Thanks so much for the response Gonzalo.
Yes, the blade is indeed too long for the literal 'espada ancha', which in Spanish means of course 'wide, heavy or large' sword from what I understand.
The term 'espada ancha' has become generally applied to both civilian sidearms carried by the hidalgos on thier estates as well as the heavy common swords carried by the Soldados de Cuero on the frontier. The application may well be compared to the term nimcha (actually means short sword in Arabic) but the blades on these are typically full length.
The grip with nock near the pommel, as seen on these Moroccan sa'ifs did probably influence the Spanish colonial hilts in some degree.It is important to note that the espada ancha hilt was also heavily influenced by 17th century hangers, such as the Hounslow hangers originally intended as hunting hangers. These were swords of the gentry, much as the espada ancha came to be in New Spain.The Hispano-Moresque jineta in the form I think of seems to be more in line with traditional swords of the earlier periods, and if I recall correctly had the downturned quillons. I think there is likely more explanation involved in 'jineta' as the Moorish warriors in both the Maghreb and in Andelusia.
There was of course quite considerable influence culturally as you mention, beginning with the Conquistadors, and the Moorish influence was profound throughout Spain's colonies.
When I first obtained one of these shellguard espadas, I thought it must be from Spanish colonies in Morocco. One reason was the British blade on it which was clearly from end of the 18th century and the nimcha style hilt that suggested Morocco. The clamshell seems to be of great importance in the Spanish tradition with its association to St.James of Compostela. The bird on the hilt as noted does not seem to be a raptor, so would not be the eagle of Mexican lore, so I am wondering if it might be the pelican or other bird more in line with Christian tradition. With that, the asterisk type star on the inner langet may be a stylized version of the Jerusalem cross, or an eight point cross. The Jerusalem cross had the four arms, with smaller crosses inside each quadrant and may have been interpreted as eight points . Not too sure on that, or if the device had meaning specifically as it is on nonvisible langet.
Teodor is right!
As always my posts are anything but brief, but I really am just sharing information I have found, or observations from researching over the years. I always look forward to hearing other observations and thoughts ...never stop learning!