You could also try to split the south america abstract from http://download.geofabrik.de/osm/ directly with your splitter areas.list file (I suppose you’ve splitted now Argentina?)

java -Xmx1500m -jar splitter.jar --output=pbf --split-file=areas.list --overlap=3000 south-america.osm.pbf

The idea is that the coastline outside of the countryborders are complete and not broken.