Badak Tanggiling/Scaled Rhinoceros

The Badak Tanggiling is a cryptid sighted in Sumatra, Indonesia. They are described as hoofed mammals similar to the rhinoceros, but with only one horn. They measure ten feet long, and the females are sometimes hornless. A Hunter named J.. C. Hazewinkel supposedly shot eight of these in the 1920s. Some theorize a Javan rhino with a single form may have persisted in Sumatra during this time, leading to these sightings. Currently, Sumatra only has one species of rhino which has two horns. 

Citations:

Eberhart, George M.. Mysterious Creatures [2 Volumes]: A Guide to Cryptozoology [2 Volumes]. Ukraine, Bloomsbury Publishing, 2002.