Abstract
Mammarenaviruses are bi-segmented RNA viruses. They encompass viruses responsible for several severe diseases in humans. While performing a de novo assembly of a new virus found in a wild single-striped grass mouse in Tanzania, we found a single S but two divergent L segments. Natural co-infections, common within reptarenaviruses in captivity, were never reported for mammarenaviruses and never in a wild sample. This finding can have implications for virus evolution as co-infection could trigger viral recombination/reassortment in natural reservoirs.