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Bears of the Pleistocene
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Two questions: I know that U. deningeri was an ancestral cave bear that looked very similar to a grizzly. I am wondering if perhaps U. speleaus and U. ingressus might actually be two subspecies of the same cave bear? My other question is; did U. ingressus have the short hind legs giving him the sloping back profile as we see in U. speleaus?
 (01-06-2018, 10:20 PM)brotherbear Wrote: Two questions: I know that U. deningeri was an ancestral cave bear that looked very similar to a grizzly. I am wondering if perhaps U. speleaus and U. ingressus might actually be two subspecies of the same cave bear? My other question is; did U. ingressus have the short hind legs giving him the sloping back profile as we see in U. speleaus? Anatomically, there isn't many comparison between speleaus and ingressus, assume they were very similar to each other, except the former one was more herbivorous, while the latter one was more carnivorous. But ingressus as a subspecies of spelaeus could also be viable, since these two Cave bear groups didn't have any geographical barrier that split them. BTW, all Cave bear species derived from the Etruscan bear population in Europe, while the Brown bear lineage evolved from the Etruscan bear population in China. So that's the difference between the basal ancestry of the Cave bear and Brown bear.
True or False information: The Ursus maritimus tyrannus ulna is from a sub-adult specimen?
dinopedia.wikia.com/wiki/Ursus_maritimus_tyrannus Ursus maritimus tyrannus is an extinct subspecies of the polar bear, known from a single fragmentary ulna found in the gravels of the Thames at Kew Bridge, London. It was named by the Finnish paleontologist Björn Kurtén in 1964 and is interpreted to represent a relatively large subadult individual: the ulna is estimated to have been 48.5 cm (19 in) long when complete. For comparison, modern subadult polar bear ulnae are 36–43 cm (14–17 in) long. An unpublished reinvestigation of the fossil suggests that the fossil is actually a brown bear. (01-07-2018, 06:55 PM)brotherbear Wrote: True or False information: The Ursus maritimus tyrannus ulna is from a sub-adult specimen? Not sure, only @tigerluver has more access of information than anyone else here. BTW, if it was really a subadult, then the Tyrant Polar bear is again back to the race for the title of the largest Ursidae in the history.
From the book - The Cave Bear Story by Bjorn Kurten: It is no surprise, then, to discover that the cave bear indeed had a much longer thigh, but a shorter shin and foot, than the brown or grizzly bear. Much the same holds for the front limb, in which the humerus ( upper arm bone ) is very long but the forearm and hand comparatively short.
*This means that we cannot fairly compare the ulna of Ursus maritimus tyrannus with that of the cave bear.
Wouldn't it be interesting if the grizzly were reintroduced into North Africa? After all, it was humanity which exterminated them long ago.
https://www.researchgate.net/publication...ssil_bones
This site will not copy, but very interesting information.
palaeo-electronica.org/content/2012-issue-2-articles/263-cave-bears-from-poland
Out of the big mammal species that went extinct during the Pleistocene, the cave bear is probably the most thoroughly genetically studied one. Its fossil material is quite abundant in cave sites across Europe and Asia, and in many cases preserved sufficiently well to allow ancient DNA (aDNA) extraction and analysis (e.g., Hänni et al., 1994; Loreille et al., 2001; Hofreiter et al., 2002, 2004a, 2004b, 2007; Orlando et al., 2002; Noonan et al., 2005; Valdiosera et al., 2006; Bon et al., 2008; Krause et al., 2008; Knapp et al., 2009; Stiller et al., 2010). Cave bears diverged from their sister lineage leading to the brown bear (Ursus arctos), approximately 1.2-1.7 million years ago according to palaeontological (Kurtén, 1968, 1976; Rustioni and Mazza, 1992; Rabeder and Withalm, 2006) and molecular data (Loreille et al., 2001; Bon et al., 2008), although some calculations indicate an earlier split about 2.8 million years ago (Krause et al., 2008). It is usually assumed that Late Pleistocene cave bears (Ursus ex gr. spelaeus) evolved gradually from the Middle Pleistocene cave bears from the deningeri-group still before the Last Interglacial (Mazza and Rustioni, 1994; Rabeder et al., 2000, 2010). The results of both morphological and genetic studies have shown that during the Late Pleistocene, Europe was inhabited by two main cave bear haplogroups described as separate species, U. spelaeus and U. ingressus (Rabeder, 1995; Hofreiter et al., 2004b; Rabeder and Hofreiter, 2004; Rabeder et al., 2004a, 2004b). They separated between 173,000-414,000 yr BP according to molecular dating (Knapp et al., 2009). Additionally, among U. spelaeus several high-alpine forms with reduced body size, named U. s. eremus and U. s. ladinicus, were discerned whereas the 'classic' Western Europe cave bear was called U. s. spelaeus (Rabeder et al., 2000, 2004a, 2004b, 2008; Hofreiter et al., 2004b; Rabeder and Hofreiter, 2004). For a recent review of most described cave bear taxa and a somewhat different conception of their classification based on craniometrical features see Baryshnikov and Puzachenko (2011). According to this study, the morphological differences between U. spelaeus and U. ingressus do not exceed subspecies level and are too small to consider them as different species. A large number of radiocarbon dates revealed that cave bears became extinct just before the Last Glacial Maximum (LGM), ca. 24,000 yr BP (27,800 cal. yr BP; Pacher and Stuart, 2009). Comparison of effective female population sizes of cave bears and their sister species, the brown bear, showed that the genetic decline of cave bears preceded their extinction by about 25,000 years, while brown bear population size remained constant (Stiller et al., 2010). The reason(s) for the extinction of cave bears are still unclear but it seems that not only one, but probably several causes played a role in its disappearance, possibly including climatic changes, human impact (Stiller et al., 2010), and predator stress caused by cave lion and cave hyena (Diedrich, 2010). The phylogeographic picture of cave bears in Eurasia does not offer clear indications of the migration routes of cave bears during the Pleistocene glacials and interglacials. It has been suggested that U. ingressus dominated mainly in Eastern and Central Europe while U. spelaeus did so in Western Europe (Hofreiter et al., 2004a; Knapp et al., 2009). In addition to this picture in Europe, remains of both species were also discovered in Asia (Knapp et al., 2009). 