La ocurrencia de moluscos en contextos arqueológicos es habitual, debido a la importancia de los mismos para la alimentación, para ámbitos rituales y simbólicos, para la fabricación de instrumentos y como material constructivo. Se sintetizan aquí los datos referentes al manejo diferencial de materiales malacológicos realizado por las poblaciones cazadoras-recolectoras prehispánicas que ocuparon las regiones Este, Centro-Sur y Oeste de Uruguay durante el Holoceno tardío, con especial referencia a la identificación taxonómica y a los usos inferidos. Se realizó un relevamiento bibliográfico exhaustivo y de materiales presentes en algunos acervos públicos, sumando información inédita, para profundizar en los modos de uso y procesos de intercambio intercultural regional. Los moluscos se asocian principalmente a los aspectos simbólicos (ornamentales y funerarios) de estas culturas y a actividades económicas vinculadas al consumo alimentario y producción de artefactos utilitarios. Desde el punto de vista contextual se asocian a espacios de actividades mayoritariamente domésticas, así como a otros que conjugan actividades diversas (domésticas, constructivas y/o funerarias) ubicados entre ca. 3300 14C años AP y 500 14C años AP.

Paraguay is a landlocked country with a central position in South America, and two main rivers of the La Plata Basin run through the country: Paraná and Paraguay rivers. This is the second-largest basin in South America and harbors an important molluscan fauna (Strong et al., 2008 Strong, E.E., Gargominy, O., Ponder, W.F., & Bouchet, P., 2008. Global diversity of gastropods (Gastropoda; Mollusca) in freshwater. Hydrobiologia 595(1), 149-166. http://dx.doi.org/10.1007/s10750-007-9012-6. http://dx.doi.org/10.1007/s10750-007-901... ; Pereira et al., 2014 Pereira, D., Mansur, M.C.D., Duarte, L.D.S., Oliveira, A.S., Pimpão, D.M., Callil, C.T., Ituarte, C., Parada, E., Peredo, S., Darrigran, G., Scarabino, F., Clavijo, C., Lara, G., Miyahira, I.C., & Lasso, C., 2014. Bivalve distribution in hydrographic regions in South America: historical overview and conservation. Hydrobiologia 735(1), 15-44. http://dx.doi.org/10.1007/s10750-013-1639-x. http://dx.doi.org/10.1007/s10750-013-163... ; Cuezzo et al., 2020 Cuezzo, M.G., Gregoric, D.E.G., Pointier, J.P., Vázquez, A.A., Ituarte, C., Mansur, M.C.D., Arruda, J.O., Baker, G., Santos, S.B., Ovando, X.M., Fernandez, M.A., Thiengo, S.C., Mattos, A.C., Silva, E.F., Berning, M.I., Collado, G.A., Miyahira, I.C., Antoniazzi, T.N., Pimpão, D.M., & Damborenea, C., 2020. Phylum Mollusca. In: Damborenea, C., Rogers, D.C. & Thorp, J.H., eds. Thorp and Covich’s Freshwater Invertebrates. London: Academic Press, 261-430, 4 ed., vol. 5: Keys to Neotropical and Antartic Fauna. http://dx.doi.org/10.1016/B978-0-12-804225-0.00011-3. http://dx.doi.org/10.1016/B978-0-12-8042... ). A total of 16 freshwater species of molluscs were reported as non-native from South America by Darrigran et al. (2020) Darrigran, G., Agudo-Padrón, I., Baez, P., Belz, C., Cardoso, F., Carranza, A., Collado, G., Correoso, M., Cuezzo, M.G., Fabres, A., Gregoric, D.E., Letelier, S., Ludwig, S., Mansur, M.C.D., Pastorino, G., Penchaszadeh, P., Peralta, C., Rebolledo, A., Rumi, A., Santos, S., Thiengo, S., Vigidal, T., & Damborenea, C., 2020. Non-native mollusks throughout South America: emergent patterns in an understudied continent. Biol. Invasions 22(3), 853-871. http://dx.doi.org/10.1007/s10530-019-02178-4. http://dx.doi.org/10.1007/s10530-019-021... . These