It is strange that biologists can’t seem to deal with this and what it suggests: the non-random process of evolution and the form factor behind it.
The more we look, the more we find. Structures such as jaws, teeth, ears, fins, legs, and wings all keep evolving independently in animals.
Source: Crabs Have Evolved Five Separate Times—Why Do the Same Forms Keep Appearing in Nature?
1848+: The End(s) of History 