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Post by brobear on Apr 1, 2017 16:48:25 GMT -5
The Eternal Frontier by Tim Flannery.
Tom Stafford has uncovered evidence that short-faced bears might have hung on for a little longer than other megafauna, surviving until 11,500 years ago on the southern prairie. Stafford and Russ Graham suspect that the bears made a marginal living hunting buffalo and were mostly avoided by human hunters. If so, the great carnivores were certainly relict by then - just as condors are today - and their extinction left the large-bear niche open in North America. The more versatile omnivorous brown bear or grizzly, with its long experience of human hunters, soon filled the continent in its wake. Unlike bison, no brown bears of any sort had inhabited North America before. Although brown bears and short-faced bears may have co-existed in Alaska ( the fossil record is equivocal ), it seems possible that competition from short-faced bears excluded the browns from North America south of the ice.
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Post by brobear on Apr 1, 2017 17:09:52 GMT -5
shaggygod.proboards.com/ "If short-faced bears were large, aggressive scavengers capable of stealing carcasses from other large carnivores, then it seems unlikely that brown bears could dominate them in direct interference competition. And while brown bears may have preferred to feed on animal carcasses, it seems more likely that they would have avoided direct confrontation with a dominant bear. The ecological plasticity of brown bears and their ability to hibernate may have been the keys to their ultimate survival at the end of the Pleistocene, while Arctodus, the highly specialized forager, was not able to find a niche in Holocene ecosystems. Most likely, carcass densities on Holocene landscapes fell below levels necessary to sustain minimal viable populations of short-faced bears. Since many bears hibernate to survive poor food availability during winter, this may be an indirect indication that short-faced bears, and perhaps all New World bears, never evolved this strategy to survive seasonal dietary bottlenecks.” Paul E. Matheus, 1995, Diet and co-ecology of Pleistocene short-faced bears and brown bears in eastern Beringia. Quaternary Research 44(3):447-453.
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Post by brobear on Apr 1, 2017 19:47:42 GMT -5
Short-Faced Bear meets Grizzly
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Post by brobear on Apr 5, 2017 12:35:40 GMT -5
IMO - I believe that the grizzly and the short-faced bears shared the American West for several thousand years. Just as the atrox, the saber-toothed cat, the scimitar cat, the giant jaguar, and other large-sized cats shared the environment, so did the big bears, Arctodus simus, the Florida cave bear, the grizzly, and the black bear. They simply found a way. Few fossil remains are found due the the presence of so many predators who scavenge and scavengers who hunt. A carcass would have been quickly consumed; bones and all. As for the fossils found in the La Brea tar pits, there were far fewer bears than wolves, big cats, or other predators and scavengers due to the intelligent bear's superior ability to observe and comprehend the hidden dangers. Less bears were trapped. Before the mass extinction which killed-off the multitudes of mega-beasts, I believe that grizzlies were living in western North America in reasonably large numbers from Alaska to Mexico. Somehow, they coexisted with the giant short-faced bears.
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Post by brobear on May 2, 2017 9:51:41 GMT -5
Both the giant panda and the Andean bear are somewhat more social than those of the genus Ursus. Not completely social comparable to wolves or lions, but they gather in social groups unheard of with the grizzly. This does not include anything similar to pack-hunting. In fact, both the giant panda and the Andean bear are mostly vegetarian. Sometimes females with cubs of both the panda and the Andean will gather among others of their kind; perhaps in a social nursary. Males of both species appear to be less social with each other. Perhaps in looking closely at the lives of these bears might give a little insight on the lives of the short-faced bears.
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Post by brobear on May 2, 2017 11:03:38 GMT -5
I believe, not from any fossil evidence but rather from simply having some understanding of the grizzly, that as more and more grizzly bears migrated south from Canada, that they simply outcompeted the short-faced bears by taking advantage of a much wider range of food choices and by having the ability to hibernate through the harsh winters when food resources were low. Probably, for the most part, the smaller grizzlies avoided the giants while consuming the flesh of carrion every chance they got. Even though the giants were also omnivores, I believe that carrion was their mainstay. I also believe that the grizzly hunted his own meat more often than the giants. This might also have included killing juvenile short-faced bears.
