www.mammalogy.org © The Author(s) 2021. Published by Oxford University Press on behalf of the American Society of Mammalogists, www.mammalogy.org. 134 Lagothrix flavicauda (Primates: Atelidae) José E. Serrano-Villavicencio, 1,2,3, Sam Shanee, 4,5, and Víctor Pacheco 3,6, 1 Pós-graduação em Sistemática, Taxonomia Animal e Biodiversidade, Mastozoologia, Museu de Zoologia, Universidade de São Paulo, Avenida Nazaré, 481, CEP 04263-000, Ipiranga, São Paulo, SP, Brazil; serranovillavicencio@gmail.com 2 Centro de Investigación Biodiversidad Sostenible (BioS), Av. San Martín 278, Urb. Clarke, Piura, Perú 3 Departamento de Mastozoología, Museo de Historia Natural de la Universidad Nacional Mayor de San Marcos, Av. Arenales 1256, Lima 15072, Lima, Perú 4 Neotropical Primate Conservation, Windrush, Looe Hill, Torpoint PL11 3JQ, United Kingdom; sam@neoprimate.org 5 Nocturnal Primate Research Group, Oxford Brookes University, Oxford OX3 0BP, United Kingdom 6 Instituto de Ciencias Biológicas “Antonio Raimondi”, Facultad de Ciencias Biológicas, Universidad Nacional Mayor de San Marcos, Av. Venezuela s/n cuadra 34, Lima-1, Perú; vpachecot@unmsm.edu.pe Abstract: Lagothrix flavicauda (Humboldt, 1812), commonly known as the yellow-tailed woolly monkey, is one of the largest New World primates. Its diet is based on fruits and leaves, and occasionally flowers, buds, epiphyte roots, invertebrates, and some vertebrates. It is endemic to the cloud forests of northern Peru, in Amazonas, San Martín, Huánuco, Junín, La Libertad, and Loreto departments at elevations from 1,000 to 2,800 m. It lives in groups of up to 30 individuals. Lagothrix flavicauda is listed as “Critically Endangered” (CR) by both the International Union for Conservation of Nature (IUCN) and under Peruvian legislation, and on Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Key words: cloud forests, endemic, Peru, primate, yellow-tailed woolly monkey Resumen: Lagothrix flavicauda (Humboldt, 1812), comúnmente conocido como mono choro de cola amarilla, es uno de los primates más grandes del Nuevo Mundo. Su dieta está basada principalmente en frutas y hojas, pudiendo consumir ocasionalmente flores, brotes, raíces epífitas, invertebrados y algunos vertebrados. Es endémico de los bosques montanos del norte del Perú, en los departamentos de Amazonas, San Martín, Huánuco, Junín, La Libertad y Loreto a elevaciones de 1,000 hasta los 2,800 m. Vive en grupos de más de 30 individuos. Lagothrix flavicauda está clasificado como “Críticamente Amenazado” (CR) por la Unión Internacional para la Conservación de la Naturaleza (IUCN) y por la legislación peruana. Adicionalmente, se encuentra en el Apéndice I de la Convención sobre el Comercio Internacional de Especies Amenazadas de Fauna y Flora Silvestres (CITES). Palabras clave: Bosques montanos, endémico, mono choro de cola amarilla, Perú, primate Synonymies completed 10 October 2020 DOI: 10.1093/mspecies/seab013 Version of Record, first published online October 11, 2021, with fixed content and layout in compliance with Art. 8.1.3.2 ICZN. Nomenclatural statement.—A life science identifier (LSID) number was obtained for this publication: urn:lsid:zoobank.org:pub: 5F48507B-673C-475A-846E-7642A021F471 Lagothrix É. Geoffroy Saint-Hilaire, 1812 Simia: Humboldt, 1812a:343. Part; not Simia Linnaeus, 1758. Unavailable name (ICZN 1929:26, Opinion 114). Lagothrix É. Geoffroy Saint-Hilaire, 1812:106. No type spe- cies mentioned; type species S[imia]. lagotricha Humboldt, 1812, by subsequent designation (I. Geoffroy Saint-Hilaire 1851). Gastrimargus Spix, 1823:39. No type species mentioned. Oreonax Thomas, 1927a:156. Described as a subgenus of Lagothrix; Thomas (1927c:596) applied the name as a genus with type species Oreonax hendeei [= Lagothix flavicauda], by monotypy. Context and Content. Order Primates, suborder Haplorhini, infraorder Simiiformes, parvorder Platyrrhini, family Atelidae, subfamily Atelinae. Two species of Lagothrix are recognized, Lagothrix flavicauda and L. lagothricha. The latter was known Mammalian Species 53(1010):134–144 Downloaded from https://academic.oup.com/mspecies/article/53/1010/134/6388362 by ASM Member Access, serranovillavicencio@gmail.com on 11 October 2021