Lagothrix flavicauda

Abstract: Populations of the yellow-tailed woolly monkey (Oreonax flavicauda) persist in increasingly isolated, threatened cloud forests in scattered areas of the departments of San Martin and Amazonas, in northern Peru. No long-term research has been conducted on this species in more than 20 years. The range of O. flavicauda continues to suffer rapid and widespread deforestation. From June to August 2004,I was involved in selecting a site for an extended study of its behavior and ecology. Here I document the species' continued existence and status in the Bosque de Proteccion (Protected Forest) of Alto Mayo. Three sightings of O. flavicauda provided a group size of 17–20 individuals—higher than previous sightings by Mariela Leo Luna in the early 1980s, who observed an average group size of nine. The difficulty we encountered in finding groups in the study area suggests that yellowtailed woolly monkeys have a large home range. This and its large body size, low density, low reproductive rate, its restrictio...

Abstract: We summarize our re-examination and extension of the Groves (2001) parsimony analysis of Woolly monkeys, genus Lagothrix, which led him to conclude that the species flavicauda is not most closely related to lagotricha but to Ateles, the Spider monkeys. As a consequence, Groves further proposed that the Yellow-tailed woolly monkey should be assigned to a separate genus, Oreonax, previously erected by Oldfield Thomas (1927). Our analysis, while closely following his methods, samples a greater diversity of species and sub-species representing all the living ateline genera and makes minor revisions in Groves' data matrix of craniodental characteristics. With this broader analysis we show that Groves' cladistic results cannot be replicated except by duplicating his study using only a restricted range of taxa. A more wide ranging taxonomic sampling fails to link consistently flavicauda and other ateline species, in any particular cladogram topology, while the overall craniodental morphology of flavicau...