Whether to consider the Iriomote Cats & Tsushima Cats to be island species in their own right, or subspecies one of the other, or either or both subspecies of the Leopard Cat, depends largely on which authority you consult. I personally think that the Iriomote Cat is distinct enough to be considered a separate (albeit closely related) species. From what I have seen and read of the Tsushima Cats, they appear to be an distinct island subspecies of Leopard Cat.

In recent years there has been a tendency among taxonomists to be “lumpers”, relegating a lot of animals formerly thought of as separate species to subspecies status and greatly reducing the number of generally accepted subspecies as well. I think that we are seeing some degree of reversal in this trend. Especially as the technology to decode DNA becomes ever more precise, I think that more cats will be recognized as distinct subspecies or even species.

Many think that the Tsushima cat is merely a variant of the Manchurian or Eastern subspecies of leopard cat, but I tend to think there could be enough there to make it a separate subspecies. It might seem like nitpicking or an unimportant distinction to some, but for the cats themselves, recognition as a species or sub-species can be very important as it can alter their conservation status.

Anyway, like I said, taxonomy can be tricky and the discussion is likely to continue.

The same kind of taxonomy difficulty can be seen with the Tsushima cat. Unlike the Iriomote cat (which is seen more by some to be a separate species) the Tsushima cat is definitely considered to be a subspecies of leopard cat, yet there is still dispute as to how to classify it. Some say the Tsushima cat is the same as the manchurian subspecies of leopard cat, but not everyone agrees. In fact, many sources you will see list this cat as Prionailurus bengalensis euptilura, saying that it is more or less the same as the Eastern Siberian Amur leopard cat. Still others list it as its own subspecies and label it Prionailurus bengalensis tsushimansis. Taxonomy can be a confusing thing and it is very much so with cats.

The only points that seem to be agreed upon with the classification of the Tsushima cat is that
1) It is different from the Iriomote cat
and
2) it is a subspecies of leopard cat.

seriously, though, thanks for the update! i’ve learned more about existing animals once thought mythic or ‘folklore’ since participating in this forum than i have reading SCIENTIFIC AMERICAN for a dozen years!

keep up the good work, everyone! much appreciated here!