The Hydradephaga (Coleoptera, Dytiscidae, Gyrinidae, Haliplidae, Noteridae) of the Iberá wetlands, the second largest wetland area of South America.

This study presents the first inventory of Hydradephaga beetles from the Iberá wetlands, a natural reserve located in the province of Corrientes, Argentina. A total of 80 taxa were recognised, of which 62 are identified at the species level and 18 at the genus level. Of the four Hydradephaga families present in Argentina, Dytiscidae is the richest in terms of the number of genera and species (25 genera, 43 species), followed by Noteridae (6 genera, 32 species), Gyrinidae (2 genera, 3 species), and Haliplidae (1 genus, 2 species). The following five species are recorded for the first time in Argentina: Copelatus cf. inornatus Sharp, 1882; Bidessodes cf. evanidus Young, 1986; Neobidessus trilineatus (Zimmermann, 1925); Haliplus nieseri van Vondel & Spangler, 2008; and Suphisellus cf. pereirai Guignot, 1958. Additionally, eight species are reported for the first time in the province of Corrientes: Meridiorhantus orbignyi (Balke, 1992); Celina cf. parallela (Babington, 1842); Laccophilus cf. obliquatus Régimbart, 1889; Laccophilus cf. paraguensis Régimbart, 1903; Haliplus ornatipennis Zimmermann, 1921; Hydrocanthus paraguayensis Zimmermann, 1928; Mesonoterus crassicornis (Régimbart, 1889); and Suphisellus cf. rufipes (Sharp, 1882). The high diversity of Hydradephaga beetles recorded highlights the ecological significance of this protected area.