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Post by grrraaahhh on Mar 4, 2013 17:42:12 GMT -9
@ duanmianxiong & @ divingwolf, this is a good thread. Please do not see my absence or lack of participation as a sign of disinterest. My schedule has been very busy. Still, I am reviewing the literature on cave bears for possible contribution. The following Grandal-d’Anglade article offers some interesting insight into cave bear ancestry. In the near future, I plan to summarize the key points. Abstract: In this contribution a morphometric study of the lower carnassial of the Cave Bear ( Ursus deningeri and Ursus spelaeus) from several populations of diverse European localities and also different ages is carried out. This study includes a morphological analysis of the deployment of dental cusps and metric comparisons focused on general size and convergence of the cusps. The morphologic study (by cluster analysis) presents a grouping trend of the populations according to their geographic position first, then to the chronology. This indicates that the expansion of the cave bear happened at a very early time, and that later did not exist great migratory movements that returned to put in contact remote populations. As for the metric analysis, differences in the degree of convergence of the cusps in the talonid and trigonid are only observed between the oldest sites (more convergent, smaller occlusal surface) and the modern ones (less convergent, larger occlusal surface) independently of their geographic location. Grandal-d’Anglade, A. & López-González, F. 2004. A study of the evolution of the Pleistocene cave bear by morphometric analysis of the lower carnassial. Oryctos 5, 83–94. To be continued....
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Post by grrraaahhh on Mar 6, 2013 17:36:44 GMT -9
@ duanmianxiong & @ divingwolf, this is a good thread. Please do not see my absence or lack of participation as a sign of disinterest. My schedule has been very busy. Still, I am reviewing the literature on cave bears for possible contribution. The following Grandal-d’Anglade article offers some interesting insight into cave bear ancestry. In the near future, I plan to summarize the key points. Abstract: In this contribution a morphometric study of the lower carnassial of the Cave Bear ( Ursus deningeri and Ursus spelaeus) from several populations of diverse European localities and also different ages is carried out. This study includes a morphological analysis of the deployment of dental cusps and metric comparisons focused on general size and convergence of the cusps. The morphologic study (by cluster analysis) presents a grouping trend of the populations according to their geographic position first, then to the chronology. This indicates that the expansion of the cave bear happened at a very early time, and that later did not exist great migratory movements that returned to put in contact remote populations. As for the metric analysis, differences in the degree of convergence of the cusps in the talonid and trigonid are only observed between the oldest sites (more convergent, smaller occlusal surface) and the modern ones (less convergent, larger occlusal surface) independently of their geographic location. Grandal-d’Anglade, A. & López-González, F. 2004. A study of the evolution of the Pleistocene cave bear by morphometric analysis of the lower carnassial. Oryctos 5, 83–94. To be continued.... Text extract.... The cave bear lineage is formed by two species, U. deningeri VON REICHENAU 1906 and U. spelaeus ROSENMÜLLER 1794, anteceded by a more primitive form, usually named Ursus savini ANDREWS 1922 (Kurtén, 1968), that sometimes is considered as a variety or subspecies of U. deningeri (Kurtén, 1969a; Bishop, 1982; Mazza & Rustioni, 1994). These three species are chronospecies. Unlike biological species, chronospecies are arbitrary divisions of a single evolutionary lineage, defined on the basis of morphological change. According to Simpson (1961) the morphologic differences between species should be at least as large as those between living species of the same taxonomic group. The author's definition of chronospecies is central. For better understanding of chronospecies definition read the following thread, Species: Definition & Concepts.To be continued... P.S. For those interested, a literature milestone in animal taxonomy study. SIMPSON, G.G. 1961. Principles of Animal Taxonomy. New York. Columbia University Press. 247 pp.
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Post by duanmianxiong on Mar 16, 2013 1:32:36 GMT -9
Part of Asian cave bears distribution Attachments:
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Post by duanmianxiong on Mar 16, 2013 1:34:42 GMT -9
source:First DNA sequences from Asian cave bear fossils reveal deep divergences and complex phylogeographic patterns
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Post by duanmianxiong on Mar 16, 2013 1:35:11 GMT -9
Phylogeny Attachments:
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Post by duanmianxiong on Mar 16, 2013 1:56:31 GMT -9
Ursus rossicus is a kind of small cave bears. In:Pleistocene small cave bear (Ursus rossicus) from the South Siberia, Russia author said: "Small cave bear Ursus rossicus Borissiak, 1930 has been widely distributed in Northern Eurasia in the Middle and Late Pleistocene. In East Europe this species was found in the south of Ukraine, Northern Caucasus, Lower Volga River, Bolshoi Irgiz River basin, Ural River and in foothills of Ural Mountains (BORISSIAK, 1932, VERESHCHAGIN 1959, 1982, K U Z M I N A, 1975, BARYSHNIKOV et al., 1991). It is also known from the plain areas of Kazakhstan (KOJAMKULOVA, 1969). Two subspecies were distinguished: U. r. rossicus from Northern Caucasus (Krasnodar), Lower Volga (Kopanovka) and adjacent plains, and U. r. uralensis Vereshchagin, 1973 from Kizel Cave and other cave localities of Middle and South Ural. The geography of fossil findings points out that the small cave bear was mainly a dweller of open herbaceous areas including the steppe ones. It did not evidently penetrate to West Europe where its remains are not recorded." The length of mandible:255.5,267mm,respectively. Is has relative developed P4,resemble that of U.spelaeus.But still with a m1,m2 that resemble U.savini later in :The first record of “spelaeoid” bears in Arctic Siberia(2011) the authors put this spelaeus into U.savini Attachments:
