A really good summary of the find of dwarf human remains on the island of Flores in Indonesia can be found at the Loom . These remains are scarcely 20,000 years old, suggesting persistent survival of multiple non-human hominids until right up to the edge of human history. (Neandertals were in the south of Spain until about 30,000 years ago.) This is completely wild, and suggests that Tolkein's Lord of the Rings was a documentary. Who knew?
The brain case of the skeleton is also very tiny, which might mean that they were less intelligent overall. However, present-day (normal sized) humans with hydrocephalus or even following surgical hemispherectomies (in both cases lacking quite a lot of brain material) are actually pretty capable people. Not to oversimplify, but software as well as hardware seems to be a part of the human intelligence package. Moreover, there were tools associated with the site, of the sort made by homo erectus.
Dwarfism in these humans may have been an adaptation to scarce resources on the island. In the same bed of bones there were dwarf elephant remains. Oh, and a little gold ring.