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Post by brobear on Jan 17, 2018 6:57:36 GMT -5
Giant short-faced bear - built like a camel with a heavy body riding upon long comparatively slender legs. Built for long-distance walking but could run camel-fashion in a relatively straight line. The giant could not safely make high-speed quick twists and turns as needed by a true-predator without being in danger of receiving a broken leg. Grizzly - built like a huge badger or raccoon - Could run fast and safely make the necessary quick twists and turns while in pursuit of prey. Both bears were omnivores who spent considerably long time periods feeding on vegetation. But, both bears also consumed huge amounts of meat. The giant as the top-of-the-food-chain scavenger. The grizzly as a top predator and as a scavenger as well.
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Post by brobear on Jan 20, 2018 8:40:43 GMT -5
www.researchgate.net/publication/249180878_Two_Fossil_Grizzly_Bears_from_the_Pleistocene_of_Oklahoma These two discoveries of grizzly fossils in Oklahoma prove that YES there were grizzlies coexisting with the giant short-faced bears out on what is now the American prairie. There were grizzlies living out among the mega-fauna. For those grizzlies, life was harsh. Especially with the smaller she-bears with cubs. The giant was a well-adapted scavenger. The grizzly very likely did more hunting than scavenging. In this way, they coexisted. Also, the grizzly fed on much more vegetation than the giant and had many other food choices, which cut down on carcass-competition. The grizzly was more heavily populated in the more remote locations where a bear cub had a better chance of survival into adulthood.
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Post by Polar on Jan 20, 2018 16:51:01 GMT -5
One must think what other animals the short-faced bear met while in the southern US or north South America: car-sized Josephoartigasia, smaller capybaras, peccaries, giant camels, smaller carnivores, giant bison, black bears, maybe some Paleolithic Amerindian natives, and a whole bunch of other creatures.
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Post by Polar on Jan 20, 2018 16:53:03 GMT -5
One of Arctodus's potential prey animals, Josephoartigasia:
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Post by brobear on Jan 21, 2018 0:15:30 GMT -5
Had to look that one up. At 1,000 kg ( 2,205 pounds ) he was probably the biggest-ever rodent. But, he lived in South America, home of Arctotherium angustidens. I have to wonder what it is ( or was ) about S. America to produce such giants? Biggest rodents, biggest bears, biggest Smilodon and biggest dinosaurs.
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Post by brobear on Jan 21, 2018 0:31:18 GMT -5
Biggest rodent of N. America - probably prey of the grizzly - www.prehistoric-wildlife.com/species/c/castoroides.html Castoroides Name: Castoroides. Phonetic: Cass-tor-oy-dees. Named By: John Wells Foster - 1838. Synonyms: Castoroides nebrascensis, Burosor efforsorius. Classification: Chordata, Mammalia, Rodentia, Castoridae, Castoroidinae, Castoroidini. Species: C. ohioensis (type), C. leiseyorum. Diet: Herbivore. Size: Largest individuals up to 2.2 meters ( 7 feet long ), not including the tail. Known locations: Canada - Ontario, Yukon. USA - Alabama, Florida, Georgia, Illinois, Iowa, Kansas, Michigan, Nebraska, New Jersey, Ohio, Oklahoma, Pennsylvania, South Carolina, Tennessee, Virginia. Time period: Mid Calabrian of the Pleistocene through to the early Holocene. Fossil representation: Multiple individuals. Castoroides is another example of how back in the Pleistocene animals were just bigger than they were today. Also known as the ‘giant beaver’, Castoroides is not just the largest beaver that we currently know about, but it is the largest rodent known to have ever lived on the North American continent. At the time of writing the only rodents known to have been bigger than Castoroides are Phoberomys and Josephoartigasia from South America. Unfortunately no clear irrefutable evidence exists that proves that Castoroides built dams like modern beavers. Structures that might represent the prehistoric remains of such structures can also be explained away as other things such as flood deposits or naturally occurring accretions. Available evidence actually supports the theory that Castoroides did not build dams given that their incisors were not as well suited to cutting into wood as modern beavers have. However related genera do seem to have built lodges, which by association might indicate that Castoroides too also built lodges. The extinction of Castoroides has for a long time been shrouded in mystery. While the disappearance of much of the North American Megafauna has been attributed to such factors as extreme glaciations, climate change, super volcanic eruptions, asteroid strikes, human hunting and combinations of all the above, Castoroides populations are actually known to have been in decline before this mass extinction took place. This has meant that the exact cause for the extinction of Castoroides has been unknown for almost two hundred years, but there may now be one idea which might go some way to explaining things. A 2011 paper by J. T. Faith detailed how nitrogen levels in the soil were declining at the time that Castoroides numbers were also declining. Reduced levels of nitrogen in the soil cause a reduction in growth and nutritional quality of plants that require high nutrient levels. Herbivorous animals that rely upon such plants end up having to eat even greater amounts of them to maintain there population, but this results in even less nitrogen going back into the soil as leaf litter. This further reduces the crop of nitrogen rich plants the following year, which means even more had to be eaten, and again this made the problem much worse again the following year, and so on and on again until the ecosystem collapses and is unable to support the presence of such herbivorous. It Castoroides preferred eating plants that required high levels of nitrogen, then they would over successive seasons and generations slowly deplete available food plant supplies. Thus, unable to adapt to eating different plants, Castoroides may have ended up starving themselves into extinction.
