Forgive me if this is old news. I'm tired and it's late; that's my excuse and I'm sticking with it GUALDA-BARROS, Juliana; NASCIMENTO, Fabio Oliveira do and AMARAL, Marilia Kerr do. A new species of Callicebus Thomas, 1903 (Primates, Pitheciidae) from the states of Mato Grosso and Pará, Brazil. Pap. Avulsos Zool. (São Paulo) [online]. 2012, vol.52, n.23, pp. 261-279. ISSN 0031-1049. Available free online: http://www.scielo.br/pdf/paz/v52n23/a01v52n23.pdf
How did they get the specimens to photograph and do the skull examination? Clearly some of the monkeys are dead.
With a permit of capture or collection of biological material given by Brazilian Government! Of course some are dead they are part of the zoological collection of USP Museum in São Paulo.