First record of albinism in the black-fronted titi monkey using a dual-sensor drone: an unprecedented case in Neotropical primates.

Only a few records of pigmentation anomalies, particularly hypopigmentation conditions such as albinism, have been reported among Neotropical non-human primates. In Brazil, there are only 14 documented cases of pigmentation anomalies, with just two instances of albinism recorded within the Cebidae family. To our knowledge, no pigmentation polymorphisms have been documented in the Pitheciidae family to date. In this study, we report the first documented case of albinism in Callicebus nigrifrons (the black-fronted titi monkey) within the largest remnant of the Atlantic Forest in the State of Minas Gerais, Brazil. This observation was made using a drone equipped with 4K cameras and thermal infrared sensors. This primate exhibited characteristics such as the absence of pigmentation in its fur, as well as in its palms of its hands and feet, and dark red eyes. It was observed in a group composed of two other individuals displaying typical coloration. The group's behavior was normal, showing no signs of exclusion toward the albino individual. Potential causes of albinism in C. nigrifrons may include genetic or environmental factors, or combined pressures, though these remain speculative. This is the first confirmed case of albinism in the Pitheciidae family and the first record of such a phenomenon using drone technology in the wild. Our findings underscore the potential of drones for detecting low-frequency phenotypic traits in elusive species and reinforce the role of protected areas such as the Rio Doce State Park in safeguarding threatened and genetically distinct individuals.