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Post by Polar on Jan 21, 2018 1:58:55 GMT -5
Oops, sorry for the mistake. Yeah, the Josephoartigasia lived in South America, not southern US too.
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Post by brobear on Apr 1, 2018 6:52:48 GMT -5
There are several ideas ( theories ) on the relationship between grizzly and arctodus simus. Some historians/paleontologists believe that as the grizzly populated and spread throughout western N. America, arctodus simus was displaced. Still others believe that the grizzly remained a rare animal during this Ice Age roaming only in very remote locations for fear of the giant short-faced bear. I have my own theory. With a multitude of large predators lurking about, the short-faced bear never had a need to hunt and kill large prey animals. A grizzly could very easily avoid being too close to the giant bear. These two big bear species very likely, for the most part, ignored each other. What grizzlies did have to contend with were wolves and big cats. Besides the grey wolf there were also larger dire wolves. Also, giant jaguars, atrox lions, scimitar cats, and the famous saber-toothed cats. Life was without any doubts extreme for a mamma bear with cubs. Not even a full-grown mature grizzly boar was safe from a pride of sabertooths,
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Post by Deleted on Apr 1, 2018 7:35:30 GMT -5
If these two bears possibly coexisted, do you think that short faced bear possibly preyed on the grizzly?
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Post by brobear on Apr 1, 2018 10:11:55 GMT -5
No, despite this being said so often, I don't think so. My reasoning: Arctodus simus was ( as is widely believed ) an omnivore that leaned heavily towards a meat diet. He was not built for predation as you can see from data given right here on the Domain. He was an accomplished scavenger. The grizzly during the Pleistocene was probably much more predator than the giant. The grizzly is too smart than to challenge the giant or to accept a challenge from the giant over a carcass. All the grizzly had to do was to keep a safe distance between himself and the giant, just as a smaller grizzly keeps a safe distance from a big dominant grizzly in the wild today. It is widely believed that the giant did not give chase to prey animals.
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Post by brobear on Sept 8, 2018 5:41:55 GMT -5
My opinion ( pure speculation ), the big cats, those which were group-hunters, which included the saber-toothed cat, Smilodon fatalis and perhaps also the giant American lion, Panthera leo atrox, were the real danger to the Pleistocene grizzly. The grizzly could easily elude the giant short-faced bear which ( IMO ) was not a hunter. But grizzly juveniles and probably full-grown grizzly she-bears were very likely prey choices for a pride of large big cats. I do not think that they hunted full-grown grizzly boars; but this is merely my opinion. It is obvious that the grizzly was in some way capable of co-existing with a dramatic multitude of very large predators in western Pleistocene North America. He ( and she ) were there.
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Post by brobear on Sept 16, 2018 4:48:09 GMT -5
Arctodus simus had comparatively light-weight limb bones; gracile for a bear. His feet pointed straight rather than the bulldog like posture of a grizzly. Nevertheless, Arctodus simus is nicknamed the "bulldog bear" for his short muzzle. This giant short-faced bear was not a runner but rather a long-distance walker who could cover ground rapidly ( in a straight course ) in a camel-like trot. Arctodus simus was not a hunter - not a predator but rather an accomplished scavenger. He probably bluffed his way to a carcass more often that fight his way. His front limbs are not well adapted for grappling as are those of the Ursus genus. Arctodus simus has minimal sexual dimorphism, which would suggest that these bears ( males ) seldom fought for a mate. They were not grapplers. Arctodus simus was ( IMO ) an omnivore who leaned heavily towards a diet of found or taken carcasses. His bite-force was far superior to that of a Pleistocene grizzly. But, I strongly believe that there was very little interaction between these two bear species. A grizzly could easily avoid the giant. Pound-for-pound, a grizzly is much stronger; but the giant simply had too many pounds for a grizzly to challenge.
