The Monkeys of the Islands of the Amazon Estuary, Brazil: A Biogeographic Analysis

In this report, based on field and collection studies, we present the first synthesis on the primate species living in the four main islands (Marajó, Gurupá, Mexiana and Caviana) of the Amazon estuary. Seven taxa (six cebids and one callitrichid) were recorded, which represent roughly 50 % of the extant primate species found on the continent. We used the Parsimony Analysis of Endemicity (PAE) to establish historical relationships among these four islands and the continental banks. Only one most parsimonious cladogram was found. It shows that : (a) the islands and the continents were once united; (b) the fragmentation of this ancient region occurred from the Atlantic Ocean towards the mainland. We suggest that this pattern of biogeographical relationships can be associated with the last major change in sea level during the Late Pleistocene-Holocene.