Actually the 'perillo', with reference to the discussion on this rapier, is a red herring .
I do recall the Beraiz work, and thank you Fernando for sharing it with me several years ago in work I was doing researching the running wolf. The connections between the well known Passau wolf and the mark seen on some of Julians blades, though like the wide variation in the running wolf, it can be seen in many forms, often even rampant which the running wolf is not.
Getting to this interesting rapier, it appears to me to be a courtly rapier made in Continental smallsword style of the latter 18th century, and with the scallop shell guard of hilt forms consigned to Spains colonies in the Americas. As noted, these type of shellguards are well known on espadas from Brazilian centers, as well as other port regions of the Spanish trade sphere.
These scallop shell guards with similar striations are seen on espadas provenanced to Brazil as late as mid 19th century, but are also known on espada anchas from the Santa Fe region c.1780s and other similar arming type swords of similar period.
The blade is similar to Solingen made trade blades for Spanish export to the colonies from the early part of the 18th century, possibly even earlier. These were intended for the hilting and remounting of the traditional rapiers long favored by Spanish gentry and worn much longer in the colonies than on the Continent. The hilt resembles guards seen on Spanish hunting type hangers from the 17th century, which also were favored for colonial wear in the same manner and well illustrated by the development of the espada ancha swords worn on the frontiers of New Spain.
Naturally with the proud traditions of Spain reflected by the gentry of the colonies in thier older style weapons would quite likely carry motif which recalled the military orders of chivalry , with the scallop shell of St. James of Compostela being foremost. Spains Order of St. James of Compostela and its equivilent in Portugal the Order of St. James of the Sword, were two of such orders.
Just added painting of St. James by Rembrandt 1661 with scallop shell worn on his shoulder, symbol of pilgrims to Compostela.