The variability of lower 6776 cheek teeth of spelaeoid (Ursus spelaeus, U. kanivetz, U. deningeri, U. kudarensis, U. savini and U. rossicus) and arctoid lineages (extant and extinct U. arctos) recovered from 176 palaeontological localities was analysed by methods of univariate and multivariate statistics. For comparison, teeth of U. minimus and U. etruscus species, which are ancestral taxa for cave bears and brown bear, were studied. The performed analyses indicate great variability of tooth crown in lower cheek teeth; no distinct general trend was identified in the changes, except for an increase in p4 roundness and in m3 size from U. minimus to big cave bears. Centroids of U. minimus and U. etruscus are at a great distance from those of cave bears; U. arctos occupies an intermediate position between the two groups. Molar characteristics in general are close in U. savini and U. rossicus. The bear species are differentiated in the morphospaces by morphometric variations in the lower cheek teeth but less markedly than in the morphospaces of the upper cheek teeth. A test of the inhibitory developmental cascade model showed that a linear relationship between lower molar dimensions became clear only after premolar p4 was included in the model. Evolutionary trends were found in the tooth changes with time (differently expressed in individual species and in different teeth) depending on environments, in particular on the elevation of the locality above the sea level. The allometric pattern differentiation does not always coincide with phylogenetic relationships between taxa, being most often revealed at the subspecies level. There is a dominant covariance between the upper and lower rows of teeth in accordance with the occlusion scheme. It may vary in manifestation depending on the particular species.

中文翻译：

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穴居熊（食肉动物，s科）下颊齿的形态及对牙列变异性的一般性评论

spelaeoid的下部6776个齿颊（的可变性洞熊，U. kanivetz，U. deningeri，U. kudarensis，U.萨维尼和U. rossicus）和arctoid谱系（现存和灭绝U.棕熊）从176个古生物地方回收是通过单变量和多变量统计方法进行分析。为了比较，U的齿。 按蚊和U. etruscus研究了北极熊和棕熊的祖先分类群。进行的分析表明下颊牙的牙冠变化很大。除了p4圆度的增加和m3大小的增加（从微型小to虫到大型洞穴熊）外，没有发现任何明显的总体趋势。微型小and和小乌龟的质心与洞熊的质心相距很远。U. arctos在两组之间处于中间位置。一般摩尔特点是接近U.萨维尼和U. rossicus。熊的种类在下颌牙齿的形态学差异中在形态空间上有所区别，但不如上颊颊牙齿的形态空间明显。抑制性发展级联模型的测试表明，只有在模型中包括前磨牙p4之后，较低摩尔尺寸之间的线性关系才变得清楚。发现牙齿随时间变化的进化趋势（在不同物种中和不同牙齿中表达不同）取决于环境，特别是根据海拔高度的升高。异速生长模式的差异并不总是与分类群之间的系统发生关系一致，这在亚种水平上最为常见。根据咬合方案，上排和下排牙齿之间存在显着的协方差。