Hi @loarie! According to "Calling Frogs by Their Name: Long-Lasting Misidentification of Tetraploid Frogs of the Genus Odontophrynus (Anura: Odontophrynidae)" (2022) the true O. americanus (whose type locality is in northern Patagonia, that's southern Argentina) is restricted to some localities in southern and western Argentina; the species called O. americanus in the rest of the country and also tropical Uruguay, Paraguay, and Brasil is actually a different species, called O. asper: https://bioone.org/ContentImages/Journals/hmon/36/1/HERPMONOGRAPHS-D-21-00004/graphic/WebImages/img-z6-1_80.jpg (I can send you the full paper)

This was already hinted by Rosset in 2017, but it was widely accepted by the scientific community last year: https://bibliotecadigital.exactas.uba.ar/download/tesis/tesis_n6211_Rosset.pdf

Odontophrynus asper is already in the Inaturalist database. I'm making the corresponding taxon change, which will send O. americanus observations in places where it's not distributed to O. asper, and leave observations of O. americanus in places where it's distributed unchanged. But apparently I need a another curator's approval to do it.