Curicta Stål, 1862 (Insecta: Heteroptera: Nepidae) from Maranhão, Brazil

ABSTRACT

The genus Curicta Stål comprises aquatic insects commonly known as water scorpions and typically occurs in habitats associated with marginal mud. It is exclusively distributed in the New World, with 17 species recorded in the Neotropical Region, including 12 in Brazil. In the state of Maranhão, only one species, Curicta montei De Carlo, has been documented to date. Thus, this study aims to explore the diversity of Curicta in the state of Maranhão. A total of 124 specimens were collected, representing three species: Curicta granulosa De Carlo, C. johnpolhemi Keffer, and C. montei. Notably, C. johnpolhemi and C. granulosa are reported here as new distribution records for the state of Maranhão. Previously described based solely on a single female, our investigation of C. johnpolhemi enabled the description of the male, providing additional taxonomic insights for the species. Photographs of one specimen from each species are provided and diagnostic features are illustrated.

Keywords:
Aquatic insects; Diversity; Morphology; Nepomorpha; Water scorpions

Introduction

Nepids (Nepidae) are commonly known as water scorpions, distinguished by the presence of non-retractable respiratory siphons of the eighth abdominal segment (Parsons, 1973). This family comprises two subfamilies: Nepinae, including two tribes (Curictini and Nepini), and Ranatrinae, consisting of three tribes (Austronepini, Goondnomdanepini, and Ranatrini) (Lansbury and Woodward, 1974; Keffer, 2004). Currently, the family includes 268 species distributed globally, with 93 documented in the Neotropical Region and 49 in Brazil (Polhemus and Polhemus, 2008; Moreira et al., 2011; Rodrigues et al., 2012).

The subfamily Nepinae is represented by two genera in the Neotropical Region: Curicta Stål, 1862 (Curictini) and TelmatotrephesStål, 1854 (Nepini) (Keffer, 1997, 2004). Curicta is exclusively distributed in the New World, with 17 species recorded in the Neotropical Region and 12 in Brazil, namely Curicta bilobataKuitert, 1949; C. bonaerensis (Berg, 1879); C. borelliiMontandon, 1903; C. decarloi Keffer, 1997; C. granulosa De Carlo, 1951; C. johnpolhemi Keffer, 2000; C. lenti De Carlo, 1951; C. longimanus De Carlo, 1951; C. montei De Carlo, 1961; C. pelleranoi De Carlo, 1951; C. tibialis (Martin, 1898); C. volxemi (Montandon, 1895) (Keffer, 1997; Moreira et al., 2011). In the state of Maranhão, only a single species, C. montei De Carlo, 1961, has been recorded (Keffer, 1997; Moreira et al., 2011).

Representatives of Curicta demonstrate a preference for muddy waters, utilizing their flattened, dark-colored bodies for effective camouflage in the mud (Sites and Polhemus, 1994). They are also found in shallow waters along the banks of lakes or small streams, often clinging to marginal vegetation (Keffer, 1997).

The state of Maranhão is situated in the tropical region of Brazil, encompassing a transitional area between the Caatinga and Amazon biomes, with an extensive area of Cerrado in the intermediate region. These regions are currently experiencing the impacts of anthropic activities, mainly by monocultures (Schneider et al., 2021). In general, studies on aquatic Heteroptera remain scarce in the state of Maranhão. This knowledge gap is particularly notable for Curicta, given the limited number of recorded species and the absence of comprehensive literature on this group in the region. Consequently, there is a need for taxonomic and ecological studies to address these knowledge gaps concerning these important predatory aquatic insects. Thus, our objective was to investigate the diversity of Curicta species in the state of Maranhão. In this study, we present a comprehensive list of Curicta species found in Maranhão, along with illustrated diagnostic features, supplemental descriptions, and distribution maps. This information aims to contribute significantly to filling the existing gaps in our understanding of aquatic Heteroptera in the region.

Materials and methods

Sampling was conducted at several sites across the state of Maranhão using an aquatic entomological net in a “D” shape with a 1 mm mesh or through active searches among leaves, roots, trunks, macrophytes, and marginal mud (Fig. 1). The collected material was labeled, preserved in bottles with 80% ethyl alcohol, then stored at the Aquatic Entomology Laboratory (LEAq), Universidade Estadual do Maranhão.

Figure 1
Typical habitats where species of Curicta Stål may be found in the state of Maranhão. A– Buriti Corrente stream (Caxias municipality); B– Ourives River (Barra do Corda municipality); C– Mearim tributary (Barra do Corda municipality); D– Pond (Caxias municipality).

