For the hominid lineage – all of our ancestors since our split with the chimpanzee/bonobo lineage – the fossil evidence for the human-chimpanzee last common ancestor (LCA) is scarce because: 1. Apes were extremely rare during the Miocene. 2. These apes lived in a narrow range of environments that were not preserved well in the fossil record (like forests). 3. The LCA lived in the Paleocene, a time from which we have essentially no fossil record. 4. Most of the primates known from the mid-Miocene are Old World monkeys, who are from a different Linnaean family than we are.