Gerromorpha (Hemiptera: Heteroptera) from the Metropolitan Region of Santarém, Brazil, including three new species of Microvelia Westwood, 1834 (Veliidae: Microveliinae).

Aiming to fill gaps concerning the diversity and distribution of Gerromorpha in the Amazon, a survey of the semi-aquatic bugs from the MRS is presented. Collections were made in 33 aquatic ecosystems in the different phytophysiognomies within this area from July 2019 to October 2020. As a result, a checklist with 44 species recorded from the three municipalities of the MRS is presented. Furthermore, three new species of the genus Microvelia Westwood, 1834 (M.belterrensis sp. nov., M.hamadae sp. nov. and M.sousorum sp. nov.) are described, two species are recorded for the first time from Brazil (Microveliaaschnakiranae Makhan, 2014 and Rhagoveliagraziae Galindo-Malagón, Morales & Moreira, 2021), two from Pará State (Microvelialongipes Uhler, 1894 and Paraveliadilatata Polhemus & Polhemus, 1984) and 15 from the MRS (Brachymetralata Shaw, 1933, B.shawi Hungerford & Matsuda, 1957, Tachygerrisadamsoni (Drake, 1942), Microveliapulchella Westwood, 1834, Rhagoveliabrunae Magalhães & Moreira, 2016, R.evidis Bacon, 1948, R.jubata Bacon, 1948, Calliveliaconata (Hungerford, 1929), Oioveliacunucunumana Drake & Maldonado-Capriles, 1952, Paraveliabullialata Polhemus & Polhemus, 1984, Striduliveliaalia (Drake, 1957), S.stridulata (Hungerford, 1929), S.strigosa (Hungerford, 1929), S.tersa (Drake & Harris, 1941) and S.transversa (Hungerford, 1929)).