The identification, comparison, and morphological terminology of the specimens were based on Keffer (1997, 2000). Body length (measured from the labrum to the tip of segment VII) and pronotal width were measured using a manual caliper with an accuracy of 0.1 mm, and the dimensions are provided in millimeters. Key morphological features, such as the head, profemur, pronotum, carina, and siphon, were photographed using a Stemi DV4 ZEISS stereomicroscope with a DFC420 digital camera, and all measurements are expressed in millimeters. The distribution map was created using QGIS software version 3.28. When citing label data for the examined material, a comma (,) separates different pieces of information, while a semicolon (;) distinguishes information from different samples. All specimens examined here were identified by the first and last author. One representative of each sex of every identified species will be deposited as vouchers in the Coleção Zoológica do Maranhão (CZMA).

Photos of type specimens examined were provided by Dr. Thomas J. Henry (NMNH – National Museum of Natural History, Washington, DC, USA)

Results

We examined a total of 124 specimens of Curicta, comprising three species: Curicta granulosa (23 females and 23 males), C. johnpolhemi (39 females and 31 males), and C. montei (5 females and 3 males). In total, 67 females and 57 males were identified. The following list provides comprehensive information concerning the diagnosis, supplementary description, analyzed material, distribution, and comments for each species.

Class Insecta Linnaeus, 1758

Order Hemiptera Linnaeus, 1758

Suborder Heteroptera Latreille, 1810

Infraorder Nepomorpha Popov, 1968

Family Nepidae Latreille, 1802

Subfamily Nepinae Latreille, 1802

Tribe Curictini Menke & Stange, 1964

Curicta granulosa De Carlo, 1951

Figs. 2A-F, 3

Figure 2
Female of Curicta granulosa De Carlo. A– Habitus, dorsal view; B– Dorsal view of head and pronotum; C– Lateral view of profemur; D– Profemur with profemoral groove and teeth and tubercles; E– Last abdominal segment, lateral view; F– Genitalia of female. Abbreviations: sip=siphon; car= carina; prg= pronotal groove; pro=pronotum; pti= protibia; pfe= profemur; tpg= teeth of profemoral groove; pes= parasternum; VII seg= seventh abdominal segment; gp1=gonapophysis-1; gp2=gonapophysis-2.

Figure 3
Records of Curicta granulosa De Carlo in South America and Brazil, indicating new records in the state of Maranhão.

Curicta granulosa De Carlo, 1951: 411–412 (Original description); Nieser, 1975: 131–133 (New records and key); Keffer, 1997: 177–183 (Redescription, distribution, and key); Moreira et al., 2011: 48–49 (List of species and distribution).

Curicta venezolana De Carlo, 1960: Keffer, 1996: 177 (Synonymy).

Curicta intermedia Martin, 1898: Roback and Nieser, 1974: 40–41(Misidentification).

Diagnosis – This species can be recognized by the following combination of characteristics: distinct carina at apex of head; pronotum densely covered with granules and presence of well-defined profemoral grooves (Fig. 2D) (Keffer, 1997).

Supplemental description – Specimens examined: 23 females and 23 males. Females: Body length, 20.0–25.0 (Fig. 2A); profemur length, 5.6–7.3 (Fig. 2C); siphon, 12.5–20.0. Male: Body length, 18.0–22.0 mm; profemur length, 4.9–6.2; siphon, 7.0–15.0. Female genitalia: Gonapophysis-1 elongate, with dorsal angles more anteriorly than posteriorly curved, well-sclerotized. In lateral view, gonapophysis-1 broadly triangular, nearly reaching length of gonapophysis-2, also well-sclerotized. Gonapophysis-2 dorsoventrally flattened, linear, slightly curved medially, extending posteriorly beyond posterior margin of gonapophysis-1 (Fig. 2F). Male genitalia. Parameres elongate and curved inward apically.

Note – The pronotum of Curicta is often covered with mud or other bottom substrate in its aquatic habitat, which may present challenges in identifying granules on the pronotum of C. granulosa (Fig. 2B). This represents the first records of Curicta granulosa from the state of Maranhão.

