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Bears of the Pleistocene
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http://www.fs-media.net/kunden/ka/wp-con...rticle.pdf
4 Conclusion In this study species separation was possible on the above listed postcranial elements of 2,295 specimens of Ursus deningeri and Ursus spelaeus, in contrast to some studies on dental material (GRANDAL D’ANGLADE & LÓPEZ-GONZÁLEZ 2004). Ursus spelaeus was distinguished by the shortened and narrowed humerus, radius and femur, also by a shrinkage of the elbow and knee joints. This meant a change in proportion of the proximal to the distal skeletal elements. Ursus deningeri shows shortening and narrowing mainly of the metapodials, especially of the metatarsals. The characteristics of Ursus deningeri and Ursus spelaeus which grew smaller during the course of time are interpreted as an allometric phenomenon, showing a negative correlation to body size. The species-separating differences are shown in these predominantly differing characteristic allometric features. Interestingly, species classification and factor extraction was possible especially with measurements of the proximal and distal joint surfaces. The mean values of the data sets analysed here also show that Ursus spelaeus was generally larger than Ursus deningeri. This is in accordance with present assumptions (EHRENBERG 1939, RABEDER 1989, RABEDER & HOFREITER 2004, SANTI et al. 2003). EHRENBERG’s assumption that Ursus spelaeus could not have been particularly specialized, more likely omnivorous (EHRENBERG 1962), was proven false by BOCHERENS using isotope analysis (BOCHERENS et al. 1994). Carnivorous food acquisition requires a higher degree of agility and mobility than is necessary for a purely herbivorous diet (PETRONIO et al. 2003). Leney associated pronounced gracility with a largely carnivorous diet and ungainliness with herbivory (GITTLEMAN ATHEN, K. Statistical analyses on skeletal elements of Ursus deningeri and Ursus spelaeus 158 1985, LENEY 2000). This supposition is reinforced both by the isotopegeochemical analyses of bone collagen from Ursus spelaeus and by the morphology of the molars. The weight-supporting elements were strengthened, especially the anterior extremities, which would have probably been used increasingly to dig for roots and other food. It may be that Ursus spelaeus´ diet was specialized on certain types of plants. The interpretation of the observations in this study is that the factor behind the differences, the cause, is a change in locomotion habits. This was associated with increased herbivory and a genetic change, possibly due to migration. It could be, that the ursids retreated south (southeast or southwest) and reimmigrated later in a more developed form. Climatic influence and subsequent changes in alimentation are also conceivable. The question of whether or not Ursus deningeri and Ursus spelaeus share a common genetic line was addressed by the discriminant analysis of the factor values. The results show a significant difference in only seven of the almost fifty different statistical operations. The interpretation of the data used in this study, is that the affiliation of Ursus deningeri and Ursus spelaeus is so close as to imply a common line of descent. The majority of 108 fossil finds, mostly from the old diggings from the Einhornhöhle points towards a dominance of the Ursus deningeri-morphology group. Findings from each species originated during a long time period. There are different explanations for this observation. The fossil finds probably accumulated over a long geological time span. Perhaps it was the period of time, when Ursus spelaeus relieved Ursus deningeri. Possibly the specimens show the transition interpretation according to Rabeder (VON KOENIGSWALD & HEINRICH 1999) or a local variety (RODE 1935) or another species, which wasn’t included in this study (RABEDER & HOFREITER 2004). Apparently the Einhornhöhle was, over a long time span, populated mainly by the geologically older Ursus deningeri, whose remains during the course of sedimentation became mixed with those of the younger Ursus spelaeus.