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Post by duanmianxiong on Mar 16, 2013 2:08:15 GMT -9
Finally,there is a good summary of differences between cave bear. source:The first record of “spelaeoid” bears in Arctic Siberia Attachments:
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Post by grrraaahhh on Mar 20, 2013 10:31:46 GMT -9
@ duanmianxiong & @ divingwolf, this is a good thread. Please do not see my absence or lack of participation as a sign of disinterest. My schedule has been very busy. Still, I am reviewing the literature on cave bears for possible contribution. The following Grandal-d’Anglade article offers some interesting insight into cave bear ancestry. In the near future, I plan to summarize the key points. Abstract: In this contribution a morphometric study of the lower carnassial of the Cave Bear ( Ursus deningeri and Ursus spelaeus) from several populations of diverse European localities and also different ages is carried out. This study includes a morphological analysis of the deployment of dental cusps and metric comparisons focused on general size and convergence of the cusps. The morphologic study (by cluster analysis) presents a grouping trend of the populations according to their geographic position first, then to the chronology. This indicates that the expansion of the cave bear happened at a very early time, and that later did not exist great migratory movements that returned to put in contact remote populations. As for the metric analysis, differences in the degree of convergence of the cusps in the talonid and trigonid are only observed between the oldest sites (more convergent, smaller occlusal surface) and the modern ones (less convergent, larger occlusal surface) independently of their geographic location. Grandal-d’Anglade, A. & López-González, F. 2004. A study of the evolution of the Pleistocene cave bear by morphometric analysis of the lower carnassial. Oryctos 5, 83–94. To be continued.... Text extract.... The cave bear lineage is formed by two species, U. deningeri VON REICHENAU 1906 and U. spelaeus ROSENMÜLLER 1794, anteceded by a more primitive form, usually named Ursus savini ANDREWS 1922 (Kurtén, 1968), that sometimes is considered as a variety or subspecies of U. deningeri (Kurtén, 1969a; Bishop, 1982; Mazza & Rustioni, 1994). These three species are chronospecies. Unlike biological species, chronospecies are arbitrary divisions of a single evolutionary lineage, defined on the basis of morphological change. According to Simpson (1961) the morphologic differences between species should be at least as large as those between living species of the same taxonomic group. The author's definition of chronospecies is central. For better understanding of chronospecies definition read the following thread, Species: Definition & Concepts.To be continued... P.S. For those interested, a literature milestone in animal taxonomy study. SIMPSON, G.G. 1961. Principles of Animal Taxonomy. New York. Columbia University Press. 247 pp. Key Paraphrased Points:I. Morphological analysis suggests that after a wide diffusion of the species across Europe at an early time the populations became isolated by diverse geographical barriers and distance. This fact caused a likely parallel evolution and the consequent appearance of geographical types more or less defined. Noticeable differences of chronological origin are not observed in their morphology, but their geographic realm has more importance to establish the similarities and differences between sites. The passage of more primitive forms (U. deningeri) to the more modern ( U. spelaeus) took place gradually and independently in different areas, and therefore it cannot be established chronologically for all Europe in a generalized way. II. Analysis results allow the author to reject a well-defined separation of both species. All the Middle Pleistocene populations here considered (including those subspecies described such as U. spelaeus var. hercynica from Einhornhohle (Rode, 1935), U. deningeri savini from Bacton (Kurtén, 1969a), U, deningeri hund- sheimensis (Zapfe, 1946), Ursus deningeri n. ssp. from Cunturines (Rabeder & Nagel, 2001) show a higher affinity to their geographically closer modem relatives than among them. Also, the grouping does not reflect the differences observed in some Upper Pleistocene sites by several authors that named different subspecies such as U. spelaeus parvilatipedis from Troskaeta (Torres Pérez-Hidalgo et al., 1991), or U. spelaeus odessanus from Odessa (Von Nordmann, 1858). Thus, the morphological differences between the lower carnassial of both species are not well defined. III. According to our results, the lower carnassial of the cave bear has undergone an increase in the size and the occlusal surface throughout the Pleistocene. Concerning the convergence of the cusps, it is possible to affirm that the Middle Pleistocene populations present more convergent cusps than the Upper Pleistocene ones (with the exception of the paraconid). The Convergence indexes here considered could be good indicators of the degree of evolution attained by a population. However we do not think they could be used to differentiate both species, since the sample is scarce and much more populations of intermediate age should be included in order to see if the difference is well defined or not. However, the metric differences observed along the lineage don’t show any discontinuity except the above mentioned of Repolust. With the data collected, the author cannot give a good explanation for this phenomenon, that probably has a parallelism in other cheek teeth and should be investigated with more detail. IV. Taking into account the definition of chronospecies only clear morphological differences between two groups from a single lineage are concluding to establish different species. The stratigraphic position of the bone remains gives not enough evidence to make a separation. V. According to the morphology of the lower carnassial it is not possible, in our opinion, to affirm that U. deningeri and U. spelaeus are different species. Following earlier work in the phylogeny of cave bears, this position is consistent with other notable authors’ Ehrenberg (1928), Erdbrink (1953), Kurtén (1976) and Mazza & Rustioni (1994).
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