Checklist of chelonians from the upper Madeira River and the lower Madeira-Purus interfluvium (Brazilian Amazon), including a range expansion for Podocnemis sextuberculata Cornalia, 1849

We present data on occurrence of chelonians for the Madeira River (southwestern Amazon, Brazil). Sampling was undertaken along the BR-319 Highway in the Madeira-Purus interfluvium and along a 125‑km stretch of the upper Madeira River. Findings were contrasted with a checklist of species expected to occur in the region according to current distribution maps, and with literature data for the Madeira subbasin. Out of 12 expected species, we recorded five in the Madeira-Purus interfluvium (three other species were registered by other recent voucher-based studies in the region), and eight species in the upper Madeira region. Podocnemis expansa (Schweigger, 1812) and P. unifilis Troschel, 1848 occurred below and inbetween the upper Madeira rapids. Podocnemis sextuberculata Cornalia, 1849 had its range extended by over 700 km, but may be limited upriver by the rapids. Mesoclemmys gibba (Schweigger, 1812) and M. raniceps Gray, 1855 occurred sympatrically along the river. Chelonian diversity along the lower and upper Madeira appears to be complementary.