Material examined – BRAZIL • 1♂; Maranhão, Aldeias Altas, Limpeza stream, 4°40’33.6” S 43°32’31.2” W, 19 Jan. 2015, G. Silva leg.; • 1♀; same locality, Poção stream, 4°40’26.4” S 43°32’27.6” W, 02 Oct. 2018; •1♂; same collection data as for preceding, 25 Jul. 2022, F. Stefanello leg.; • 1♂; same locality, São Raimundo pond, 4°38’50.7” S 43°28’35.8” W, 10. Oct. 2019; • 1♂, 3♀; Caxias, Ponte stream, 04°52’72.3”S 43°21’89.4”W, Aug.–Sep. 2013/ 24 Nov. 2014; • 1♀; same collection data as for preceding, 21 Jul. 2015, F. Araújo leg.; • 1♂, 1♀, same collection data as for preceding, 27 Aug. 2019; • 3♂; same locality, São José stream, 4°51’18.75” S 43°20’23.92” W, 22. Aug.–Sep. 2013; • 2♂, 1♀; same collection data as for preceding, 01 Jul. 2015, J. Carvalho leg.; • 1♂; same locality, Itapecuru River, 4°49’562” S 43°22’025” W, 07 Jul. 2014; • 1♂; same locality, Primavera stream, 4°50’56.4” S 43°29’42” W, 12 Aug.2022, Stefanello leg.; • 1♂, 1♀; same locality, Riachão stream, 4°56’8.59” S 43°21’26.65” W, 12 Jul. 2015, C.L. Franco leg.; • 2♂; same locality, Guarimã stream, 4°48’48.5” S 43°28’33.2” W, 11 Aug. 2022, F. Stefanello leg.;• 1♂, 3♀; same locality, tributary of Guarimã stream, 4°48’45.4” S 43°29’28.9” W, 11 Aug. 2022, F. Stefanello leg.; • 4♂, 1♀; Barra do Corda, tributary of Mearim River, 5°30’29.5” S 45°19’35.0” W, 31 Oct. 2022, F. Stefanello leg.; • 1♂; same locality, Tributary of River Ourives, 5°44’17.6” S 45°13’47.2” W, 01 Oct. 2022. F. Barros leg.; • 1♂, 1♀; Centro Novo do Maranhão, Gurupi River, 3°30’35.0” S 46°49’35.5” W, 15.X.2022, F. Stefanello leg.; • 6♀; same locality, Itaquitiua stream, 3°31’38.5” S 46°49’28.6” W, 12 Oct.–15 Oct. 2022, F. Stefanello leg.; • 2♀; Duque Bacelar, Araim stream, 4°10’07.0” S 42°59’34.0” W, 14 Jun. 2019; • 1♂; Parnarama, Sussuarana stream, 05°42’20.7” S 43°08’36.1” W, 14 Jul. 2022, F. Stefanello leg.; • 2♂, 2♀, Presidente Dutra, Pezão farm, 05°16’53.8” S 44°28’07.4” W, 15 Jul. 2022, F. Stefanello leg.

Distribution – BRAZIL: Acre (Keffer, 1997), Amazonas (De Carlo, 1951), Pará (Keffer, 1997), Tocantins (Keffer, 1997), Mato Grosso (Keffer, 1997), Rondônia (Keffer, 1997), Bahia (Keffer, 1997), Maranhão (this work), Minas Gerais (Melo and Nieser, 2004), Mato Grosso do Sul (Keffer, 1997), and São Paulo (Keffer, 1997). PARAGUAY (Keffer, 1997). BOLIVIA (Keffer, 1997). PERU (Keffer, 1997). COLOMBIA (Keffer, 1997). VENEZUELA (De Carlo, 1967). Curicta granulosa is the only South American species occurring extensively across the northern half of the continent and throughout the Amazon basin (Keffer, 1997) (Fig. 3).

Curicta johnpolhemi Keffer, 2000

Figs. 4A-F, 5

Figure 4
Curicta johnpolhemi Keffer female (holotype) and male. A– habitus of female, dorsal view; B– habitus of male, dorsal view; C– dorsal view of head and pronotum; D– lateral view of profemur; E– profemur showing profemoral groove and presence of tubercles; F– genitalia of female. Abbreviations: sip=siphon; car=carina; pro=pronotum; pfe= profemur; pti= protibia; pfs– profemoral sulcus; gp1= gonapophysis-1; gp2= gonapophysis-2.

Figure 5
Records of Curicta johnpolhemi Keffer in South America and Brazil, indicating new records in the state of Maranhão.

Curicta johnpolhemi Keffer, 2000, 107: 145–148 (Original description); Moreira et al., 2011: 48–49 (List of species and distribution).