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Post by brobear on Oct 4, 2018 15:42:57 GMT -5
www.sciencedirect.com/science/article/pii/S0016699517300384 Climate change and human impacts are often implicated in Quaternary megafaunal extinctions. The discovery of associated remains of extinct giant short-faced bears (Arctodus simus) and invading brown bears (Ursus arctos) raises the possibility of competition as another potential factor. We describe fossil remains of both genera from Pellucidar Cave, Vancouver Island, Canada. Analyses of ancient mitochondrial DNA support the identifications of post-cranial brown bear specimens and assign these bears to Clade 4. Our results are consistent with the migration of brown bears from Eastern Beringia to the contiguous United States before the Last Glacial Maximum (LGM) and to Vancouver Island as environmental conditions became favorable after the LGM. Radiocarbon age estimates on these specimens indicate the presence of giant short-faced bears approximately 13.5 thousand calibrated years before present (cal. ka BP; uncalibrated 11,775 ± 30, 11,720 ± 50, and 11,615 ± 30 BP) and of brown bears immediately preceding (∼14.5 cal. ka BP; 12,440 ± 35, 12,425 ± 30 BP) and following this time (∼13 cal. ka BP; uncal. 11,100 ± 30 BP), suggesting niche partitioning to reduce competition among these species. We suggest that shifts in food availability or quality due to post-glacial vegetation and faunal changes were probably of primary importance in the arrival and the disappearance of giant short-faced bears on Vancouver Island. This study focuses on a key time period and geographic location that is useful in understanding Pleistocene extinctions in North America.
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Post by brobear on Oct 4, 2018 15:51:46 GMT -5
ABOVE POST continued.... 1. Introduction During the Pleistocene, the giant short-faced bear Arctodus simusCope, 1879, was found across North America, both in the continental United States (U.S.A.) and in Beringia (Kurtén and Anderson, 1980), the isthmus that was exposed between Alaska and Asia during glacial periods. As the Pleistocene ended, giant short-faced bears became extinct, with latest known fossil specimens dated to approximately 10.9–10.7 ka BP, i.e., ∼12.7 thousand calibrated calendar years before present (cal. ka BP), from Kansas, Texas, and Utah (Madsen, 2000, Schubert, 2010). These large bears were one of 17 late Pleistocene genera to go extinct in North America after 12 ka BP (Grayson, 2015) as climate changed and human presence increased so that these factors are often implicated in the extinctions (Barnosky et al., 2004, Grayson, 2007, Grayson, 2015, Meltzer, 2015). Here we focus on an additional potential factor: the role of competition with brown bears Ursus arctosLinnaeus, 1758, in the extinction of giant short-faced bears. In what is now the continental U.S.A., giant short-faced bears may have been out-competed by invading brown bears as the latter expanded southward from Beringia (Kurtén and Anderson, 1974). Some evidence for this hypothesis comes from Eastern Beringia, where brown bears date from ∼48 to ∼7 ka BP with a gap in radiocarbon dates from ∼34 to ∼20 ka BP, and where giant short-faced bears date from ∼44 to ∼20 ka BP that likely marked the end of the genus in this region (Harington, 2003: pp. 381–383). Stable isotope analysis of fossil bone shows that brown bears shifted to a more carnivorous diet around 20 ka BP compared to their pre-35 ka BP predecessors, suggesting that brown bears could have competed for resources with giant short-faced bears in that region (Barnes et al., 2002). To address the competition hypothesis, we report an association of brown bear and giant short-faced bear bones from Pellucidar Cave on Vancouver Island, British Columbia (B.C.), in southwest Canada. We present new radiocarbon age estimates to determine the temporal relationship between these species at this locality and examine if inter-species competition for territory may have been a factor in the local extirpation of these bears. Additionally, for information about the biogeography of brown bears to that of short-faced bears, we obtained ancient mitochondrial deoxyribonucleic acid (aDNA) data from three brown bear specimens and use them in an attempt to discover the origin of ancient brown bears on Vancouver Island. The two nearest extent populations of brown bears represent genetically distinct mitochondrial DNA clades. Contemporary populations from north of Vancouver Island along the B.C. coastline and from central interior B.C. carry Clade 3b (Miller et al., 2006), which is also found across continental Alaska and the Yukon. In contrast, populations to the east and south of Vancouver Island belong to mitochondrial Clade 4, as do all populations from southern Canada and the contiguous U.S.A. The ancestors of Clade 4 likely migrated south from eastern Beringia between 89 and 35 ka BP (median ∼56 ka BP; Leonard et al., 2000, Barnes et al., 2002, Davison et al., 2011, Edwards et al., 2011). The last Alaskan individuals related to this group dates to ∼36 ka BP (Barnes et al., 2002, Edwards et al., 2011), and a Clade 4 individual from Edmonton, Alberta, dates to ∼26 ka BP (Matheus et al., 2004), indicating a biogeographic track east of the Rocky Mountain Range. The documented historic range of brown bears (Miller et al., 2006: Fig. 3a) indicates Vancouver Island is within the narrow region where the Clade 3b and Clade 4 groups nearly connect. This distribution allows us to test whether the ancestors of the Pellucidar Cave brown bears originated as Clade 3b from central and northern B.C., where giant short-faced bears are not known, or as Clade 4 from an eastern and/or southern continental source where giant short-faced bears occurred (Richards et al., 1996).
