Terrestrial gastropods from caves in Serra dos Carajás, eastern Brazilian Amazon, with the description of two new species (Eupulmonata, Stylommatophora).

The terrestrial gastropod fauna of Brazil is poorly studied, and cave gastropods remain largely unknown in the region. This study provides an initial assessment at the cave-dwelling gastropods of Serra dos Carajás, Pará state, northern Brazil, based on three years of research expeditions to the area. Of the 31 caves explored, 15 contained gastropods. In total, seven species were recorded, four Achatinidae and three Scolodontidae, including one new species in each family (described herein): Rectobelus arsayae sp. nov.; Dysopeas sp.; Leptinaria parana Pilsbry, 1926; Leptinaria unilamellata (d'Orbigny, 1838); Scolodonta carajaensis sp. nov.; Systrophia siolii Haas, 1955; Tamayoa decolorata (Drouët, 1859). Systrophia siolii, however, occurs only in the epigean forested areas, not inside the caves. This study provides the first record of modern specimens of Rectobelus in Brazil, the first record of Tamayoa decolorata in Brazil, and major range extensions (>500 km) of Leptinaria parana and Systrophia siolii in Pará, both of which are endemic to this state. Finally, Nannobeliscus Weyrauch, 1967 is here considered a synonym of Rectobelus Baker, 1927, resulting in the new combination Rectobelus silvaevagus (Weyrauch, 1964), comb. nov.; and Nannobeliscus mariaisabelae Miquel & Jaime, 2018 is considered a junior synonym of Rectobelus birabeni (Hylton Scott, 1946).