Biogeography of rotifers etc

[GreenLarry]

Looking at the excellent pics on this and other sites, I came to notice how many seem very similar if not the same as species I have seen under my microscope.
I live in Engand and the majority of the members are from the USA , plus a few Europenas and yet they show species that look identical to what I've seen, and Ive never been abroad.

Some even have latin names which i recognise-it just amazes me how no matter where one goes we se the same species!
Imagine if that were the case with higher animals, there'd be Crocodiles in Cork,Elephants in Eukraine, and Three Toed Sloths in Tucson!
(Of corse in prehistoric times, they probably were!)