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长久以来,指骨弯曲程度都被用来推断化石灵长类移动行为方式.此前已有一些方法被提出并用于定量化比较指骨弯曲程度,包括半径弯曲程度法(radius of curvature)、夹角法(included angle,IA)、标准化矩臂弯曲程度法(normalized curvature moment arm,NCMA)以及高精度多项式曲线拟合法(high-resolution polynomial curve fitting,HR-PCF).然而,在对指骨弯曲程度进行定量化的过程中,这些方法都显示出了理论或技术上的局限性.因此,在运用这些方法之前,应当谨慎考虑其适用性和精确程度对分析结果所产生的影响.鉴于此,为了避免先前方法中存在的问题并更加精确地定量描述指骨弯曲程度,本文介绍了一种新方法作为替代.该方法基于对指骨侧视图背侧轮廓曲线几何形态测量学标志点数据的四阶多项式曲线拟合,称为几何形态测量学—多项式曲线拟合法(4th order polynomial curve fitting on geometric morphometric landmark data,GM-PCF).它以标准化指骨曲线高度(normalized phalangeal curve height,NPCH)作为指骨弯曲程度的定量指标,并且可以将平均标准化指骨曲线进行可视化以用于其弯曲程度的直观对比.此外,它还可以提供在解释指骨弯曲程度的功能意义中非常关键的指骨(背侧轮廓曲线)长度比例信息.GM-PCF还能够分析化石中常见的不完整的指骨.为了检验新方法的适用性,我们从现生类人猿(anthropoids)中选取了15个涵盖灵长类大部分移动行为方式的类群作为参考样本,采用GM-PCF方法对其指骨弯曲程度进行了定量分析,结果表明标准化指骨曲线高度(NPCH)对灵长类移动行为方式有很好的指示意义,配合指骨曲线长度,还可以更进一步了解树栖四足行走(arboreal quadrupedalism)、悬垂(suspension)与摆荡(brachiation)等行为与灵长类体型大小的关系.作为个案,我们采用新方法对中国中新世的两种禄丰古猿(禄丰禄丰古猿Lufengpithecus lufengensis和蝴蝶禄丰古猿Lufengpithecus hudienensis)的指骨弯曲程度与参考样本进行了对比,并根据对比结果对其最为可能的移动行为方式偏好进行了推断.“,”Phalangeal curvature has long been used to infer locomotor behavior in fossil primates.Several methods,such as radius of curvature,included angle (IA),normalized curvature moment arm (NCMA),and high-resolution polynomial curve fitting (HR-PCF),have been employed to quantify and compare phalangeal curvature.However,each method has theoretical or technical limitations in the degree to which they are able to accurately quantify phalangeal curvature,and these undermine the applicability and utility of these methods.A novel method of analyzing phalangeal curvature,based on 4th order polynomial curve fitting on geometric morphometric landmark data (GM-PCF),is described here as an alternative method.GM-PCF avoids the problems with previously employed methods and provides a more accurate representation of phalangeal curvature.It uses normalized phalangeal curve height (NPCH) as a quantitative indicator of phalangeal curvature,and depicts the average normalized phalangeal curve for qualitative comparison of curvature.Furthermore,it provides additional information about phalangeal proportions that are crucial for interpreting the functional relationships of phalangeal curvature.GM-PCF is also capable of dealing with incomplete phalanges.To test the utility of the new method,fifteen groups of extant anthropoid primates are used as a reference sample for comparison with two species of Miocene hominoids from China,Lufengpithecus lufengensis and Lufengpithecus hudienensis.The results of the GM-PCF analysis are used to infer the most likely locomotor behavior of the fossil hominoids.