Ursus deningeri (Ursus deningeri Richenau, 1904) http://prehistoric-fauna.com/Ursus-deningeri
Order: Carnivora Family: Ursidae Dimensions: length - 2,5 m, height - 135 сm, weight - 150-600 kg Temporal range: Pleistocene of Eurasia Ursus deningeri (Deninger's bear) is an extinct species of mammal of the family Ursidae (bears), endemic to Eurasia during the Pleistocene for approximately 1.7 million years, from ~1.8 Mya to 100,000 years ago.The range of this bear has been found to encompass both Europe and Asia, demonstrating the ability of the species to adapt to many Pleistocene environments. U. deningeri is a descendant of U. savini and an ancestor of U. spelaeus. Ursus deningeri has a combination of primitive and derived characters that distinguishes it from all other Pleistocene bears. Its mandible is slender like that of living brown bears and Ursus etruscus. It also has derived characters of cave bears (Ursus spelaeus) and is considered to be the descendant of Ursus savini and very close to the common ancestor of brown bears.
http://prehistoric-fauna.com/Ursus-ingressus
Ursus ingressus Order: Carnivora Family: Ursidae Dimensions: length - 2,3 m, height - 125 сm, weight - 100-300 kg Temporal range: Pleistocene of Europe "Whereas U. spelaeus inhabited mainly low and medium elevation areas, U. ingressus has mostly been found in medium and high elevated regions (Baryshnikov and Puzachenko, 2011). Recent isotopic analyses showed also some dietary differentiation between these cave bear haplogroups (Bocherens et al., 2011; Dotsika et al., 2011). Ursus ingressus was likely better adapted to continental environments and, thus, might have outperformed U. spelaeus during cold and arid climate conditions (Baryshnikov and Puzachenko, 2011). " The vast majority of fossil remains in Late Pleistocene deposits from Niedźwiedzia Cave in Kletno, Sudetes, Poland, belong to the cave bear. Phylogenetic analyses based on a fragment of the mitochondrial D-loop region extracted from two cave bear samples unambiguously showed their close relationship with the Ursus ingressus haplogroup. This taxonomic affiliation of the cave bear remains from Niedźwiedzia Cave was further confirmed by biometrical analyses of molar teeth and skulls. Our results represent the first record of U. ingressus north of the Carpathian Arch, while radiocarbon dating (> 49,000 yr BP) of the samples indicates that they represent some of the oldest specimens of this cave bear taxon known so far. Multi-method phylogenetic analyses including numerous publicly available cave bear sequences allowed analysing the relationships among these samples in details, including the significance of particular clades, and discussing some aspects of cave bear phylogeography. The sequences of U. ingressus from Poland are most closely related to specimens from the Ural Mountains and next to Slovenia, which may indicate migrations between Central and Eastern European populations. The internal placement of Ural Palaeoclimatic information from isotopic signatures of Late Pleistocene Ursus ingressus bone and teeth apatite (Loutra Arideas Cave, Macedonia, Greece). 
Holotype skulls, stratigraphy, bone taphonomy and excavation history in the Zoolithen Cave and new theory about Esper’s “great deluge”
From the study:  *This image is copyright of its original author This study touches on a few of those non-spelaea cave bears. Not sure where mass estimations produced by that website come from. It is difficult finding data on such species. 
Ursus deningeri was likely the predecessor for both Ursus spelaeus and Ursus ingressus.
BTW, the first member of the Brown bear clade was Ursus etruscus; its European branch gave the birth of Ursus deningeri, while its Asian branch gave the birth of Ursus arctos.
I notice that Ursus ingressus has the noticeable forehead of the true cave bear.
Because those massive Romanian Cave bears with huge skull and canine teeth were in fact Ursus ingressus.
That's why you got the initial impression that they were representative of the true Cave bears.
I wonder if there might have been some direct competition between the grizzly, Ursus arctos and either or both cave bears, Ursus spelaeus or Ursus ingressus? We will probably never know.
Ursus spelaeus were gentle teddy bears and would probably co-exist peacefully with other bear species.
While Ursus ingressus and the giant European Pleistocene Brown bears would probably attack each others. The giant European Brown bears from the mid-late Pleistocene were also larger and more carnivorous than the modern Brown bears.
