CARTA will not comment on my models, but I will comment on theirs. Speciation of primates requires reproductive isolation (no gene flow) and different environmental conditions (selection pressures).

Referring to the red letters I have added to CARTA's evolutionary tree (phylogeny), this is where and how the taxa might have speciated:

A: Old World Monkeys lived in Africa and Asia
B: Some Monkeys rafted to South America and evolved into New World Monkeys.
C: Some Monkeys became isolated in Asia and evolved into Gibbons
D: Some Gibbons rafted to islands without large predators (Borneo, Sumatra?) They evolved into the large sluggish Orangutans
E: Some Orangutans rafted to Africa, and evolved into Gorillas. They are large because they eat large quantities of low quality foods.
F: Some Gorillas rafted down the Congo River and evolved into Chimpanzees. They are smaller because they search more for higher quality foods.
G: Some Chimpanzees became isolated on Bioko and evolved into Humans. They are unique because of their marine habitat and no predators.
H: Some Chimpanzees became isolated south of the Congo River and evolved into Bonobos. Their habitat and diet is similar to Chimpanzees.

https://carta.anthropogeny.org/resources/phylogeny