So I've been cleaning up a mummified Howler Monkey skull for a friend and we're both trying to figure out which species it is. I remember someone on here who works with a university or museum who specializes in monkeys and primates, would you be able to help? The skull originates from Rio Chambria Peru so I've narrowed it down to Jurua Red Howler, Purus Red Howler, Venezuelan Red Howler, Mantled Howler, or Ecuadorian Mantled Howler just by checking to see which species are native to Peru. If anyone could help at all please let me know and I'll send or upload pics of the skulls before cleaning and what it looks like now. It is not done being cleaned but I removed a lot of the dried skin and flesh so you can at least see the base shapes and details of the skull.