Lower to probably Middle Devonian bryozoans from western Argentina are reported. Five genera of trepostomes: Leptotrypa, Leptotrypella, Eridotrypella, Cyphotrypa, Boardmanella, and the cryptostome ?Pseudonematopora are described and figured. The paleobiogeographical significance of these bryozoans was analyzed in the context of Southern Gondwana during the Devonian. The group was considered as nearly absent from southwestern marine basins. In contrast with highly endemic groups, supporting the recognition of the Malvinokaffric Realm in this region, bryozoans reported are nearly cosmopolitan. The presence of those genera typical of warm-temperate, carbonate settings from low paleolatitudes, such as the Laurentian-European Eridotrypella, Leptotrypa, and Leptotrypella, or the Eurasians Boardmanella and ?Pseudonematopora, implies that these taxa were euritopic with remarkable capabilities for dispersion to reach high-latitude siliciclastic environments of the Southwestern Gondwanan basins.