Photographic catalog of marine fish otoliths. http://swfsc.noaa.gov/publications/TM/SWFSC/NOAA-TM-NMFS-SWFSC-483.pdf
paper of Chile scientists about otoliths-their contact details are included in the paper http://www.scielo.cl/scielo.php?pid=S0718-19572013000300019&script=sci_arttext
a digital database for otoliths, available online. http://digital.csic.es/bitstream/10261/5830/1/aforo.pdf
You should contact Dr. Sophia Perdikaris at CUNY Graduate Center, she is an otolith expert. If you google her coordinates are the first on the list and you can locate her email through that website.
The size would fit in with the finds I know from Europe, but having no experience with South-American fishes, I haven't got a clue which species they could belong to.
A fishermen from Easter Island told me he was bite very hard when he introduced his fingers thru the galls of 2 species: toremo and po'o poó (local names), both from the Carangidae family. Genders Seriola, Pseudocaranx for the central coast of Chile ? Deep fishing by 500 AD ? I do not think so...