapua Formations), Brazil (Jandaíra Formation), Chile (Cueva de los Chingues), Yucatán, Mexico (Sistema Sac Actun) and Taima-Taima, Muaco and Cueva del Guácharo, Venezuela. It lived during the Early Pleistocene to Early Holocene Epochs (Ensenadan to Lujanian Ages 1.2 MYA - 11,000 BCE). The species A. angustidens from Buenos Aires, is considered the largest bear ever found and contender for the largest carnivorous land mammal known. They weighed between 983 to 2,042 kg (2,167 - 4,502 lbs), though most consider the upper limit to be improbable with a more accepting estimate of 1,588 to 1,749 kg (3,501 - 3,856 lbs) to be more likely. An estimated standing height for Arctotherium angustidens is between 3.4 - 4.3 meters (11 - 14 feet). Now since Arctotherium is a short-faced bear, you could be forgiven thinking it's related to the short-faced bear Arctodus of North America. Arctotherium is genetically closer to the spectacled bear (Tremarctos ornatus), this implies that Arctodus and Arctotherium evolved large size in a convergent manner, perhaps to facilitate dominating other carnivores in the competition for the biggest carcasses. Arctotherium's large size could also have been a reaction to increased competition from other, later-arriving or evolving carnivores, such as jaguars, Protocyon or Smilodon, following the early dispersal of short-faced bears to South America. Nothrotherium is a member of South Americas famous ground sloths. The genus was named by Richard Lydekker in 1889 and is represented by two species: Nothrotherium maquinense (Lund, 1839) and Nothrotherium escrivanense (Reinhardt, 1878). Nothrotherium means "Lazy beast", derived from the Greek word nothros meaning "lazy" or "slothful" and therion, meaning "beast", the type species N. maquinense is named after the Maquiné Grotto in Brazil, where it was found. Classified as Chordata, Mammalia, Pilosa, Nothrotheriidae and Nothrotheriinae. Fossils of Nothrotherium have been mainly found in Brazil, other remains have been unearthed in Bolivia and La Guajira, Colombia (Ware Formation). It lived during the Middle to Late Pleistocene Epoch (Calabrian - Lujanian Ages 1.8 MYA - 12,200 BCE). Nothrotherium was a small to medium-sized ground sloth, reaching about 1.5 meters (4.9 feet) in length and 463 kg (1,020 lbs) in weight. Being a nothrotheriid they were small compared to some of their megatheriid relatives, their claws provided an effective defense against predators, like those of larger anteaters today. There is presence of Nothrotherium torresi in sediments related to humid conditions, supporting the idea that members of the Nothrotheriinae had great ecological tolerance and was capable of inhabiting climates ranging from cold and arid to warm and humid. Second image shows a skull of Arctotherium tarijense. (A–C) MACN 971. A, Ventral; B, lateral; C, occipital views of the skull; (D–F) MHJ 544. D, Ventral; E, lateral; F, occipital views of the braincase; (G–I) MLP 10-5. G, Ventral; H, lateral; I, occipital views of the braincase. BO, pars basilaris os occipitale; BT, bulla tympanica; CET, contact exoccipital-bulla tympanica; CO, condylus occipitalis; ET, Eustachian tube; FH, foramen n. hypoglossis; FJ, foramen jugulare; FL, foramen lacerum; FM, foramen magnum; FPG, foramen postglenoideum; FS, foramen stylomastoideum; MAE, meatus acusticus externus; PM, processus mastoideus; PPG, processus postglenoideus; PPO, processus paraoccipitalis; OC, os occipitale. Scale bar at 5 centimeters. Third image is a Nothrotherium skeleton displayed at the Peabody Museum of Natural History at Yale University, in New Haven, Connecticut, USA.
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Post by brobear on Dec 31, 2021 9:18:11 GMT -5
First image is a wonderful masterpiece by the very well known artist Júlia d'Oliveira.
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Post by Deleted on Aug 26, 2022 22:24:11 GMT -5
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Post by brobear on Nov 3, 2022 8:23:30 GMT -5
The 5 Known Species of Arctotherium were Prehistoric Carnivorous or Omnivorous they lived around 2.2 Million - 12 000 Years Ago , they lived Forward too South America during the early Pleistocene too early Holocene ! the Arctotherium Angustidens is the Largest Species of Arctotherium , and was even Largest Mammal Carnivorous , and it was the Largest and Strongest Bear , that ever lived in it's history , and Heaviest powerful Built then that Giant Short-Faced Dog Epicyon Haydeni this species Meaning Name is "Giant Top Bear" , lived at Middle Pleistocene too Early Holocene around 1.4 Million - 12K Years Ago , weighting about 2,100 and 4,500 Pounds and heighting about 11–14 Feet , these fossils are found in Whole South America ! www.deviantart.com/demitriusthewolf999/art/Arctotherium-Height-Chart-881999953the Arctotherium Bonariense is the medium species between the large and small species of Arctotheriums that could be similar to a Bison or a Yak , this medium Arctotherium lived in whole Brazil about 1.4 Million - 12K Years ago , these Arctotherium can steal preys like Smilodons , Protocyons , Maned Wolves , Terror Birds and even too Jaguars , the Arctotherium Bonariense are omnivorous ! the Arctotherium Tarjiense is one of the Medium Species of Arctotherium Family , they were smilar too a Cattle , they were about 1600 - 3500 Pounds , and were heighting around 7-10 Feet ! Arctotherium Vetustum is the Small species of Arctotherium Family , they were 200 - 480 Pounds , and heighting was 5.5-8.6 Feet ! and Finally one more Species of Arctotherium was this A. Wingei is one of small Species of Arctotherium , they were 5 known Species they have lived !
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Post by brobear on Nov 3, 2022 8:24:03 GMT -5
Arctotherium Height Chart Published: Jun 7, 2021 by DemitriustheWolf999
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Post by OldGreenGrolar on Nov 19, 2022 4:41:16 GMT -5
This is the only bear that encounters the smilodon populator.
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Post by brobear on Nov 26, 2022 2:15:07 GMT -5
The giant along-side his living relative:
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