Looks like the Vervet Monkeys have either been phased out or the individuals passed away. I wouldn’t say I ever seen any of them other than the lone individual who was held in a separate enclosure but in any case it is sad to see a rare species disappear like that. I don’t think there are many in American zoos anyways. The old Vervet monkey exhibit has new inhabitants in the form of 1.3 Red tailed guenons. Most likely a recommendation since it appears to be a breeding group but I could be wrong.