Accurate Goblins?

Question

so I’m making a story where, as part of my world building, I take different monsters and make them as evolutionary accurate as possible. Anyways, today I would like to discuss the best way to design and evolve my goblins? I would like to evolve them from a type of primate although I’m not sure what type whether it be chimp, monkey, or Australopithecus. Here are the different qualities I’d like for them to have (if possible) and what kind of evolutionary pressures could lead to them from one of the aforementioned possible ancestors:

1. A tail (preferably medium length or long).
2. Pointed ears (can take it or leave it).
3. Between 2’6” to 4’0” at the tallest.
4. Having the same type of lifestyle as Australopithecus in that it mostly walks upright but is also tree dwelling.
5. Yellow eyes similar to lemurs (maybe because of them being nocturnal like lemurs).
6. Covered in hair like a chimp.
7. Larger lower canines that stick out of their lips in some individuals.

I realize my question is a bit open ended but I’d appreciate any help in deciphering what I should evolve them from and what pressures would require them to evolve said traits.

Answer 1

Apes, and why not Australopithecus?

The only thing in your goblins that can't be explained with an ape is the tail. Monkeys typically have tails, whereas apes do not. Apes can have fangs, but they are typically for fighting or mating displays. Fangs are typically noticeable on upper jaws in primates, but some have them on both upper and lower jaws, and if it were a mating display, selection would give you lower fangs. Yellow as an eye color tends to correlate with nocturnal animals, but I'm unaware of a reason yellow and nocturnal go together. If you want your species to be nocturnal, make the eyes large. Humans can have eyes that look yellow, so I see no barrier to your goblins having purely yellow eyes. Pointy ears can exist in humans, so there's no reason goblins couldn't have them and more dramatically due to selection or quirk of fate.

So-called hobbit people of the suggested size existed not all that long ago, as a result of an island environment that subsequently gave rise to pygmies, so the size is perfectly reasonable. Australopithecus was only slightly taller than your goblins, and the two groups are likely to be similar. If you want a tail for your goblins, I would suggest they re-evolved a tail and possibly a more monkey-like walk (on all fours, and along branches rather than brachiating) and this might account for slightly smaller size. You said nothing about intelligence, and apes tend to be more intelligent than monkeys. I assume you want tool users, and Australopithecus is fairly primitive, but they probably are capable of using tools. Why such a species would be more intelligent than Australopithecus would require some creativity about the evolution of intelligence, like a predatory lifestyle for skill and protein, and the need for tool use. Maybe your species started hunting monkeys and other tree-dwelling species. Nocturnal hunting also means your species may like caves (another goblin traditional environment) and small size would be favorable for such enclosed environments like hunting bats. Competition from other hominids would mean that small size and access to thick briars and small caves plus a nocturnal lifestyle keeps your goblin from competing too much with humans and the like.

Answer 2

You want a bipedal baboon.

source

Baboons have everything you need. 24 inch tail, covered with hair, little pointed ears. Terrestrial but can get into trees in a pinch. Beautiful golden eyes (this cutie is making her "mating face"). The teeth are no joke and they are weapons equal to taking on a leopard in the adult males.

Baboons are already pretty dang gobliny. The only thing about having them be nocturnal is that their cat predators are nocturnal too. If they were tool users and took pains to hunt down and kill predators in the area (like humans do) that might work out ok.