DISTRIBUTION OF CAIMAN-CROCODILUS-CROCODILUS AND CAIMAN-YACARE POPULATIONS IN BRAZIL

The distribution and relationships among populations of Caiman crocodi lus crocodilus and Caiman yacare were investigated throughout Brazil. Caiman c. crocodilus inhabits the drainages of the Rio Solimoes/Rio Am azonas, Araguaia, Araguari, Itapicuru, Paranaiba, Negro, Tapajos, Toca ntins, Xingu, and the rivers draining to the Atlantic Ocean on the nor thern coast of Brazil. It does not occur in the Rio Sao Francisco. Cai man yacare is endemic to the Rio Mamore, Rio Guapore, Rio Paraguai and Rio Parana river systems and all of their lowland drainages. The nort hernmost limit for C. yacare lies between Costa Marques (12 degrees 25 'S, 64 degrees 10'W) and Guajara Mirim, Pacaas Novos on the Rio Mamore (10 degrees 55'S, 65 degrees 15'W). Small populations of apparently h ybrid individuals were observed in the upper Rio AcrB, the Rio Abuna, the upper Rio Madeira, and the Rio Mamore between Guajara Mirim and Ab una. Caiman c. crocodiles and C. yacare populations are geologically s eparated and morphologically distinct. The taxonomic recognition of Ca iman species with overlapping distributions in the states of Mate Gros so and Mate Grosso do Sul appears to be without merit.