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Post by brobear on Nov 16, 2019 9:17:18 GMT -5
Grrraaahhh: Good news everyone. Collection of materials on the Americas GSFB HEAVYWEIGHTS have met with good success. Many of us have been following with strong interest the latest material covering Arctotherium angustidens. The new data on the giant South American specimen inspired me to double check and dig around for material on its comparable sized North American cousins; the Giant Short Faced Bear (A. simus). By my count, there are a handful of fossil specimens that are comparable in scope, however, the heavier build advantage goes to the South American bear. They include a northern Californian specimen with a record size ulna measurement of 591 mm; the Lake Bonville, Utah specimen with a record size femur measurement of 723 mm; a Kansas specimen with a record size humerus measuring 646 mm; a Cass County (Nebraska) specimen with a humerus measurement of 633 mm, and another large Nebraska specimen from Hay Springs. Although less revealing, a future review (to better cross reference) of skull and dental data is warranted and planned. How would a completed Gold Run Creek, Yukon Territory (record size skull find) specimen compare to some of its larger cousins? Back to our original theme and to wrap up things, unpublished photos (i.e., our northern California specimen), plus illustrations (e.g., the Cass County, NE humerus) and material data have been collected and are being organized. domainofthebears.proboards.com/thread/80/arctotherium?page=4&scrollTo=21360
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Post by brobear on Nov 16, 2019 9:20:00 GMT -5
Sorry for the delay (busy schedule, material collection & organizing, etc) but I wanted to get things rolling here. First some updates, I was hoping and I am still trying to obtain fossil photos for two large Arctodus simus specimens one of them from Kansas and the other from Hay Springs, Nebraska. My efforts have led me to conclude that there has been no published photo release of these two specimens. Now for the good news - we will have a forum milestone of sorts. I did find success in obtaining photos for the Irvingtonian (Alameda, CA) specimen. FYI, there has been no published release of photos for the Irvingtonian specimen. Photos for the Cass County humerus and Lake Bonneville femur have been acquired (the Utah specimen can be found online if you look hard enough).
What I am providing here is a humerus and femoral fossil comparison table for the largest A.simus & A.angustidens’ specimens.
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Post by brobear on Nov 16, 2019 9:21:28 GMT -5
As the data reveals, although there are North American A.simus specimens that produce longer humerus values, a review of the mid shaft width values tell us that A.angustidens is the heavier built bear. Comparable femoral data suggest a similar conclusion.
The closest North American specimen to approach A.angustidens relative to robusticity is the specimen from Kansas. In the North American theater, the Kansas River specimen produced a higher mid shaft width femoral values than both the Lake Bonneville and Hay Springs bears. Moreover, the Kansas specimen produces a longer humerus than the Cass County, Nebraska GSFB. Update: With the exception of the Hay Springs sample, all other specimen material have been obtained.
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Post by brobear on Nov 16, 2019 9:24:06 GMT -5
tremarctinae: The data you have collected are wonderful, thanks!
I have a few questions please:
1. there are 6 large specimens of arctodus simus, the 6 specimens you provided are KUVP C-2427, Cass county Nebraska, KUVP 131586, UVP 015/1, Hay Springs and UC 44687, right?
KUVP C-2427 seems to have the longest humerus but UVP 015 seems to have the longest femoral. So these bones are different, so we can't claim which is the biggest specimen of arctodus simus?
2. i have been searching informations for a lot of weeks to try reconstructing the real height of UVP/015 when it is standing up but i failed. So please, you know very well bears, can you give me an approximation of the height of UVP 015 at the shoulders and when it is standing up?
3. I have compared 2 skeletons between ursus arctos and short faced bear. They have the same number of vertebrae: why giant brown bears like goliath (12 feets tall right?) or super giant brown bears from russia in the early 20th century (with skins around 350 cm from the nose to the tail involving a height perhaps more than 3,7 meters) are taller than arctotherium angustidens?
Thanks a lot for your comments.