authors reported the presence of seven non-native species in the La Plata Basin, from which were highlighted Corbicula fluminea (Müller, 1774), the Asiatic clam; and Limnoperna fortunei (Dunker, 1857), the golden mussel. Corbicula species arrived in South America in the 1970s and Limnoperna fortunei some years later (around the 1990s), both are widespread now (Darrigran et al., 2020 Darrigran, G., Agudo-Padrón, I., Baez, P., Belz, C., Cardoso, F., Carranza, A., Collado, G., Correoso, M., Cuezzo, M.G., Fabres, A., Gregoric, D.E., Letelier, S., Ludwig, S., Mansur, M.C.D., Pastorino, G., Penchaszadeh, P., Peralta, C., Rebolledo, A., Rumi, A., Santos, S., Thiengo, S., Vigidal, T., & Damborenea, C., 2020. Non-native mollusks throughout South America: emergent patterns in an understudied continent. Biol. Invasions 22(3), 853-871. http://dx.doi.org/10.1007/s10530-019-02178-4. http://dx.doi.org/10.1007/s10530-019-021... ; Miyahira et al., 2020 Miyahira, I.C., Pereira, L.S., & dos Santos, L.N., 2020. Non-native freshwater molluscs in the Neotropics: what can be learned from Brazilian reservoirs? Aquat. Invasions 15(3), 455-472. http://dx.doi.org/10.3391/ai.2020.15.3.06. http://dx.doi.org/10.3391/ai.2020.15.3.0... ; Hermes-Silva et al., 2021 Hermes-Silva, S., Ribolli, J., Ávila-Simas, S.D., Zaniboni-Filho, E., Cardoso, G.F.M., & Nuñer, A.P.D.O., 2021. Limnoperna fortunei-Updating the geographic distribution in the Brazilian watersheds and mapping the regional occurrence in the Upper Uruguay River basin. Biota Neotrop. 21(3), e20201175. http://dx.doi.org/10.1590/1676-0611-bn-2020-1175. http://dx.doi.org/10.1590/1676-0611-bn-2... ). Invasive species can promote modification of environmental and biological aspects of the invaded habitat (e.g., Darrigran & Damborenea, 2011 Darrigran, G., & Damborenea, C., 2011. Ecosystem engineering impacts of Limnoperna fortunei in South America. Zool. Sci. 28(1), 1-7. PMid:21186940. http://dx.doi.org/10.2108/zsj.28.1. http://dx.doi.org/10.2108/zsj.28.1... ; Sousa et al., 2014 Sousa, R., Novais, A., Costa, R., & Strayer, D.L., 2014. Invasive bivalves in fresh waters: impacts from individuals to ecosystems and possible control strategies. Hydrobiologia 735(1), 233-251. http://dx.doi.org/10.1007/s10750-012-1409-1. http://dx.doi.org/10.1007/s10750-012-140... ; Boltovskoy & Correa, 2015 Boltovskoy, D., & Correa, N., 2015. Ecosystem impacts of the invasive bivalve Limnoperna fortunei (golden mussel) in South America. Hydrobiologia 746(1), 81-95. http://dx.doi.org/10.1007/s10750-014-1882-9. http://dx.doi.org/10.1007/s10750-014-188... ), affecting not only native molluscs, but also other taxonomic groups. Understanding the distribution of invasive species is the first step to proposing strategies to mitigate the negative impacts.

A correction to this paper has been published: https://doi.org/10.1007/s10750-021-04580-3

Based on fish monitoring programs in the Uruguay River held during the 2023–2024 flood pulse, we report for the first time the presence of the following four species in the Uruguay river basin: Hemiodus orthonops Eigenmann & Kennedy, 1903; Cynopotamus kincaidi (Schultz, 1950); Brycon hilarii (Valenciennes, 1850); and Cnesterodon raddai Meyer & Etzel, 2001. Furthermore, three other species mentioned in literature but without formal records in scientific collections were confirmed for Uruguay: Schizodon borellii (Boulenger, 1900), Tetragonopterus argenteus Cuvier, 1816; and Hoplerythrinus unitaeniatus (Spix & Agassiz, 1829).