科研之友
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摘要
Lengths of hind claw, tarsus, bill, wing and tail plus bill depth and width, wing tip and tail graduation were measured in nearly 2,000 specimens from all nine currently accepted Certhia species and most subspecies to provide morphometric characterisation. In a discriminant analysis for all species, only C. [discolor], C. nipalensis and C. tianquanensis were clearly separated from each other and from the remaining set of five species. Nevertheless, a cluster analysis produced dendrograms approximating the current molecular phylogeny of the genus. Thus, there is an overall relatively low morphometric diversity among Certhia treecreepers. Recently split allospecies can only partly be distinguished: the disjunct C. [discolor] taxa exhibit no clear affiliation to either allospecies, C. discolor or C. manipurensis, while in C. [familiaris] the species split is corroborated on one hand by a break in geographic trends and on the other by clear separability of neighbouring heterospecific populations. Also, in areas of sympatry, Certhia species differ markedly in body measurements related to the peculiar adaptations of treecreepers to their habitat (tree bark): i.e. bill, claw and tail measurements. The same applies to sexual dimorphism: males, on average larger in all body measurements, have, in particular, longer bills, possibly in order to better exploit the limited food and partition it between the two sexes.
- 出版日期2009-4