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Post by brobear on Nov 16, 2019 9:25:35 GMT -5
The earlier humerus data make up the top four (three bears total) GSFB largest humerus fossils. Two bears are from North America, the other & heaviest bear is from Argentina. KUVP 131586: Regrettably, the distal end for this left femur is missing so the incomplete data was ignored. UC 44686 (the longest GSFB ulna fossil): Ulna measurements A: 591 B: - C: 65 D: 47 E: 35.2 A. Greatest Length. B. Proximal diameter from tip of coronoid progress to Margo dorsalis. C. Smallest diameter from bottom of semi circular notch to Margo dorsalis.. D. Inner diameter of semi circular notch. E. Least transverse diameter of shaft, above capitulum. UC 44687 (2nd total length GSFB femur) Femur Measurements: A. 678 B. a165 C. 77 D. 62 E1. 134 A. Greatest Length. B. Greatest proximal width. C.Caput diameter. D. Least transverse width of shaft. E1. Greatest distal width over epicondyles. Source: Kurten (1967). Both CA specimen unpublished photos have been obtained & plans are to publish them later similar to the earlier humerus figure material. Ideally, I was hoping to obtain photos for the Hay Springs bear for a comprehensive publication but travel issues & scheduling conflict have complicated matters. Femoral measurements (1st in total length GSFB femur fossil): UVP 015 Lake Bonville, Utah Specimen & Material: UVP 015/1 Greatest length: 723 Greatest proximal width: 191 Caput diameter: - Least transverse width of shaft: 64 Greatest distal width over condyles: 152 shaggygod.proboards.com/index.cgi?board=americaspleistocene&action=display&thread=329&page=2See reply # 22. Keep in mind, different fossil models produce different weight estimates. There are some data I want to review. I will try to follow up more shortly.
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Post by brobear on Nov 16, 2019 9:44:51 GMT -5
tremarctinae: Unfortunately, we can't read the paper, only the first page is accessible...
Well, i noticed that the short faced bear skeleton on boneclones (http://www.boneclones.com/images/sc-114-a-lg.jpg) is based on a 25 inches femur (63,5cm) and a 22 inches humerus(55,88cm) and this reconstitued specimen is 12 feet tall (3,65 meters). So can we conclude that UVP 015 which has a femoral of 72cm in length is taller than 3,65 meters?
You have probably noticed that arctotherium angustidens is supposed 3,4 meters standing up with a humerus of 62 cm in length...
I am getting desperate nobody can't give me some explanations with this measures.
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Post by brobear on Nov 16, 2019 9:45:45 GMT -5
Grrraaahhh: The Soibelzon and Blaine 2011 Arctotherium angustidens article is subscription access only. If you enjoy university access a lot of your questions can be answered as they are addressed in numerous articles almost all of them subscription based.
RE: boneclones estimate/data - I would not place much stock in it, here, professional paleontologist data trumps all. Remember, they are profit driven and a little hyperbole will help their bottom line (don't believe everything you read). FYI, conventional professional accounts for bipedal height for mature/large GSFB is 3.4 meters.
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Post by brobear on Nov 16, 2019 9:49:51 GMT -5
The earlier humerus data make up the top four (three bears total) GSFB largest humerus fossils. Two bears are from North America, the other & heaviest bear is from Argentina. KUVP 131586: Regrettably, the distal end for this left femur is missing so the incomplete data was ignored. UC 44686 (the longest GSFB ulna fossil): Ulna measurements A: 591 B: - C: 65 D: 47 E: 35.2 A. Greatest Length. B. Proximal diameter from tip of coronoid progress to Margo dorsalis. C. Smallest diameter from bottom of semi circular notch to Margo dorsalis.. D. Inner diameter of semi circular notch. E. Least transverse diameter of shaft, above capitulum. UC 44687 (2nd total length GSFB femur) Femur Measurements: A. 678 B. a165 C. 77 D. 62 E1. 134 A. Greatest Length. B. Greatest proximal width. C.Caput diameter. D. Least transverse width of shaft. E1. Greatest distal width over epicondyles. Source: Kurten (1967). Both CA specimen unpublished photos have been obtained & plans are to publish them later similar to the earlier humerus figure material. Ideally, I was hoping to obtain photos for the Hay Springs bear for a comprehensive publication but travel issues & scheduling conflict have complicated matters. Femoral measurements (1st in total length GSFB femur fossil): UVP 015 Lake Bonville, Utah Specimen & Material: UVP 015/1 Greatest length: 723 Greatest proximal width: 191 Caput diameter: - Least transverse width of shaft: 64 Greatest distal width over condyles: 152 shaggygod.proboards.com/index.cgi?board=americaspleistocene&action=display&thread=329&page=2See reply # 22. Keep in mind, different fossil models produce different weight estimates. There are some data I want to review. I will try to follow up more shortly.