Diagnosis – This species can be recognized by the following characteristics: It is the smallest species within the genus, featuring two profemoral teeth (Fig. 4D), and the prominent carinae on abdominal tergum VII are connected, forming a dome (Fig. 4A–B) (Keffer, 2000).

Supplemental description – Specimens examined: 39 females and 31 males including the holotype: Body length, 16.1; profemur length, 5.0; siphon, 8.5 (Fig. 4A). Additional females: Body length, 16.0–17.3; profemur length, 5.0–6.3; siphon, 8.5–9.5. Female genitalia. Gonapophysis-1 elongate, with dorsal angles formed more anterior than posterior, well-sclerotized. In lateral view, gonapophysis-1 subtriangular, also well-sclerotized. Gonapophysis-2 dorsomedially convex, lanceolate (Fig. 4F), flattened basally, slightly convex medially, projecting posteriorly beyond posterior margin of gonapophysis-1 (Fig. 4F). Description of male (Fig. 4B-E): Body length, 15.0–16.5 (Fig. 4B); length profemur, 5.0–5.8; siphon, 8.0–9.0. Color dark-brown. Head: Eye width 0.3× interocular distance. Vertex broadly convex; without median longitudinal carina. Lobe of antennal segment II less than 0.5× length of segment III. Thorax: Elongate pronotum; lateral length 1.7× posterior width. Lateral margins parallel at middle and diverging posteriorly and anteriorly. Transverse furrow incomplete. Median longitudinal furrow very shallow; obsolete in posterior 2/3. Median longitudinal ribs rounded. Lateral longitudinal furrows shallow. Lateral longitudinal ribs rounded. Granulations on median furrow and humeral lobes. Posteroventral extension of pronotum located on ventral midline at junction of prosternum and mesosternum. Width of scutellum less than its length with indistinct tridentate pattern; longitudinal section of lateral serrations appears convex medially. Procoxa 0.50× profemoral length. Two profemoral teeth (Fig. 4D); distance from base of femur to tip of anteroventral profemoral tooth 0.52× total length of profemoral. Profemur moderately convex beyond profemoral teeth. Single row of cusps in profemoral groove in distal two-thirds, with no teeth in groove distally (Fig. 4E). When extended posteriorly, metafemur extends only to posterior margin of sternum VI. Lateral margins of hemelytra subparallel from apex of scutellum to base of membranes, narrower anteriorly and posteriorly. Metathoracic wings fully developed with Mp and CuA veins converging in posterior third of wing. Prominent carina on bilateral plates of last abdominal tergum (VII), forming a convex arc in distal two-thirds, reaching its highest elevation along midline, and appearing tomentose distally. Abdomen: Parasternum of last segment without distal processes. Posterior margin of operculum extending beyond distal margin of parasternum. Male genitalia: Parameres elongate and curved inward apically.

Note – The species C. johnpolhemi was previously known from only a single female; the holotype was described from the state of Minas Gerais, Brazil. Through the collection of both sexes from various streams and by correlating them with the previously described female, as well as comparing them with the holotype, it became feasible to describe the male.

