Belostomatidae Leach, 1815 (Insecta: Hemiptera: Heteroptera: Nepomorpha) of northeastern Brazil

. Belostomatidae Leach, 1815 (Insecta: Hemiptera: Heteroptera: Nepomorpha), also known as giant water bugs, is a family with 11 genera and about 160 described species, most of which are recorded from the Neotropical region. Knowledge about these bugs in northeastern Brazil is relatively poor


Introduction
Belostomatidae Leach, 1815 (Insecta: Hemiptera: Heteroptera: Nepomorpha) is a family of aquatic insects commonly known as giant water bugs, electric light bugs, or toe biters (Menke 1979).They are territories, only the first known record is provided.Maps were produced using QGIS ver.3.10.7 (QGIS Development Team 2020).Records based on uncertain data (e.g., only state is known) are displayed on the maps as question marks.

Results
A total of 150 specimens were examined, comprising 13 species of Belostoma and three species of Lethocerus.We report five new records from the Northeast Region of the country: Belostoma aurivillianum (Montandon, 1899); B. costalimai De Carlo, 1938;B. gestroi Montandon, 1900;B. harrisi Lauck, 1962;and B. nessimiani Ribeiro & Alecrim, 2008.Thus, the number of species recorded from the area is increased from 16 to 21.The state with the highest number of new records is Maranhão, with 10 species, followed by Piauí with two, and Ceará with one.Five species of Belostoma previously recorded from the Northeast Region (Ribeiro et al. 2021) were not represented in the material examined: B. amazonum, B. dallasi, B. foveolatum, B. horvathi, and B. plebejum.We present below a brief taxonomic treatment for each studied species recorded in the Northeast Region of Brazil, organized by subfamily, genus and species group according to Stefanello (2021) for Belostoma, followed by a key to all the species occurring in the Brazilian Northeast.An updated key to the species groups of Belostoma has been recently provided by Stefanello (2021).

Diagnosis
Ventral abdominal pubescence extending along genital operculum, covering entire margin of connexivum and part of sternites (Ribeiro 2007).

Distribution in northeastern Brazil
Maranhão.

Note
First records from the state of Maranhão and northeastern Brazil.
Belostoma dentatum species group sensu Ribeiro et al. (2017) This group consists of 18 species, six of which are recorded from northeastern Brazil.Total lengths range between 25.0 and 49.0 mm.They are characterized by the article II of the labium usually longer than article III, and the prosternal keel rounded or pointed and strongly developed (Ribeiro et al. 2017).

Distribution in northeastern Brazil
Bahia and Ceará.

Distribution in northeastern Brazil
Maranhão and Piauí.

Note
First records from the state of Maranhão.

Distribution in northeastern Brazil
Maranhão and Piauí.

Note
First records from the state of Maranhão.

Diagnosis
Belostoma foveolatum is very similar to B. elongatum, but can be distinguished by the width of the ventral diverticulum in ventral view, which is narrower than in B. elongatum, as well as by the shape of the body; phallosoma with the dorsal arms more separate at mid-length in dorsal aspect.Finally, the lateral margins of the ventral diverticulum are clearly more strongly curved than in B. elongatum (Ribeiro et al. 2017).

Distribution in northeastern Brazil
Ceará.

Distribution in northeastern Brazil
Maranhão.

Note
First records from the state of Maranhão and northeastern Brazil.
Belostoma denticolle species group sensu Estévez & Polhemus (2001) This group consists of four species, of which only one species is recorded from northeastern Brazil.
Total lengths range between 11.0 and 16.0 mm.They are characterized by the ventral diverticulum flat and the arms of the phallobase longer than the posterior portion of the phallobase.This group resembles the oxyurum group by the flat shape of the male genitalia, but differs from it by the narrower pubescence of the connexivum (Estévez & Polhemus 2001).

Diagnosis
Body elongate; clypeogenal cleft as long as clypeoloral cleft; anteoculus slightly shorter than interoculus; eyes globose, as wide as long; article II of the labium shorter than article III; prosternal keel acutely pointed, prominent; dorsal arms of phallosoma amost straight, not covering lateral margins of diverticulum (Estévez & Polhemus 2001).

Distribution in northeastern Brazil
Bahia.
European Journal of Taxonomy 932: 271-304 ( 2024) Belostoma dilatatum species group sensu Lauck (1964) This group consists of three species, of which two are recorded from northeastern Brazil.Total lengths range between 35.0 and 50.0 mm.They are characterized by the anteoculus longer than the interoculus and the eyes triangular, frontally elongated, with the lateral margin straight (Ribeiro 2007).

Distribution in northeastern Brazil
Maranhão and Paraíba.

Distribution in northeastern Brazil
Maranhão.

Note
First records from the state of Maranhão and northeastern Brazil.
Belostoma discretum species group sensu Lauck (1963) This group consists of a single species; thus, it is characterized by the species features listed below.

Distribution in northeastern Brazil
Maranhão.
European Journal of Taxonomy 932: 271-304 ( 2024) Belostoma oxyurum group sensu Lauck (1964) This group consists of seven species, of which only one is recorded from northeastern Brazil.Total lengths range between 12.0 and 21.2 mm.The species are characterized by male phallosoma straight with diverticulum of phallus flattened, circular and broad, without dorsal caudal protuberance, without depression in mid dorsal line, without developed ventroapical protuberance, and truncated at apex in ventral view; caudal laterodorsal margins; ventral abdominal pubescence well developed, covering about half of connexivum (slightly developed on penultimate visible segment) (Ribeiro & Estévez 2009).

Distribution in northeastern Brazil
Bahia.
Belostoma plebejum species group sensu Nieser (1975) This group consists of nine species, of which three are recorded from northeastern Brazil.Their total lengths range between 9.5 and 16.2 mm; The species are characterized by the diverticulum curved downward, elliptical (e.g., Fig. 35); the ventral abdominal pubescence covering about half of the connexivum, not extending to the sternites (Estévez & Polhemus 2007;Ribeiro & Alecrim 2008).

Distribution in northeastern Brazil
Maranhão.

Note
First records from the state of Maranhão and northeastern Brazil.

Distribution in northeastern Brazil
Bahia.
Belostoma stollii species group sensu Stefanello (2021) This group consists of two species, both of which are recorded from northeastern Brazil.Total lengths range between 31.0 and 39.5 mm.They share the well-developed longitudinal carina on the vertex, pronotum, and scutellum (Figs [12][13]; the concave vertex, slightly depressed in relation to the mesal margins of the eyes; and the pronotum and scutellum covered with golden-brownish setae (Lauck 1963).

Distribution in northeastern Brazil
Maranhão.

Distribution in northeastern Brazil
Alagoas and Maranhão.

Distribution in northeastern Brazil
Bahia, and Maranhão.

Distribution in northeastern Brazil
Ceará and Maranhão.

Notes
First record from the state of Maranhão.