Fig leaves are very variable from species to species. This is helpful in trying to identify a fig as belonging to a certain species. The problem is that the leaves on even a single plant can show great variation depending upon cultural conditions of light, moisture, growth in a container, wind, etc.
As an example the shot below shows several leaves removed from a single Ficus plant. The variability would make an attemp at a scientific identification very difficult. Many factors must be used to help in correctly identifying a fig. These include the leaf, bark, syconia, stipules etc.
Figs are wonderful plants to use for bonsai but they can infuriating to correctly identify without figs/syconia.