Oligoryzomys chacoensis

Oligoryzomys chacoensis, also known as the Chacoan colilargo or Chacoan pygmy rice rat, is a rodent species from South America. It is found in the Gran Chaco region of southeastern Bolivia, southwestern Brazil, Paraguay, and northeastern Argentina. Its karyotype has 2n = 58 and FNa = 74.
It is one of the hosts of the hantavirus serotype Bermejo.