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Post by brobear on Nov 16, 2019 9:51:10 GMT -5
Body Mass Estimation
There have been few attempts to estimate the size of the ‘short-faced’ bear. Where estimates were made, often the sample size was small.
Limb bones are responsible for supporting the animal’s weight during locomotion (Anyonge, 1993; Christiansen and Harris, 2005), thus providing the best mass estimates for extinct species. Kurt´en (1967) used the reconstructed body length and the cross-sectional area of a femoral diaphysis of a large specimen from Hay Springs for calculating its mass as between 470 and 630 kg.
Employing Kurt'en's method, Nelson and Madsen (1983) obtained an estimate of 620–660 kg for the specimen UVP 015 from Salt Lake County (Northern Utah), based on the diaphyseal area of the femur.
Christiansen (1999b) used several measurements taken in the proximal limb bones to estimate the mean mass of three specimens of A. simus as ca. 770 kg.
Figueirido et al. (2010) measured the maximum length and least width of the diaphyseal shaft of each major limb bone in a data set of 58 specimens of the eight species of extant ursids. Log-transformed data were used for calculating least squares bivariate regression functions of body mass on each measurement. For each bear species, we used published estimates of average mass (Van Valkenburgh, 1990; Christiansen, 1999b, 2002; Egi, 2001; Anderson, 2004). The accuracy of the bivariate regression functions was evaluated from their percent prediction errors (%PE) and the percent standard error of the estimates (%SEE) following Smith (1981, 1984). Approximately one third of specimen body mass estimates approached one tonne - the author further speculates that bears of this size were more common than previously suspected.
Soibelzon and Schubert (2011) obtained body mass of South American short-faced bears following the estimates by Soibelzon and Tartarini (2009) employing the allometric equations published by other authors (e.g., Van Valkenburgh,1990; Anyonge, 1993; Viranta, 1994; Christiansen, 1999; Egi, 2001). The study by Soibelzon and Tartarini (2009) compared more than sixty equations based on teeth, skull and postcranial measurements, and found the most reliable predictor of body size for large specimens was six measurements of the humerus (proposed by Anyonge, 1993; Egi, 2001; Christiansen, 1999) and one on the radius (formulated by Viranta, 1994) (for more details see Soibelzon and Tartarini, 2009). Thus, the size of the individual described here is estimated based on the preserved humerus and radius using these seven equations. The result, the Argentine specimen had an estimated body mass ranging from 983 to 2,042 kg depending on the equations considered while the mean and median body mass estimates (considering all equations) were 1,588 and 1,749 kg respectively.
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Post by brobear on Nov 16, 2019 9:54:30 GMT -5
1588 kilograms is equal to 3,500.94 pounds (avoirdupois) 1749 kilograms is equal to 3,855.88 pounds (avoirdupois) Upper Max from 3500 to 3900 pounds.
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Post by King Kodiak on Nov 16, 2019 9:58:16 GMT -5
1588 kilograms is equal to 3,500.94 pounds (avoirdupois) 1749 kilograms is equal to 3,855.88 pounds (avoirdupois) Upper Max from 3500 to 3900 pounds. This is what am talking about here.