We describe some of the first ancient brown and giant short-faced bear specimens from Vancouver Island (see also Steffen and Harington, 2010, Steffen, 2016), and discuss these specimens in the contexts of possible competitive interactions, the effects of a changing environment, and implications for humans to gain insights into the causes of the extinction of the giant short-faced bear Arctodus simus.
2. Geologic setting 2.1. Locality Pellucidar Cave (1:50,000 NTS map sheet 092L07) is located on northeast Vancouver Island (Fig. 1) near the north edge of the Vancouver Island Ranges physiographic unit and south of the Nahwitti Lowland (Holland, 1976, Howes, 1983). The cave comprises a series of passages in Quatsino Limestone (Nixon et al., 2006), at approximately 600 m elevation above sea level, on the eastern slopes of Nimpkish Lake. Nagorsen and Keddie (2000), Harington (2011), and Steffen (2016) provide information about the locality that includes two entrances. The Pellucidar II opening, referred to in this paper as Pellucidar Cave, is a rubble-choked entrance situated on steep terrain at the base of a steep cliff face. 2.2. Stratigraphy Bone specimens were located on the ground surface of the inward-sloping main passage, within 60 m of the entrance to the cave, amongst angular roof-fall and limestone and exotic (primarily granitic) sub-rounded boulders and cobbles that were a former streambed. Survey, mapping and then collection resulted in the assemblage of bone specimens reported here (Fig. S1, Appendix B). Each of the brown bear specimens was found at a separate location on the passage floor and these specimens represent at least two individuals. Giant short-faced bear specimens are the partial remains of one individual found as a concentration of bone fragments amongst fluvial deposits.
3. Material and methods 3.1. Material Bone specimens are portions of a cranium (PC2-1a-d and PC2-7) and a partial humerus (PC2-3) of a giant short-faced bear (Arctodus simus; Fig. 2), as well as a partial femur (PC2-2), the distal portion of a humerus (PC2-11), and the humerus of an immature individual (PC2-13) of brown bear (Ursus arctos; Fig. 3). Specimens described in this study are housed in the permanent collections of the Royal BC Museum in Victoria, B.C., Canada, and have assigned RBCM catalogue numbers as noted. A list with institutional abbreviations of comparative specimens examined in this study is provided in Appendix A. Final genetic sequences have been entered into GenBank under the accession numbers JX448567–JX448569.
3.2. Measurements Measurements follow Merriam and Stock (1925), Kurtén (1967) and von den Driesch (1976). Additional measurements are of the entepicondylar foramen of humerus PC2-3, and the minimum length of diaphysis measured from base of the proximal articular surface to the capitulum of humerus PC2-13. Measurements of femur PC2-2 include the minimum anteriorposterior diameter of the diaphysis, minimum length from the trochanteric fossa to the intercondyloid fossa, and minimum depth at the center of distal articular surface. Measurements of the alveoli of the maxilla fragment are also given.