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). In fact, it was shown that U. ingressus immigrated into the Alps around 50,000 years ago where it replaced two former populations of U. s. eremus and U. s. ladinicus (Rabeder and Hofreiter, 2004; Rabeder et al., 2008). Similarly, the stratigraphically younger U. ingressus replaced quite suddenly the older U. s. spelaeus around 28,000 yr BP (32,000 cal. BP) in three geographically close caves in the Swabian Jura of Germany (Münzel et al., 2011). However, despite the numerous samples that have been genetically analysed so far, there are a number of regions from which no genetic data have been obtained so far and which could contribute to a better understanding of the complex picture of recent cave bear evolution. Although fossil remains of cave bears are quite common in Poland, i.e., north of the Carpathian and Sudetes Mountain ridges, no DNA analyses were so far performed on cave bear remains from this region of Europe. Such analyses would be an important step towards reconstructing a more complete picture of phylogeographic structure and genetic variation of cave bears sensu lato. In this paper we present the results of the analysis of cave bear specimens discovered in Niedźwiedzia Cave (Wiszniowska, 1976; Wiszniowska et al., 1996; Bieroński et al., 2009) located in the eastern Sudetes Mountains. Phylogenetic analyses were performed with a variety of methods to ensure that the obtained tree topology was not dependent on a specific method. *From this post: According to this study, the morphological differences between U. spelaeus and U. ingressus do not exceed subspecies level and are too small to consider them as different species.
Maybe the Carpathian Mountain was the boundary between Ursus spelaeus spelaeus and Ursus spelaeus ingressus.
The north of Carpathian Mountain belonged to spelaeus, while the south belongs to ingressus. According to the Ice Age Giants of BBC, the Cave bear ingressus had managed to kill and eat a Cave lion who ventured into its cave, and we could definitely assure that ingressus was much more aggressive than spelaeus.
The grizzly had it rough during the Pleistocene when you think about it. In North America, besides the assortment of horrific big cats, he had the giant short-faced bear to watch-out for. In Europe, the grizzly had to deal with cave hyenas, cave lions, and the giant mostly-carnivorous cave bear. I know very little about ( actually nothing ) about Pleistocene Russia. But the grizzly should get a medal-of-valor simply for surviving.
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About #247: yes you're quite right, the ultimate survivor medal should be awarded to the grizzly bear... Among the panthera athrox, the sabertooth cats, the short faced-bear, the prides of the great dire wolwes and so on in North America, the quiet nights had to be appreciated by these ursids...
Question: What is known about the original brown bears of Pleistocene China? Size, habitat, etc.
The shrinkage of brown bears - www.allgrizzly.org/
One interesting parenthetical observation about brown bears is that they seem to have diminished in size over the course of the last ice age (the Pleistocene). This was first observed by Bjorn Kurten, a world-famous Finnish paleontologist, based on measurements of fossil brown bear skulls collected in Europe. More recently, Adrian Marciszak and associates published results, also based on measures of bear skulls found in Europe, that seem to have pretty much nailed this trend. These results are summarized at left, arrayed according to time, from left to right, differentiating males from females and measures of skull length from skull width. (The acronym MP refers to "middle Pleistocene," progressing in time to the recent, "R"). One feature of these results is the suggestion that males dwarfed more substantially than did females. This begs the question: Why? Hemispheric patterns in the size of contemporary brown bears (see Morphology) suggest that bears are larger where they eat more protein, typically in the form of meat. There was certainly a lot of meat around during the Pleistocene, perhaps in the form of carrion able to be obtained from the carcasses of the numerous large herbivores dying from any number of causes (see History). According to Herve Bocherens, an expert on reconstructing diets from the analysis of ancient tissues, brown bears were especially carnivorous during the Ice Age, especially in the steppe tundra of Eurasia. This is all consistent with the larger size of Ice Age brown bears being a consequence of ingesting more meat. Even the differences between trends in male and female sizes is consistent with a meat effect given that males tend to eat comparatively more meat whenever it is available, which means they would have been comparatively more affected by the rapid decline of the meat resource caused by widespread extinctions of the large herbivores towards the end of the last Ice Age. |
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