The plateau zokor (Eospalax baileyi) is employed as an ideal model for examining the relationships between phenotypic and ecological adaptations to the underground conditions in which the skull morphology evolves to adapt to tunnel environment. We evaluated the influence of environmental factors (altitude, temperature, and precipitation) and geographical distance on the variations in skull morphology of a native subterranean rodent plateau zokor population. Thin-plate spline showed that the trend of morphological changes along the CV1 axis was as follows: the two zygomatic arch and the two postorbital processes moved down, the two mastoid processes and the tooth row moved upward, and the tympanic bulla grew longer. The changes along the CV2 axis were as follows: the nasal bone and the tooth row became longer, the distance between the two anterior tips of zygomatic arch lengthened, the infraorbital foramen became smaller, the whole posterior part of the skull became shorter, the zygomatic bone and the two posterior tips of zygomatic arch moved down, and the foramen magnum became bigger. Thus we found significant differences in the skull shape among the seven populations studied. Along with the reduction in the altitude and increase in the mean annual temperature and mean annual precipitation, the nasal bone became shorter, the distance between the two anterior tips of the zygomatic arch became shorter, the whole posterior part of the skull lengthened, the infraorbital foramen became smaller, the two mastoid processes moved upward, and the occipital bone moved down on the dorsal surface of the skull. On the ventral surface of the skull, with an increase in the altitude, mean annual temperature, and mean annual precipitation, the tympanic bulla became shorter, the tooth row moved down, and the foramen magnum became smaller. The morphological changes in the skull were significantly positively correlated with environmental factors. Finally, there was a significant positive correlation between the Procrustes distance matrix of the skull and the geographic distance matrix, which indicates that the evolution of the plateau zokor follows the distance isolation model, but it needs to be further explored from genetic perspectives.

中文翻译：

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高原zokor（Eospalax Baieyi）的几何形态测量分析揭示了环境因素对头骨变化的显着影响

高原 zokor (Eospalax Baieyi) 被用作检查表型和生态适应对地下条件之间关系的理想模型，在这些条件下，头骨形态演变以适应隧道环境。我们评估了环境因素（海拔、温度和降水）和地理距离对原生地下啮齿动物高原 zokor 种群头骨形态变化的影响。薄板样条显示沿CV1轴的形态变化趋势为：两颧弓和两眶后突下移，两乳突和牙列上移，鼓泡变长。沿CV2轴的变化如下：鼻骨和牙列变长，颧弓两前尖间距变长，眶下孔变小，整个颅骨后部变短，颧骨及颧弓两后尖下移，枕骨大孔变大。因此，我们发现所研究的七个种群的头骨形状存在显着差异。随着海拔的降低，年平均气温和年平均降水量的增加，鼻骨变短，颧弓两前尖之间的距离变短，整个颅骨后部变长，眶下骨孔变小，两个乳突向上移动，枕骨在颅骨背面向下移动。在头骨的腹面，随着海拔高度、年平均气温和年平均降水量的增加，鼓泡变短，牙列下移，枕骨大孔变小。颅骨的形态变化与环境因素呈显着正相关。最后，头骨的Procrustes距离矩阵与地理距离矩阵之间存在显着的正相关，表明高原鲢的演化遵循距离隔离模型，但需要从遗传学角度进一步探讨。颅骨的形态变化与环境因素呈显着正相关。最后，头骨的Procrustes距离矩阵与地理距离矩阵之间存在显着的正相关，表明高原鲢的演化遵循距离隔离模型，但需要从遗传学角度进一步探讨。颅骨的形态变化与环境因素呈显着正相关。最后，头骨的Procrustes距离矩阵与地理距离矩阵之间存在显着的正相关，表明高原鲢的演化遵循距离隔离模型，但需要从遗传学角度进一步探讨。