Faecal DNA and camera traps detect an evolutionarily significant unit of the Amazonian brocket deer in the Brazilian Atlantic Forest

The Amazonian grey brocket deer ( Mazama nemorivaga ) is a large mammal species that until now has been assumed to be limited to the Amazon region and has not been categorized to be threatened. In this study, we provide evidences, obtained by camera traps and faecal DNA, of the existence of two populations of this species in the Brazilian Atlantic Forest, more than a thousand kilometres away from its assumed distribution limit. Furthermore, we employed genetic analysis to identify the collected faecal samples using detection dogs in six protected areas that were within 500 km of the first photographic records. Phylogenetic analysis, performed on hair samples, indicated that these populations were genetically related to the M. nemorivaga population of the western Amazon. The discovery of these populations emphasizes the importance of noninvasive techniques for species detection of elusive or rare populations. It is necessary to re-evaluate the conservation status of this species, with special attention to the detected populations (Linhares-Sooretama forest complex and the Una Biological Reserve). The conservation of these two new populations of evolutionarily significant units is urgent, and we recommend the adoption of measures against highly impacting deer threats, such as hunting and predation by domestic dogs. Finally, before any drastic population management is taken, it is necessary to determine whether there is historical or recent genetic isolation among the M. nemorivaga populations of the Atlantic Forest.