You would think there would be a high school biology teacher in Chile who would be happy to press gang some students into a field trip to find the answer.
Probably just a few hundred years, right?
In this case you need to be able to recognise only one species that is named and described and the genus can be assured looking at the third segment of the peduncle in the first antenna, eyes medium, gnathopod 1 fully subchelate, etc, etc.
Scholars should focuse in your studies, and let this kind of work for professionals, obviously. Amphipod specimens need to be dissected for identification, and is too easy to misplace, mistake or miss important facts, distroying unique valuable specimens for nothing.
But high school students aren't.
I can think only in one reason to not contact the chilean biologists, or visit Chile, and is a language barrier, easy to overcome since we have google translate and similar tools.
On the other hand, amphipods are really easy to keep in aquariums for many months. Females incubate its eggs under the legs in a sort of pouches (kangaroo style) and there is often a clear and obvious sexual dimorphism, so their reproductive life is not dificult to study at all. You can easily observe the breeding behaviour, clutch size, embriology, hatching, season and number of generations by year. Why they didn't it in all of those years is a mystery to me. (Shrug) maybe fear that the species would be disclosed as belonging to a yet described species and became a synonym?.
Most business performed in multi-nationals in "Sanhattan" (Las Condes/Providencia), for example, is conducted in English.
If the critter hitched a ride from Chile it's probably native to one of the harbors or bays.
Compare: amateur astronomer comet-hunters.