几种银杏类叶部化石的计算机分类

CLASSIFICATION OF SOME FOSSIL GINKGOLEAN LEAVES BY COMPUTERIZATION

本文描述了银杏类叶部四种印痕化石:Ginkgo digitara(Brongn.)Heer、Ginkgo huttoni(Sternb.) Heer、Ginkgoites sibiricus(Heer)Seward和 Ginkgoites taeniatus(Braun)Ha-rris。在常规描述的基础上,应用电子计算机技术,试图将定性研究引伸为定量研究。为此,选用了多类判别分析方法进行化石的归类。统计的参数为裂片数目、裂片长度、裂片宽度、叶脉数目和外侧裂片夹角等五项。根据这一方法建立的四个种的判别方程,用各种模式标本或国内外同种标本的参数分别代入,结果恰归该种。本文采用FORTRAN 77算法语言编制源程序,在IBM-PC机上进行计算。

Based on the description of the four species of fossil impressions of ginkgolean leaves, Ginkgo digitata (Brongn.) Heer, Ginkgo huttoni (Sternb.) Heer, Ginkgoites sibiricus (Heer) Seward and Ginkgoites taeniatus (Braun) Harris, the authors attempted to expand the qualita- tive study of their characteristics to quantitative study by means of computerization. The dis- criminant analysis was applied to the classification of these fossil. The statistic variates selected were the lobe number, length, and width, and the nerve number and the angle between two outer lobes. The discriminant equations of the four species established by the analysis were su- bstituted, respectively, with the variates of the type specimens as well as the Chinese or the foreign specimens of the same species. The results correspouded well with species classifica- tion The source programme was designed in the FORTRAN 77 algorithmic language and the calculation was done on the IBM-PC computer.