辽西中生代鸟类跗跖骨测量数据的统计分析及意义

跗跖骨是鸟类后肢骨骼的重要组成之一,其形态特征对恢复鸟类的行为和习性具有重要的指示意义。本文以鸟类的跗跖骨为研究对象,共观察了200余例有代表性的现生鸟类标本,并对其中15个目中的154例标本进行了多组数据的测量。还将跗跖骨各形态特征进行量化分析研究,引入相关分析和因子分析等统计分析方法。对现生鸟类跗跖骨5组(12个)变量进行分析,研究各变量间的相关程度,对变量进行主成分分析,提取出2个主成分,其中第1主成分包括第Ⅱ,Ⅲ,Ⅳ三个跖骨的宽度变量；第2主成分包括第Ⅱ跖骨滑车相对于第Ⅲ跖骨滑车的上下及前后位置两变量,以及第Ⅳ跖骨滑车相对于第Ⅲ跖骨滑车的前后位置变量。对这6个变量的分析表明,它们对于区别鸟类的栖息习性具有显著的指示作用。通过对在中国(辽西为主)已发现的25例中生代鸟类跗跖骨远端4个变量的统计分析,表明它们同样具有区别树栖和地栖鸟类的显著意义,而且分析的结果与参考鸟类其他特征(如爪的形态、脚趾的比例等)所得出的结论基本一致。

STATISTIC ANALYSIS OF THE TARSOMETATARSUS MORPHOLOGY OF MESOZOIC BIRDS FROM WESTERN LIAONING,CHINA AND ITS IMPLICATIONS

The tarsometatarsus is an important component of the avian hindlimb.It is well known that the morphology of avian tarsometatarsus is a useful indicator of the locomotion and habit of a bird.This paper focuses on the morphology of the distal tarsometatarsus of birds.The tarso- metatarsi of 154 specimens of living birds belonging to 15 orders were measured although over 200 specimens were examined.Statistic analysis of the morphology of the distal tarsometatarsus of extant birds was conducted.Correlation analysis and factor analysis indicated that two princi- pal components were derived with each comprising 3 variables.The first principal component include the width of metatarsal trochleaⅡ,ⅢandⅥ;and the second principal component in- cludes the relative height and anterior projection of metatarsal trochleaⅡcompared to that ofⅢ,and relative anterior projection of metatarsal trochleaⅥcompared to that ofⅢ.Statistic analysis of these 6 variables showed that they could be used to well distinguish arboreal and ter- restrial birds.In this paper,4 variables of the distal tarsometatarsus were also collected from 25 specimens of fossil birds belonging to 14 genera of Early Cretaceous birds from Western Liaoning in China.Analyses of these variables have also proven to be useful in distinguishing arboreal and terrestrial birds,and the result is generally consistent with a conclusion reached on the basis of other analysis,i.e.those based on the claw geometry and toe proportion.