Mark, beautifully done!!! Congratulations

It really feels great to master the mysteries of these things, and its fun once you get going.
This certainly does not resemble any espada ancha I've seen, though these did get pretty crude in later times, and by the mid 19th century were essentially large Bowie knives. It does not rule out the innovative edged weapons created by Mexican blacksmiths later in the 19th century, which would be hard to accurately identify.
The unusual D guard and scrolled overlap at the pommel, which seems more characteristic for a quillon terminal and the gadrooned metal on the grip could lend toward Africa. With the style and shortened blade, maybe it could be a dirk from the Maghreb's 'nautical enterprises' ?
Interesting though!!!!
I look forward to your postings coming with this newfound skill!!! yay!
All the best,
Jim