Albrecht Gene H, Jenkins Paulina D, Godfrey Laurie R
Department of Anatomy and Cell Biology, University of Southern California, Los Angeles, California.
Department of Zoology, British Museum (Natural History), London.
Am J Primatol. 1990;22(1):1-50. doi: 10.1002/ajp.1350220102.
The living Malagasy prosimians and their recently extinct subfossil relatives include about 20 genera and 8 families that can be considered one contemporenous fauna. They exhibit morphological, behavioral, and ecological differences comparable to living anthropoid primates. This diversity is matched by the equally varied topography, climate, and vegetation of Madagascar. To investigate habitat-related size variation, skull lengths of wild-caught adults were used to compare sizes of closely-related conspecific and congeneric "sister taxa." More than 1,550 museum specimens were examined representing virtually all known forms of extant and subfossil Malagasy prosimians. A total of 98 pairwise, sister-taxa comparisons among 76 different taxa from six broadly defined ecogeographic regions revealed a consistent pattern of size variation: (1) the smallest Malagasy prosimians inhabit the semiarid forests, bush, and thickets of the South; (2) next largest are those from the dry deciduous forests of the West and the humid but seasonal forests of the Sambirano; (3) larger yet are those from humid tropical and secondary forests of the East; and (4) the largest of all are the extinct forms of the central highlands that lived in what was probably a savanna-bush-woodland mosaic in the past but is now grasslands devoid of living prosimians. Taxa from the extreme North are more variable in size (small, intermediate, or large), which may reflect the mixture of local habitats in northern Madagascar. The ecogeographic size differences may be adaptive responses related to the carrying capacity of local environments such that smaller-sized species are favoured where the resources they exploit are more limited. Field observations on behavioral thermoregulation, home range size, and population densities offer some support for this hypothesis. Ecologically induced size differences among local populations were probably one factor in speciation events leading to the modern diversity of the Malagasy primates.
现存的马达加斯加原猴类及其最近灭绝的亚化石近亲包括约20个属和8个科，可被视为一个同期动物群。它们在形态、行为和生态上的差异与现存的类人猿灵长类动物相当。马达加斯加同样多样的地形、气候和植被与这种多样性相匹配。为了研究与栖息地相关的体型差异，使用野生捕获的成年个体的头骨长度来比较亲缘关系密切的同种和同属“姐妹分类群”的大小。检查了超过1550个博物馆标本，这些标本几乎代表了所有已知的现存和亚化石马达加斯加原猴类的形式。在来自六个大致定义的生态地理区域的76个不同分类群之间，总共进行了98对姐妹分类群比较，揭示了一种一致的体型差异模式：（1）最小的马达加斯加原猴类栖息在南部的半干旱森林、灌木丛和矮树丛中；（2）其次大的是来自西部干燥落叶林和桑比拉诺湿润但季节性森林的原猴类；（3）更大的是来自东部湿润热带森林和次生林的原猴类；（4）最大的是中部高地已灭绝的原猴类，它们过去生活在可能是稀树草原-灌木丛-林地镶嵌的环境中，但现在是没有现存原猴类的草原。来自最北部的分类群在体型上更具变异性（小、中等或大），这可能反映了马达加斯加北部当地栖息地的混合情况。生态地理上的体型差异可能是与当地环境承载能力相关的适应性反应，使得在它们所利用的资源更有限的地方，体型较小的物种更受青睐。关于行为体温调节、活动范围大小和种群密度的实地观察为这一假设提供了一些支持。当地种群之间由生态因素导致的体型差异可能是导致马达加斯加灵长类动物现代多样性的物种形成事件中的一个因素。
