Diversidade e distribuição das espécies de Ranatra Fabricius, 1790 (Hemiptera: heteroptera: nepidae) do estado do Maranhão, Brasil

Abstract

Representatives of Ranatra Fabricius (Nepidae) are predatory water insects and are popularly called water scorpions because they have a breathing siphon at the rear end of their abdomen (seventh abdominal section). These insects live on vegetation, particularly associated with aquatic macrophytes and submerged roots on the banks of Lentic and Lotic waters. Ranatra includes about 120 species distributed worldwide, 35 of which are known from Brazil. However, there are no records for Maranhão or for the NE region as a whole, indicating a gap in the taxonomic and distributional knowledge of this group in the region. The aim of this work was therefore to know the diversity of Ranatra species present in Maranhão, to map the points of their distribution and to establish an identification key for the species from Maranhão. The samples were collected using a D (Rapiché) aquatic entomological network with a mesh size of 1 mm and by active searching day and night in different substrate types near the banks of water bodies. The collected samples were fixed in 80% alcohol and stored at the Aquatic Entomology Laboratory (LEAq) at UEMA, Campus Caxias. One specimen of each species was photographed and the diagnostic characters are presented for comparison. Distribution maps have been produced showing historical and new distribution records for each species. The male of R. mixta has been described and illustrated and a key to identifying the species present in the state has been established. A total of 138 specimens were identified, 73 males and 65 females distributed across eight species: Ranatra costalimai, R. doesburgi, R. macrophthalma, R. mediana, R. mixta, R. parvula, R. rabida and R. sarmentoi all set new records for Maranhão and the last new record for Brazil and distribution gaps across the genus can be closed, thus contributing to future work related to the group.