3.3. Radiocarbon dating Six radiocarbon samples were obtained from the Pellucidar Cave bear specimens (Table 1). Two samples on giant short-faced bear (PC2-1c and PC2-3) and three samples on brown bear (PC2-2, PC2-11, and PC2-13) were sent to the Keck Carbon Cycle Accelerator Mass Spectrometry (AMS) facility at the University of California, Irvine. Radiocarbon was measured on ultrafiltered (> 30 kD) collagen according to Brown et al. (1988) and Beaumont et al. (2010). Results have been corrected for isotopic fractionation according to the conventions of Stuiver and Polach (1977), and δ13C values were measured on prepared graphite with AMS. A sample of dentine from the posterior labial root of the M2 of the maxilla fragment (PC2-1a) was sent to a second lab, the Oxford Radiocarbon Accelerator Unit in the Research Laboratory of Archaeology and the History of Art at Oxford, United Kingdom, where the chemical pretreatment, target preparation and AMS measurements follow Bronk Ramsey et al. (2004). Radiocarbon ages were converted to calendar ages with the IntCal13 calibration curve (Reimer et al., 2013) using the OxCal 4.2 radiocarbon calibration software (Bronk Ramsey, 2009). Lab # Specimen # Material δ13C C:N atomic 14C age BP 2σ cal. age ranges (BP) UCIAMS 41052 PC2–13 Ursus arctos - immature humerus –22.6 3.17 11,110 ± 30 13,082–12,845 UCIAMS 41049 PC2–1c Arctodus simus - palatine –18.8 3.16 11,615 ± 30 13,557–13,379 OxA 24005 PC2–1a Arctodus simus - M2 –18.6 — 11,720 ± 50 13,715–13,440 UCIAMS 41048 PC2–3 Arctodus simus - humerus –18.7 3.22 11,775 ± 30 13,725–13,477 UCIAMS 56479 SC-1 Ursus americanus - cranium –21.0 3.20 11,935 ± 40 13,964–13,575 UCIAMS 41050 PC2–2 Ursus arctos - femur –18.1 3.19 12,425 ± 35 14,836–14,211 UCIAMS 41051 PC2–11 Ursus arctos - humerus –18.8 3.19 12,440 ± 35 14,888–14,239 3.4. Ancient DNA isolation, amplification, and sequencing Bone samples removed from specimens of giant short-faced bear (PC2-3), and brown bear (PC2-2, PC2-11, and PC2-13) were processed using standard aDNA protocols, including the use of extraction and PCR negatives (Gilbert et al., 2005). Sample storage, aDNA extraction and polymerase chain reaction (PCR) set-up was performed in a dedicated aDNA facility at Penn State University that is physically isolated from modern PCR products and downstream genetic work. aDNA was isolated from the specimens following Rohland and Hofreiter (2007). For the three brown bears, a segment of the mitochondrial control region was PCR amplified in a 25 μL reaction comprising: 2 mg/mL rabbit serum albumin, 1X Amplitaq Gold 360 buffer (Applied Biosystems Inc., Foster City, California), 1.25 U Amplitaq Gold360, 250 μM each dNTP, 2.5 mM MgCl2, 1 μM each primer URSUSF1–136–156 (Valdiosera et al., 2007) and H16299 (Hänni et al., 1994). Cycling conditions were used as per the manufacturer's instructions with a 58 °C annealing temperature. The PCR product was cleaned using Millipore Multiscreen PCRμ96 filter plate (Millipore, Billerica, Massachusetts) and directly sequenced using BigDye v3.1 sequencing chemistry (Applied Biosystems) and the same primers as for amplification. Sequences were purified using ethanol precipitation and resolved using an Applied Biosystems 3730xl capillary sequencer at the University Park Genomics Core Facility (Penn State University). Two short (60 bp and 135 bp) fragments internal to the longer fragment were amplified and sequenced as in Barnes et al. (2002). No mismatches were identified between overlapping fragments. The final sequences were 275 bp (PC2-2), 253 bp (PC2-13), and 295 bp (PC2-11) long. No endogenous DNA could be recovered from the short-faced bear specimen, PC2-3, using as short as a 60 bp fragment (Hänni et al., 1994).
3.5. Genetic analysis The NCBI BLAST program was used to genetically identify the specimens as brown bear. The sequences were aligned to other modern and ancient brown bear and polar bear Ursus maritimusPhipps, 1774, control region sequences available from GenBank (Table S1, Appendix B). The intraspecific relationships of the specimens were determined using BEAST v.1.8.2 (Drummond and Rambaut, 2007). The HKY+G model of nucleotide substitution was selected using ModelTest (Posada and Crandall, 1998) and a flexible coalescent prior, the Bayesian skyline plot (Drummond et al., 2005), was used with 10 groups. Mean AMS radiocarbon dates for ancient specimens were used to calibrate the clock. Three Markov Chain Monte Carlo (MCMC) chains were run for 100 million generations each, subsampling every 10,000 generations and discarding the first 10% of samples as chain burn-in. Remaining samples were combined in LogCombiner. Effective sample sizes and MCMC convergence were assessed using Tracer v1.6 (Rambaut and Drummond, 2007) and the maximum clade credibility tree (Fig. 4; Fig. S2, Appendix B) was summarized using TreeAnnotator.
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