Humboldt's Night Monkey, the red-necked version. Also known as an owl monkey due to nocturnal habits. Found through much of the western Amazon basin, photo from Sacha Lodge Resort, eastern Ecuador. In context at www.dixpix.ca/Amazon/fauna/primates/index.html
Die Sugthiere in Abbildungen nach der Natur /.Erlangen :Expedition des Schreber'schen sugthier- und des Esper'schen Schmetterlingswerkes [etc.,1774]-1846..biodiversitylibrary.org/page/31078156