A novel hepatitis B virus species discovered in capuchin monkeys sheds new light on the evolution of primate hepadnaviruses.

•A divergent HBV species termed CMHBV was discovered in Brazilian capuchin monkeys.•CMHBV and the related WMHBV use the same receptor as HBV to infect human cells.•CMHBV may cause chronic hepatitis B, potentially enabling new animal models.•Primates may have been carrying HBV-related viruses for millions of years.•New World HBV genotypes were likely introduced during the peopling of the Americas.