Austrailan Treecreepers (Climacteris spp.)

    These are a group of birds in the genus Climacteris that live in savannahs in Australia. There are a number of savannah woodlands that occur on the continent, which are separated by barriers of desert. The range of each of the tree creeper species or subspecies is in general confined to just of the woodlands, presumably the woodland in which that species evolved to specific status. This inference is based on the assumption that what are recognized as morphologically distinct "species"  are in fact reproductively isolated from each other. At the very least, however, this example illustrates the pattern of genetic divergence in isolation that is postulated to occur in allopatric lineage splitting.
 

   Distribution of different forms of two species in the genus Climacteris (C. picumnus and C. melanura) in Australia.  Hatched and shaded areas indicated major savannah woodland areas, the habitat in which these birds live.  Black arrows indicate barriers to movement.  A distinct form is associated with each savannah area, suggesting that these areas are centers of diversification by allopatric speciation.  This example constitutes distributional evidence supporting the view that allopatric speciation is common in nature.  (From E. Mayr.  1963.  Animal Species and Evoluion.  Belknap Press, Cambridge, MA.)
 
 
 
 
 
 
 
 
 
 
 
 

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