•      Spiders have no wings, they are comparatively small animals and their ability to migrate is very restricted. This is why, we suppose they inhabit the same (or almost the same) territory where they first time appeared. In this map you can see geographic distribution of Intruda signata – very common ground spider from Australia. By triangles and squares marked findings of some new species from the same genus. Total picture let us think that homeland of all these spiders is Australia.

For some very close each-other groups we have very interesting distribution like this. Here you can see two close relative genera Callilepis and Eilica. You can see that when one genus – Callilepis – is distributed exclusively in the Northern hemisphere, the other – Eilica – exclusively in Southern one. But if we remember the Continental Drift theory, everything get its simple explanation.

It becomes clear that these two close relatives were separated at a time when pra-mother of all continents – Pangaea – spliced into two mega-continents (that later also were broken down). This diagram helps us understand also why most of the Australian spider species were never found in New Zealand and vice versa, like on the next maps.

This is distribution of spiders genus Anzacia that is very common in Australia, but never in New Zealand.

And this is a distribution of New Zealand spiders of genus Matua.

Google map, GIS, ArcCIS, Gazeter – are invaluable tools in such kind studies. Google map also let us to do analysis of our data on the background of additional information such as continental movement, century climate trends, and much other, which help us to draw conclusions about origin, evolution, and effect of different factors on life (in my case – ground spiders).