This photo was taken in 2014.
Fuji Safari Park no longer exhibits warthogs, as well as other zoos in Japan.
It is said that the warthogs are still kept at the zoo off exhibit, but it is not confirmed.
As far as I know, the desert warthog's upper warts point downwards rather than upwards and look bonier, the head structure seems to be different as well. I'm by no means an expert, but this looks like a common warthog as discussed before.
Back then, warthogs were only one species (Phacochoerus aethiopicus) and the common warthog was considered a subspecies, before they were split which is why many zoos signed their warthogs as aethiopicus
