本研究旨在利用先进的 3D 形态几何技术描述舞熊 Belitsa 公园的棕熊 (U. arctos) 的头骨和下颌骨。目的是利用先进的 3D 几何形态测量方法探索性别二态性和大小如何影响颅骨结构。使用了 12 只棕熊的头骨和下颌骨的三维模型。本研究观察了雄性和雌性棕熊头骨形态的差异。雄性棕熊的头骨比雌性棕熊的头骨大,颈项区域上部向后方的延伸更为明显。此外,与雌性棕熊相比,雄性棕熊的额叶后部显得明显更薄。对下颌骨的分析显示,男性的咬肌窝比女性更发达。研究发现,男性和女性之间的这些形状差异受到体型的影响。统计分析表明,体型大小对头骨 PC1 值存在显着的异速生长效应,这表明巨熊的头骨往往更长。这意味着体型较大的个体表现出更大的颅骨伸长。相比之下,下颌骨 PC1 值没有显示出与尺寸相关的变化,表明下颌形状受整体尺寸的影响较小。然而,下颌骨中的 PC2 值随着样本的增大而显着增加,表明较大的熊有更大的咬肌窝。这种形态适应可能会提高较大个体的摄食效率和咬合强度,反映了棕熊下颌形态的功能适应。 这些发现有助于我们了解棕熊的性别二态性和与体型相关的形态适应,为了解它们在栖息地中的适应生物学和生态作用提供了见解。
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Morpho-Geometric Description of the Skulls and Mandibles of Brown Bears (Ursus arctos) from the Dancing Bear Belitsa Park
The present study aimed to describe the skull and mandibles of the brown bear (U. arctos) from the Dancing Bear Belitsa Park using advanced 3D morpho-geometric techniques. The objective was to explore how sexual dimorphism and size influence cranial structures using advanced 3D geometric morphometric methods. Three-dimensional models of the skulls and mandibles of 12 brown bears were used. Differences in skull morphology between male and female brown bears were observed in this study. The male brown bear skull, larger than the female, exhibited a more pronounced extension of the upper part of the nuchal region towards the posterior. Additionally, the posterior part of the frontal region appeared notably thinner in male brown bears compared to females. Analysis of the mandible revealed that the masseteric fossa was more developed in males than females. These shape differences between males and females were found to be influenced by body size. Statistical analyses indicated a significant allometric effect of body size on skull PC1 values, suggesting that giant bears tend to have more elongated skulls. This implies a relationship in which larger individuals exhibit greater cranial elongation. In contrast, mandible PC1 values showed no size-related variation, indicating that mandibular shape is less influenced by overall body size. However, PC2 values in the mandible increased significantly with larger specimens, indicating a larger masseteric fossa in larger bears. This morphological adaptation potentially enhances feeding efficiency and bite strength in larger individuals, reflecting functional adaptations in brown-bear mandibular morphology. These findings contribute to our understanding of sexual dimorphism and size-related morphological adaptations in brown bears, providing insights into their adaptation biology and ecological roles within their habitats.