Complex sentence: The equatorial belt contracted after about 8 million years ago, and there is very little fossil evidence for the split--thought to have occurred around that time--of the hominin lineage from the lineages of gorillas and chimpanzees.
Split into simpler sentences: The equatorial belt contracted after about 8 million years ago. There is very little fossil evidence for the split of the hominin lineage from the lineages of gorillas and chimpanzees.