The Roosevelt – Rondon expedition marmoset (Mico marcai) : unveiling the conservation status of a data deficient species

The Roosevelt-Rondon Expedition marmoset, Mico marcai, was collected in 1914 and to date, all information on this species comes from three skins brought back by the Expedition and two additional skins collected in the 1990s. It is no surprise then that M.marcai has been classified as Data Deficient (DD). Given that Mico marcai’s suspected range sits on the path of the advancing Brazilian “Arc-of-Deforestation”, it is urgent that relevant data be collected to assess this taxon. Here we present the first comprehensive field data on the distribution, population size and threats on M. marcai with the goal of removing the species from the DD category. From 2012 to 2015, we surveyed for the species in 11 localities, in and around the Marmelos-Aripuanã interfluve, and estimated density using distance sampling on 10 transects. We also used spatial predictive modelling to project the amount of habitat that will be lost within its range in 18 years under different deforestation scenarios. We found marmosets in 14 localities and calculated its Extent of Occurrence to be 31,073 km2. We walked 271 km and detected 30 marmoset groups, allowing us to estimate their density to be 8.31 individuals/km2 and a total population of 258,217.71 individuals. By a “Business as usual” scenario, 20,181 km2 of habitat will be lost in three marmoset generations (~18 years), compromising 33% of the species’ range. Accordingly, M. marcai should be classified as globally Vulnerable under category A3c. Following our study, we propose the Amazonian marmosets, genus Mico, should undergo similar re-assessment as their ranges all fall in the path of the Arc-of-Deforestation. Keywords: Amazonian marmosets, Conservation Status, Data Deficient, Habitat Loss, Southern Amazoni

On the geographic distribution of the bald uakaris (Cacajao calvus ssp.) in Brazilian Amazonia

An understanding of a species’ geographic distribution is essential to assess, plan, and develop strategies for its conservation. The geographic distribution of the bald uakari, Cacajao calvus, and its component subspecies has been poorly investigated, with disjunct distributions being reported in Brazil and Peru. In this study, we reveal new records of bald uakari occurrence based on multi-year surveys, a literature review, and an examination of vouchers available in six zoological collections, clarifying the geographic distribution of all subspecies. We confirm that C. c. calvus has a disjunct distribution with populations along the rios Tarauacá and Pauini, 250 km away from those on the left bank of middle Rio Juruá and lower Rio Jutaí; and 650 km from the population of the Mamirauá Sustainable Development Reserve (Mamirauá SDR). Cacajao c. rubicundus has a disjunct distribution with three isolated populations 1) inhabiting the flooded forests of the Rio Solimões and the Paraná (channel) Jacurapá, 2) the left bank of the lower Rio Jutaí; and 3) in the Auati-Paraná. Cacajao c. novaesi has the smallest geographic distribution of the bald uakaris, occurring only in the Gregório-Tarauacá interfluvium. Cacajao c. novaesi and C. c. calvus are separated by the Rio Tarauacá, which is also a significant geographic barrier for other primates, including titi and saki monkeys. We also confirm the occurrence of Cacajao c. ucayalii in Brazil in the Serra do Divisor National Park. This Peruvian subspecies has the most extensive range, with isolated populations found in areas completely separated from the lowlands. The patchy distribution of Cacajao calvus provides a unique opportunity to understand how local environmental variation may have promoted ecological flexibility for the successful establishment of isolated populations