Cordylodus　proavus-Cordylodus　lindstromi的线系进化  

THE PHYLETIC EVOLUTION FROM CORDYLODUS PROAVUS TO CORDYLODUS LINDSTROMI

作　　者：赵达[1,2] 吴水忠[1,2] 

机构地区：[1]长春地质学院地球科学系 [2]东北大学秦皇岛分校

出　　处：《长春地质学院学报》1997年第1期7-11,共5页

摘　　要：Ｃｏｒｄｙｌｏｄｕｓｌｉｎｄｓｔｒｏｍｉ不是从Ｃｏｒｄｙｌｏｄｕｓｉｎｔｅｒｍｅｄｉｕｓ进化而来，也不是从Ｃｏｒｄｙ－ｌｏｄｕｓｃａｂｏｔｉ演化来的，而是从Ｃｏｒｄｙｌｏｄｕｓｐｒｏａｖｕｓ直接进化的，中间经过两次突变Ｃ．ｐｒｏａｖｕｓｄｅｆｏｒｍｉｓｎ．ｓｕｂｓｐ．和Ｃ．ｐｒｏａｖｕｓａｍｂｉｇｕｕｓｎ．ｓｕｂｓｐ．，而达到Ｃ．ｐｒｏｌｉｎｄｓｔｒｏｍｉ，再由此而演化成Ｃ．ｌｉｎｄｓｔｒｏｍｉ。上述过程是在同一海侵期内，同一地区连续发生的线系进化。由此可见，标志奥陶系底界的Ｃ．Cordylodus lindstromi has evolved neither from Cordylodus intermedius nor from Cordylodus caboti . It has evolved from Cordylodus prolindstromi which has evolved from Cordylodus proavus through two times of mutation of the Cordylodus proavus . They have evolved without the separation of palaeogeography, therefore, this is a phyletic evolution and the evolutive system is shown in figure 1. The process had been finished during a synchronous transgression and the facts suggest a difference of the time between the beginning transgression of Ordovician and the first occurrence of the Cordylocus lindstromi .

关 键 词：林氏肿牙形石 线系进化 牙形石 奥陶纪 

分 类 号：Q915.642[天文地球—古生物学与地层学] Q915.81[生物学—古生物学]