中文摘要：

腕足动物系统古生物研究中,对特征相近的两个分子的比较通常定性且直观,较少进行定量统计分析。判别分析是一种重要的分类分析方法,也是动植物分类的主要统计学基础。劣扭月贝属（Katastrophomena）与扭月贝属（Strophomena）虽分别归于扭月贝科的两个亚科,但它们的特征却很相似,对它们的属征差异各家观点不一致。经过对国内外文献中归于Katastrophomena与Strophomena两属共计31种（其中3个亚种,3个未定种）52个标本（其中7个正型,23个副型,6个亚型,4个选型）进行统计学上的判别分析,建立判别方程并证明其有效性,将两属定量地区分开来,较为科学地明确了它们的属征差异,确证了Katastrophomena属的分类地位。对K.（Costistrophomena）与K.（Katastrophomena）两个亚属的壳线频率进行统计分析,认为两者不存在本质差异,建议将它们合并。

英文摘要：

In traditional systematic paleontology of brachiopods,methods of comparison for two similar genera are usually qualitative and intuitive rather than quantitative.Discriminant Analysis（DA）is an important technique of classification analysis,and forms a statistical basis for the taxonomy of modern biology,but the method drew less attention in paleontology.The two genera of Strophomenidae,Katastrophomena and Strohpomena have been assigned to Furcitellinae and Strophomeninae respectively.But,the characters of these two ge-nera are so close that there exist many different opinions on their taxonomic assignments.In order to differentiate these two genera quantitatively,31 species assigned to Katastrophomena and Stropho-mena are examined.There are 52 specimens（including 7 holotypes,23 paratypes,6 hypotypes,and 4 lectotypes）being compared.Having mea-sured the known specimens in length and width of the valves and the ventral muscle fields,the analysis of covariance is herein performed.The result shows a significant difference between Katastropho-mena and Strophomena which is represented by length ratio of ventral valve and muscle field.The discriminant function is built through the DA processed and its validity is tested.The significant validity of the function indicates that it can be used to differentiate Katastrophomena from Strophomena.