which could be attributed to the fundamental differences
between the two hemispheres in the distribution of oceans and
landmasses. They also inferred that the complex patterns of migration
and range shifts during climatic cycles in the Neogene could
have led to elevated rates of speciation and extinction and resulted
in the abundance of recent divergence in northern clades, whereas
the scattered persistence of mild, wetter habitats in the Southern
Hemisphere might have favored the survival of older lineages