Indeed this does appear Spanish colonial, and seems to be an interesting hybrid of the bilbo type guard system, as well as reflecting the influence of European smallswords. The scalloped type edge of the shellguard is further evidence of the colonial possibilities, as well as the shape on the terminals and elements on the guard.
The blade looks to be one of the heavy military type broadsword blades that are now thought to have been actually Solingen made c.1770's and typically have the 'Spanish motto' in the triple fullers.
The large initials appear to be of either an owner or possibly a unit? In any case they would not be makers initials as far as I know.
The only associations with espada ancha would be that during this period, many of them carried these type blades, often reduced in length. The scalloped shell theme also occurred on some espada ancha in a flat extension of the guard that was like a large langet parallel to the blade.
Very nice! and its interesting to see a 'smallsword' type example that seems to be contemporary with many of the 'bilbo' swords, probably end of the 18th to early 19th century, and probably for an officer.
All best regards,