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GEOGRAPHICAL VARIATIONS OF POSTCRANIAL SKELETON AMONG THE POPULATIONS OF NEOPHOCAENA IN CHINESE WATERS

GAO Anli,ZHOU Kaiya   

  • Online:2006-07-29 Published:2008-07-07

中国水域江豚颅后骨骼的地理变异

高安利,周开亚   

  1. 南京师范大学生物系,南京

Abstract: Geographical variations of postcranial skeleton among the Yangtze,Yellow Sea and South China Sea populations of the finless porpoise,Neophocaena phocaenoides,in Chinese waters were studied with t-test,covariance analysis (Table 2)and stepwise discriminant analysis(Table 3,Fig.2)using 42 measurements based on 142 specimens of all ages (38 from the Yangtze population,59 from the Yellow Sea population and 45 from the South China Sea population)collected in 1974 to 1991 by the Cetacean Research Laboratory,Nanjing Normal University.The results showed that:(1)Geographical variations in the postcranial skeleton among the three Chinese populations were demonstrated in all the ages even for the neonates(Table 2,Fig.2).But the differences were interpreted by a group of variances.No single difference could be used as diagnostic character for subspecies identification.(2) Summary of the results of the comparison among the populations(Table 2 and 4)demonstrated that,the postcranial skeleton in the South China Se a population was the most developed,that of the Yangtze population was the next,and that of the Yellow Sea population was the lowest.(3)Differences between the South China Sea and Yangtze populations were larger than that between the South China Sea and Yellow Sea populations,and therefore were the largest(Table 2,Fig.2).This is in agree with the result determined by external and skull measurements.(4)The degree of the difference and overlap in the measurements among different geographical populations implies that the adaptationary changes of the skull took place slower than those of the external morphology during the evolution of the finless porpoise populations,and those of the postcranlal skeleton,in turn,slower than those of the skull.

Key words: Neophocaena, Population, Postcranlal skeleton, Geographical variation

摘要: 本文根据142号各年龄段的江豚颅后骨骼标奉(其中长江种群标本38号,黄海种群标本59号,南海种群标本45号),选用42项颅后骨骼变量,应用t-检验、协方差分析和判别分析,研究了颅后骨骼在各地理种群之间的变异。结果表明,(1)中国水域江豚不同种群之间在颅后骨骼上的差异是明的,而且表现在包括初生幼体在内的所有年龄段的标本中。0)南海种群的颅后骨骼最发达,长江次之,黄海种群的最不发达。(3)黄海种群与长江种群的差异较小,与南海种群的差异较大;南海种群与长江种群的差异相对最大。(4)颅骨发生的适应性变化比其外形的变化要慢,而颅后骨骼的变化比颅骨的变化还要慢.

关键词: 江豚, 种群, 颅后骨骼, 地理变异