Oncilla mates with Geoffroy’s cat and mated with the pampas cat
The oncilla in the south of Brazil currently mates with Geoffroy’s cat (L. geoffroyi) creating a hybrid, while the oncilla in the northeast of Brazil in ancient times mated with the pampas cat (L. colocolo)¹. Currently there is a relatively small overlap in the distributions of the oncilla and Geoffroy’s cat. The southern oncillas don’t mix with the northern ones and for this reason it is said that there should be two species of oncilla.

Tigrina mates with Geoffroy’s cat
Also, the hybrid offspring mate with the original “purebred” species that created them. This is backcrossing and is called “introgression”. So, for example the offspring of an oncilla and Geoffroy’s cat might mate with a Geoffroy’s cat.
This is interesting because one of the criticisms of captive tigers is that they are often “generic” meaning they are neither Siberian tigers nor Bengal tigers. They are not purebred. Well, we can now say that a lot of oncillas in the wild are not purebred either. The same can be said of the Scottish wildcat, which mates with local feral and stray domestic cats creating the “Kellas Cat” a hybrid. There are quite possibly no purebred Scottish wildcats left.
So, is a “purebred” wild cat species important? No, seems to be the answer. It is natural for some species of the same genus (a group of species that are similar) to mate with each. It probably improves the species. It certainly should help offset problems of inbreeding if the population is isolated or small.
The scientific name for the oncilla is Leopardus tigrinus. The name oncilla is often used but there are many other names, confusingly, and the one used in the latest study that revealed this large scale hybridization is “tigrina”.
I am surprised that the experts have suggested that because the tigrinas in the south don’t mate with the tigrinas in the north that they should be considered different species. I have seen no information to suggest that they are different at the DNA level. Perhaps I have missed something.
Note: (1) Current Biology.