not a species from Argentina:
Poecilia vivipara Bloch & Schneider, 1801
Koerber, S. & T.O. Litz (2014):
On the erroneous records of Poecilia vivipara from Argentina.
Ichthyological Contributions of PecesCriollos 33: 1-4
abstract (from publication):
Poecilia vivipara has been reported as being found in the freshwaters of Argentina since 1913. After analysis of the respective literature these accounts are considered erroneous as in no contribution a specimen from Argentina was listed.