So @
Quitting isn't my forte, so I'll make something out of the skulls. Before that, let me know which species you think will be morphologically most closely related to the extinct ones you'd like on the comparison photo. I'll use those to extrapolate comparisons. (10-12-2016, 12:13 AM)tigerluver Wrote: So @ That's pretty tough. The polar bear we have living, but the nearest bear we have to the cave bear ( Ursus spelaeus ) is perhaps a Kodiak. As for the Florida cave bear, his closest living relative is the Andes bear. Agriotherium africanum has no living relatives. If any of these must be left out, I completely understand. In fact, if the project proves to be too much trouble, I will certainly hold no hard feelings. I highly appreciate your efforts.
http://www.domeara.org/2013/05/the-extinction-of-the-irish-brown-bear/
The extinction of the Irish brown bear A new study by Saoirse Leonard and co-authors from the Institute of Zoology, London and the University of Liverpool model the potential survival of brown bears in an Irish glacial refugium. The study has just been published in Biology Letters. The study examines the presence of the now extinct brown bear (Ursus arctos) in Ireland during the Last Glacial Maximum (between 15,000 and 24,000 years ago) and aims to address the possibility that bears survived in Ireland during this period. The question has arisen because there is still lengthy debate as to whether Ireland remained partially ice free during the last glaciation, and if so, how many species, if any, survived in this ice free refugium? Recent work suggests that brown bears in Ireland hybridised at some point with polar bears (Ursus maritimus), and dating this potential period of overlap between the species is of interest. Although there has been suggestion that brown bears survived in Ireland up to about 3000 years ago, it is not known what the potential for overlap was to allow the meeting of both polar and brown bears in Ireland. See Edwards et al. (2011).To help address this, Leonard et al. conducted population variability analysis to ascertain the possibility of the brown bear surviving in Ireland during the last glaciation. The programme is designed to work with wildlife populations that have long life spans and low reproductive rates, making it suitable for use with the brown bear. The study gathered data from modern day brown bear populations including population statistics, the rate of reproduction and incorporated habitat variables. The authors built a model based on the assumption that during the last glaciation, an ice free habitat in Ireland would have been similar to Thundra regions today, and hypothesised a glacial refugium of approximately 29,000 square kilometers assuming 14,000 km ice free landmass on the present day Ireland, with the remainder landmass off shore and now submerged under water due to the subsequent rise in sea-levels since that period. The model assumed that Ireland had a maximum population of just over 500 individuals and assumed that Ireland was a barren landscape, with a median home range size of modern bears. The results showed that brown bears in Ireland were highly unlikely to have survived the last ice age. The models predicted that extinction occurred very quickly during the last glaciation with the likelihood that the bears died out some time between 150 – 1500 years during the last ice age period. The authors suggest that based on their model, that brown and polar bears must have hybridised before the last glaciation (around 25,000 years ago), or after the ice-sheet retreated and a chance opportunity arose for the two species to meet (around 10,000 years ago). Although the authors also admit that brown bear behaviour changed during the last glaciation, with the possibility that brown bears semi-adapted to ice sheet habitats and opportunistically mated with polar bears during transition periods prior to extinction. The authors believe that even if ice free areas did occur within Ireland, they would have been too small to support a brown bear population for any lengthy period, and the bears would have simply died out. Interestingly, there is suggestion in the paper that present day brown bear populations are at a similar risk of extinction due to the isolation of populations caused by habitat fragmentation and human prosecution. Models such as the one used in this study have the potential to be used to predict the long-term survival ability of such populations and could be used to help manage these threatened populations before they end up in the history books like the Irish brown bear.
That's why the Tyrant Polar bears weren't really extinct, their mtDNA is still remaining within the modern Polar bears.
Only their Y-DNA (Irish Brown bear) was completely gone without any carrier left.
The largest known skull for Arctodus simus, about 521 mm in the GSL.
It also belongs to its largest subspecies.  *This image is copyright of its original author  *This image is copyright of its original author
@tigerluver
What do you think about those giant Cave bear (Ursus ingressus) specimens discovered in the countries of the former Yugoslavia? The largest basal length is about 485 mm which points toward a 600 mm skull, do you think this is an estimation of the range or an actual measurement?  *This image is copyright of its original author Also, what about those two alleged 56 cm skulls in Austria and Slovenia? http://chestofbooks.com/crafts/scientific-american/sup4/Skeleton-Of-A-Bear-Found-In-A-Cave-In-Styria-Austria.html http://www.dedi.si/dediscina/156-krizna-jama |
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