Belostomatidae (Heteroptera: Nepomorpha) held in the Invertebrate Collection of the Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil: inventory and new distributional records

Belostomatidae is a family of giant water bugs with 52 valid species in Brazil. Here, we list 33 valid species housed in the Invertebrates Collection of the Instituto Nacional de Pesquisas da Amazônia – INPA, Manaus, Brazil. Of the total species examined, 26 had their distributional ranges increased (new records provided in parentheses): Belostoma amazonum Estévez & Polhemus (Mato Grosso and Roraima); B. aurivillianum (Montandon) (Rondônia); B. bosqi De Carlo (Maranhão); B. candidulum Montandon (Mato Grosso do Sul); B. carajaensis Ribeiro & Estévez (Amazonas); B. dallasi De Carlo (Bahia and Pará); B. dentatum (Mayr) (Roraima); B. denticolle Montandon (Roraima); B. dilatatum (Dufour) (Maranhão); B. discretum Montandon (Rio Grande do Sul); B. elongatum Montandon (Paraná); B. estevezae Ribeiro & Alecrim (Amazonas); B. fittkaui De Carlo (Roraima); B.  gestroi Montandon (Pará); B.  guianae Lauck (Brazil, in Roraima); B.  micantulum (Stål) (Maranhão, Rio Grande do Norte, Rondônia and Roraima); B.  minusculum (Uhler) (Brazil, in Amazonas, Pará and Rio Grande do Norte); B.  parvum Estévez & Polhemus (Amazonas and Roraima); B. plebejum (Stål) (Roraima); B. pygmeum (Dufour) (Pará); B. ribeiroi De Carlo (Mato Grosso do Sul); B. stollii (Amyot & Serville) (Roraima); Horvathinia pelocoroides Montandon (Rondônia); Lethocerus annulipes (HerrichSchaeffer) (Maranhão, Paraíba and Paraná); L. delpontei De Carlo (Amazonas and Pará) and L. maximus De Carlo (Acre, Amapá, Amazonas and Roraima). In addition, we provide a list of type and non-type specimens of Belostomatidae from INPA’s collection identified to the species level, photographs of these species and relevant taxonomic notes, when available. Key-Words. Aquatic insect; Giant water bugs; INPA; Taxonomy.

Currently, Belostomatidae has been recorded in all Brazilian states except Pernambuco and Sergipe, but the lack of reports for these two states undoubtedly is the result of a lack of sampling . The Brazilian region with the largest number of species recorded in the family is the South (with 32 species) and the region with the smallest number is the Northeast (with 14 species) . Biological collections in several Brazilian institutions have many unidentified specimens (Magalhães et al., 2005) or, with specimens identified only to the genus or family level, including Belostomatidae specimens. This fact is common to several other taxa and, according to Taddei et al. (1999), biases our understanding of diversity in the region, especially because some of these specimens can represent new species. There are several reasons for   the lack of species-level identification of the specimens housed in taxonomic collections, the main one being the lack of trained taxonomists.
The Invertebrate Collection of the Instituto Nacional de Pesquisas da Amazônia (INPA), located in Manaus, Amazonas state houses three type specimens of Belostomatidae: Belostoma nessimiani Ribeiro & Alecrim, 2008, Belostoma ripicolum Lanzer-de-Souza, 1992 junior synonym of Belostoma dilatatum (Dufour, 1863), according to Ribeiro (2007), and Lethocerus paraensis Lanzerde-Souza, 1991junior synonym of Lethocerus maximus De Carlo, 1938, according to Perez-Goodwyn (1997. In addition to these type specimens, INPA's collection houses many non-type specimens that are unidentified, mainly representing the North region, with some species being exclusive to the Amazon region. The objectives of this study are to identify at the species level all the giant water bugs housed in the Invertebrate Collection of INPA and provide a list with type and non-type specimens in this collection, with relevant taxonomic notes (when available), photographs of all species listed, and new distributional records.
One representative of each species was photographed using a stereoscopic microscope (Leica M165C), with a digital camera DFC420 and Leica Application Suite V3.6 digital image processing software. Comments were added indicating the new records and relevant taxonomic notes.
The maps were made in the DIVA-GIS software, version 7.5.

RESULTS AND DISCUSSION
A total of 628 Belostomatidae specimens were examined belonging to 33 species, 29 of which belonged to the genus Belostoma (distributed in 11 species groups), three species belonged to the genus Lethocerus, and two genera had only one species each: Horvathinia pelocoroides Montandon, 1911 and Weberiella rhomboides (Menke, 1965). The species are listed below, including type specimens deposited in the collection. The most abundant species was B. discretum Montandon, 1903b -with 257 specimens and the least abundant, with one specimen each, were B. carajaensis Ribeiro & Estévez, 2009, B. costalimai De Carlo, 1938  . The state with more new records was Roraima with nine species. In addition, we report two new records for Brazil -Belostoma guianae Lauck, 1962 and B. minusculum (Uhler, 1884), increasing the number of giant water bugs in the country to 54.
Knowledge of the diversity of Belostomatidae species from the Invertebrate Collection of INPA is summarized in this study. The taxonomic information and new geographic records mentioned here could provide input to biodiversity and biogeographical studies, as well as environmental monitoring.     Notes: This is the first record of B. amazonum to Mato Grosso and Roraima states (Brazil).

Discretum group sensu Lauck (1963)
Diagnose: Scutellum does not reach the nodal line; eye subtriangular and beak with segment I conspicuously shorter than II.