中文摘要：

间齿螺（Metodontia）是我国现生陆生蜗牛的常见属，也是黄土地层中常见的蜗牛化石，汉山间齿螺（Metodontiahuaiensis）和烟台间齿螺（Metodontiayantaiensis）是该属的两个常见种。我国现生间齿螺的地理分布调查取得了丰硕的成果，为间齿螺化石作为夏季风气候变化的代用指标提供了依据，但对现生间齿螺的数量分布和生态因子最适区域，还缺少系统的研究，限制了对间齿螺古生态古气候意义的深入理解。通过对黄土高原及周边地区356个表土蜗牛组合的研究，揭示了间齿螺及其优势种的数量分布与气候参数的关系，以及与经纬度和海拔高度的关系，并利用加权平均方法定量估算了汉山间齿螺和烟台间齿螺的温度和降水量最适范围。结果表明，在我们的研究区域内，含量大于20％的间齿螺，主要分布在年均温大于11℃、年降水量550～850mm的地区，36°N以南、110°E以东的地区，海拔在750m以下的地区；含量低于10％的间齿螺，在年均温5～15℃、年降水量380～700mm的地点都有分布，主要分布在33°～40．5°N、103．7°～117．5°E范围内，海拔在2000m以下的地区；年均温低于5℃、年降水量低于380mm的地区，海拔2000m以上的地区，基本上没有间齿螺生长；汉山间齿螺和烟台间齿螺年均温度最适范围分别为10．2～14．1cC左右和8．9～14．O℃左右（实测值与推导值R2=0．70，推导误差RMSEP=1．99），年降水量最适范围分别为530～800mm左右和470～750mm左右（R=0．81，RMSEP=90．87）。上述结果为间齿螺的古生态古气候研究和物种多样性保护提供了基础生态数据。

英文摘要：

Metodontia genus is among the common modern and fossil land snails in the Chinese Loess Plateau and adjacent regions. Metodontia huaiensis and Metodontia yantaiensis are the two most common species of Metodontia. Up to now, classification and geographical distribution of Metodontia have made significant progress, providing crucial knowledge for using Metodontia taxon as warm and moist species to decipher paleoclimatic changes. However, little is known about quantitative distribution and ecological amplitude of Metodontia, which makes it almost impossible to understand deeply or quantitatively paleoclimatic changes recorded by Metodontia. Here, land snail assemblages are collected from surface soil samples at 356 sites covering the Loess Plateau and adjacent regions, ranging in latitude from 29.75°N to 43.70°N and in longitude from 98.23°E to 120.34°E. Modern climatic data of the sampling sites are obtained by spatial interpolation on the 40-year averaged meteorological data from a database consisting of more than 700 meteorological stations that is maintained by the China Meteorological Administration （CMA）. Four climate parameters are chosen. Mean annual temperature （MAT） of the studied region spans from ca.l.2°C to 16.4°C , mean annual precipitation （MAP） from ca.210mm to 1630mm, July average temperature from ca.12.8°C to 28.0°C , and July precipitation from ca.45mm to 233mm. In this paper, quantitative distributions of the dominant species of Metodontia and their relations to climate, latitude, longitude and altitude are reported and the optimum ranges of MAT, MAP, July average temperature and July precipitation for Metodontia huaiensis and Metodontia yantaiensis are quantitatively reconstructed using 4 weighted averaging （WA） models, including an inverse-deshrinking WA model, a classical-deshrinking WA model, an inverse-deshrinking tolerance downweighted WA model and a classical-deshrinking tolerance downweighted WA model. Results show that among all the 356 samples, 13 samples do no