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Post by brobear on Jan 4, 2020 12:40:03 GMT -5
www.ancient-origins.net/news-history-archaeology/prehistoric-beasts-0011853 3 MAY, 2019 - 22:49 ASHLEY COWIE Fossils of Giant Prehistoric Beasts Discovered in Underwater Ice Age Death Cave More than 10,000 years ago, as the last Ice Age ended, vast sheets of ice receded, scarring and causing massive cracks to appear on the bridge between North and South America. At that time, the land bridge was known to have been inhabited by fearsome beasts; now new evidence shows these prehistoric beasts included giant ‘wolf-like carnivores’ and the ‘largest bear’ ever to have walked on planet Earth. ‘10,000 BC’ was a 2008 American epic adventure film set in prehistory. It told the adventures of a prehistoric tribe of mammoth hunters. After its world premiere on February 10, 2008 in Berlin, although it was an immediate box office hit, the film became regarded by professional critics as one of the worst films of the year. The Sunday Times review section noted that the film was “archaeologically inaccurate and contains many factual errors and anachronisms.” But now it would appear this movie was based firmly in reality! A Death Pit of Giant Prehistoric Creatures At the bottom of an underwater cave in Mexico archaeologists have discovered an ancient graveyard including the skeletons of ancient sloths, sabretooth cats, cougars, elephant-like gomphotheres, bears, and dog-like animals. According to the researchers’ new paper, published in Biology Letters , they have recovered the skull of an enormous short-faced bear ( Arctotherium wingei ) and remains of a wolf-like dog known as Protocyon troglodytes. Furthermore, in 2007, researchers even found “two human skeletons dating to more than 12,000-years-old.” These are now thought to be two of the “oldest human skeletons ever found in the Western hemisphere” and they inform experts that our ancestors once lived alongside giant ground sloths, towering bears, and fierce wolf-like carnivores. The remarkable discoveries were made in the Hoyo Negro pit (Spanish: blackhole) in the Sac Actun cave system on the eastern coast of the Yucatán Peninsula . Researchers have described it as “an underworld of exquisitely preserved fossils” naturally formed from limestone in the Late Pleistocene. It is thought that animals fell nearly 60 meters (200 feet) into the death pit and when the melting glaciers filled the pit the remains became a permanent installation. This large-scale archaeological project is being financially support by a consortium including INAH (National Institute of Anthropology and History), National Geographic Society, the ETSU Center of Excellence in Paleontology, the Archaeological Institute of America, and DirectAMS and Strauss Family Fund. Among the bones recovered by scientists over the past 12 years, the team of US and Mexican researchers were most impressed by the remains of a giant bear and a wolf-like creature . While having been collected several years ago, both giant species were misidentified until now. But it’s not only the awe inspiring size of these two skeletons that is fascinating scientists, it’s the fact that they are causing anthropologists to redress their theories about ancient animal populations in South America . How so? Up until their correct identification, scientists were convinced that the short-faced bear and wolf only populated the southern aspects of the South American continent, “more than 2,000 kilometers away.” When Did these Prehistoric Beasts Travel Such Vast Distances? Lead author and paleontologist from the East Tennessee State University, Blaine Schubert, told reporters at Live Science , “The whole previous record of this particular type of bear is just known from a few localities in South America, and those are fragmentary remains.” And having come from almost no knowledge of this bear, the scientists now have what is being called “the best record of this type of bear from the Yucatán of Mexico.” Trying to account for how the bear and wolf got as far north as Mexico, scientists refer to “many cross-over events between North and South America.” Another possibility being proposed by the authors is that having walked all the way south, during or after the last full glacial event between 35,000 and 12,000 years ago, they returned northwards to the region of the cave. The scientists wrote, “We suggest that landscape and ecological changes caused by latest Pleistocene glaciation supported an interchange pulse that included Homo sapiens.” When 10,000 BC was released in 2008 critics at Variety wrote: “10,000 BC reps a missed opportunity to present an imaginative vision of a prehistoric moment.” However, in April 29, 2008 the movie had grossed approximately $268.6 million worldwide, which was said to be “dead money.” Now, it appears the movie was a really, really expensive archaeological lesson. Top Image: A diver holds the skull of an ancient bear known as an Arctotherium. It is one of the species of “prehistoric monsters” found in an underwater Yucatan cave. Source: Copyright Roberto Chavez-Arce By Ashley Cowie
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Post by brobear on Mar 25, 2020 4:37:07 GMT -5
BY Taipan - carnivora.net/arctotherium-angustidens-v-southern-elephant-seal-t8291.html#p107518 Arctotherium angustidens Arctotherium is an extinct genus of South American short-faced bears within Ursidae of the late Pliocene through the end of the Pleistocene. They were endemic to South America living from ~2.0–0.01 Ma, existing for approximately 1.99 million years. Their closest relatives were the North American short-faced bears of genus Arctodus (A. pristinus and A. simus). The closest living relative would be the Spectacled bear (Tremarctos ornatus). A specimen of A. angustidens from Buenos Aires shows an individual estimated, using the humerus, to weight between 983–2,042 kg (2,170–4,500 lb), though the authors consider the upper limit as improbable and say that 1,588 kg (3,500 lb) is more likely, however, using the radious, the mass estimate shrinks to a maximum of 1,108 kg (2,440 lb).
