Two new records of exotic spiders in Argentina (Arachnida: Araneae).

Two exotic spider species are reported for the first time in Argentina: Ozyptila praticola (C.L. Koch) (Thomisidae) and Microctenonyx subitaneus (O. Pickard-Cambridge) (Linyphiidae), being the former the first record from the southern hemisphere. The specimens were found in the leaf litter and under tree barks of modified environments in three localities in the southeast coast of Buenos Aires province. We propose the monitoring and study of the ecology of these new spider populations in order to elucidate potential risk for the local fauna. [ABSTRACT FROM AUTHOR]