Jokes aside, an idea has been curdling in my mind for a few days now, when I commented elsewhere on Tolkien's influence on the presence of fantasy orcs. Someone had pointed out that modern fantasy orcs bear little resemblance to Tolkien's, and I felt it worth mentioning that we might not have orcs at all if it weren't for Tolkien's writing, since he created them (as far as I know). The term itself didn't refer to a particular race of grey-green humanoids obsessed with war and bloodshed, and 'goblin' was an incredibly vague, broad term that could describe all kinds of fae creatures (dwarves included!).
Sitting with this thought has brought an odd idea to the front of my brain: did Tolkien invent the concept of structured, clearly delineated fantasy races? Before his works, 'elf' could broadly refer to any number of creatures, from boggarts to christmas elves or even the progenitor álfar, but after, the idea of 'Elf' or 'Dwarf' means something *very* specific. This extends beyond his own depictions, as well. A 'fairy' could be thousands of things, and even a people as mythologically cogent as the Tuatha de Dannan had a great deal of diversity. Now, though, 'fairy' refers almost exclusively to pixies or more alien elf-like creatures. The distinction of 'wyvern' and 'dragon' was a purely heraldric one, but now it's a frequent bone of taxonomic contention.
Other authors walk a similar tightrope: the Atlantean's of Howards fiction are poorly defined and present only in isolated clusters or as individuals, and their actual physical descriptions are spare at best. Man-apes are simple and straight forward (and sometimes have wings!), and the various aliens of Lovecraft's work are, quite intentionally, sketchy and vague. Even the Deep Ones are left with a bare-bones definition, with little more detail than 'they look like fish and worship these evil things' (Dagon and Hydra or Cthulhu, depending on the story). The various martians of early 20th century fiction exist more as bogeymen than actual cultures. The only other clearly defined and explored race with hard-set descriptions and culture that wasn't just 'humans but a different color' that I can think of were the Green Martians of Burrough's John Carter.