Review of chelid and emydid turtle distributions in southern South America with emphasis on extralimital populations and new records for Argentina

There are many cases of animals reported in localities away from natural areas of distribution for the species. With respect to native freshwater turtles of Argentina and bordering countries, several populations (and single specimens) were reported for areas that cast doubts about their origin, due to not only the long distance from other known localities but also the geographical barriers that are in between. The present work provides a review of localities of the native turtle species Hydromedusa tectifera, Phrynops hilarii, Acanthochelys pallidipectoris, A. spixii and Trachemys dorbigni in Argentina, Bolivia, Brasil, Paraguay and Uruguay, and adds new records for some of these species for Argentina. We also employ an analysis to recognise core and extralimital populations, and a methodology based on five criteria that must be taken into account to elucidate if one extralimital turtle record is the result of anthropogenic action or a case of natural occurrence. Finally, we discuss about the origin of extralimital reports of turtles of the mentioned species.