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Post by brobear on Jun 16, 2020 3:59:01 GMT -5
Kodiak: I'm well aware of those 1500+ kg estimates for Arctotherium. All of those estimates originated from the Soibelzon 2011 paper (that i linked above). It's needed to keep in mind that the mass figures for extinct animals are not actual mass of the animals but are just estimates (since all you got are fragments of their bones). The 1500 kg estimate for Arctotherium was obtained by using a slightly different methodology than the 1000 kg estimates for Arctodus simus. If you use the methodology from Soibelzon 2011 and apply that to the measurements of Arctodus simus, it's very likely that you could also obtain a figure of 1500+ kg for Arctodus. On the other hand, if you use the methodology in Figueirido 2010 (which was used to obtain the 1000 kg mass for Arctodus) and apply that to the measurements of Arctotherium, you would probably only get a figure of ~1000 kg. My point here is that, if you look at the bone measurements, there aren't any indications to suggest that Arctotherium was a much bigger bear considering that, as i said in my previous post, the largest Arctotherium's humerus is slightly shorter than the largest Arctodus's humerus. The humerus of the Arctotherium is more robust (has greater transverse/mediolateral diameter), however, humerus robustness is a bad predictor for body mass in Ursids ( Figueirido 2010, Table 2). You are free to take that 1500 kg figure for Arctotherium as it is because it's still the 'official' estimate for Arctotherium. However, if you look at the bone measurements of these animals and put them next to one another, there aren't any reasons to believe Arctotherium was any bigger than Arctodus. The great difference in mass estimates here is merely from the use of different methodologies. Here is a picture of Arctodus's humerus www.nps.gov/kova/blogs/ice-age-mammal-bones-of-northwest-alaska-5.htmLike i said, isn't any smaller than that of Arctotherium According to "tigerluver" over at Wildfact, ( a true Biologist ) these two giant short-faced bears were of equal size.
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Post by brobear on Jun 16, 2020 4:04:26 GMT -5
Arctodus simus and Arctotherium angustidens are the two biggest bears ever ( unless some new discovery is found ).
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Post by OldGreenGrolar on Jun 16, 2020 7:04:16 GMT -5
/\ Almost forgot about the picture above. The Ursus Maritimus Tyrannus looks more like a brown bear and the extant polar bear ranks no 6 in the same picture.
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Post by brobear on Jun 16, 2020 7:17:05 GMT -5
/\ Almost forgot about the picture above. The Ursus Maritimus Tyrannus looks more like a brown bear and the extant polar bear ranks no 6 in the same picture. The polar bear may be number #6, but he is listed among the biggest bears ever. The only thing on the picture I disagree with is... I would have placed the polar bear as number #5 and Agriotherium africanum as number #6. This because, while they are pretty-much the same size, I believe that the polar bear would be heavier due to his much-needed fat. Agriotherium living in Africa was probably a very lean bear.
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Post by OldGreenGrolar on Jun 16, 2020 7:19:31 GMT -5
The Agriotherium africanum at weight parity will still be longer than the polar bear and probably taller but not as bulky.
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Post by brobear on Jun 27, 2020 4:32:30 GMT -5
The Agriotherium africanum at weight parity will still be longer than the polar bear and probably taller but not as bulky. Actually, pretty-much equal in height and length, but I believe the polar bear would have some weight advantage. In competition for the biggest short-faced bear, Arctodus simus vs Arctotherium angustidens - the South American bear was ( IMO ) heavier due to his larger bones. In competition for the largest Ursus bear, Ursus Kanivetz / Ursus Ingressus vs Ursus arctos priscus / Ursus maritimus tyrannus - a 50-50 toss-up.
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Post by King Kodiak on Jul 25, 2020 21:02:19 GMT -5
SOUTH AMERICAN SHORT FACED BEAR (ARCTOTHERIUM ANGUSTIDENS) DISPLACING A SOUTH AMERICAN PLEISTOCENE JAGUAR (PANTHERA ONCA MESEMBRINA)
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