Material examined – BRAZIL, • 3♂, 10♀; Maranhão, Caxias, Areia Branca stream, APA–Inhamum, 04º53’55.4” S 43º25’24.9” W, 29 Oct. 2011 / 28 Feb. 2012 / 08 Mar. 2013 / 27 Feb. 2014 / 30 Apr. 2014 / 28 May. 2015 / 06 Aug. 2015; • 1♂; same locality, Inhamum stream, 04º53’55” S 43º25’60” W, 02 Nov. 2011, G. Gomes leg., • 1♂, 4♀; same collection data as for preceding, 27 Mar. 2012 / 07 Mar. 2013; • 1♂; same locality, Buriti stream, APA– Buriti do Meio, 4°54’54” S 43°6’46.8” W, 02 Oct. 2017; • 1♂, 1♀; same locality, Lamego stream, 4°49’01.3” S 43°20’38.1” W, 15 Jan. 2015, J. Campos leg.; • 1♀; same locality, Lagoa Merim, APA– Inhamum, 04°53’55.5” S 43°26’25.1” W, 26 Jul. 2013; •1 ♂; same locality, Olarias stream, 04°57’44.4” S 43°07’37.1” W, 04 Oct. 2013; • 1♂, 1♀; Primavera stream, 4°50’56.4” S 43°29’42” W, 12 Aug. 2022; • 2♀; same locality, Riachão stream, 4°56’8.59” S 43°21’26.65” W, 26 Mar. 2012 / 20 Jun. 2013; • 1♀; same locality, Soledade stream, APA–Inhamum, 04°53’28.1” S 43°25’52.3” W, 28 Jul. 2010, D. Gomes leg.; • 1♂; same collection data as for preceding, 28 Jun. 2014; • 2♂, 2♀; same locality, Inhamum stream, 4°53’52.8” S 43°25’58.8” W, 05 Jul. 2011 / 06 Jan. 2012; • 1♂, 3♀; Sumidouro stream, APA–Inhamum, 4°53’24” S 43°25’55.2” W, 29 Jul. 2010 / 10 Oct. 2010; • 1♂, 1♀; same collection data as for preceding, 13 Jul. 2011 / 19 Oct. 2011; • 14♂ and 9♀; 25 Mar. 2012 / 22 Nov. 2013 / 01 Jul. 2014 / 01 Dec. 2014 / 20 Feb. 2015 / 18 Mar. 2015; • 1♂; same collection data as for preceding, 11 May. 2017; • 4♀, 1♂; same collection, Carolina, Mansinha stream, 7°08'07.7” S 47°26'07.3” W, 31 Jan. 2022, C.L. Franco leg; • 1♀; same collection, Codó, Buriti Corrente stream, 4°45’7.2” S 43°39’57.6” W, 18. Aug. 2021; • 1♀; same collection data as for preceding, Baixa Grande stream, 4°45’15.45”S 43°39’20.3”W, 29 Sep. 2022; • 1♀; same collection, Mirador, Riachão stream, 04°56’9.2” S 43°21’26.30” W, 29 Jul. 2018, • 1♂; same collection, São João do Sóter, Pedras stream, 4°58’55.2” S 43°37’33.6” W, 17 Jul. 2015; • 1♂, 1♀; PARNA Nascentes do Parnaíba, Cachoeira grande, Riozinho River, 9°49’12.9” S 46°16’19.2” W, 12 Set. 2023, F. Stefanello, 2023 leg.

Distribution – Brazil: Minas Gerais (Keffer, 2000), Maranhão (this work) (Fig. 5).

Note – This represents the first record of Curicta johnpolhemi outside the type locality and the first records from the state of Maranhão and northeastern Brazil. This species appears to inhabit the Cerrado biome but remains poorly collected in other sites.

Curicta montei De Carlo, 1960

Figs. 6A-F, 7

Figure 6
Female Curicta montei De Carlo. A– habitus, dorsal view; B– dorsal view of head and pronotum; C– lateral view of profemur; D– profemur with profemoral groove and teeth and tubercles; E– genitalia of female. F– Last abdominal segment, lateral view. Abbreviations: sip=siphon; pro=pronotum; pfe= profemur; pti= protibia; tpg= teeth of profemoral groove; gp1=gonapophysis 1; gp2=gonapophysis 2; pes= parasternum; VII seg= seventh abdominal segment.

Figure 7
Records of Curicta montei De Carlo in South America and Brazil, indicating new records in the state of Maranhão.

Curicta montei De Carlo, 1960: 48–49 (Original description); Keffer, 1998: 114 (incorrect synonymy of C. doesburgi with C. montei); Moreira et al., 2011: 48–49 (List of species and distribution).

Curicta doesburgi De Carlo, 1967, (1–4): 33. (1966) (Description); Nieser, 1975: 131–132 (Description); Keffer, 1997: 191–195 (Synonymy, redescription, distribution, and key).

Diagnosis – This species can be distinguished by the following characteristics: the large, thumb–shaped parasternal lobes (Fig. 6E), profemur extending up to 1 mm beyond the lateral length of the pronotum, and the absence of a dark central ring on the protibia (Fig. 6D) (Keffer, 1997).

Supplemental description – Specimens examined: 5 females and 3 males. Females: Body length, 21.0–27.0 (Fig. 6A); profemur length, 6.2–7.9; siphon, 14.0–25.0. Male: Body length, 17.0–23.0; profemur length, 5.6–6.9, siphon, 13.0–18.0. Female genitalia: Gonocoxa-1 elongate, with distinct dorsal angles positioned more anteriorly than posteriorly, well-sclerotized. Gonapophysis-1 triangular in lateral view, tapering from middle to apex, well-sclerotized. Gonapophysis-2 dorsally flattened, needle-shaped, basally flattened throughout its length, extending posteriorly beyond posterior margin of gonapophysis-1 (Fig. 6E). Male genitalia: Parameres elongate and curved inward apically.

Material examined – BRAZIL, •1♂, 1♀; Maranhão, Aldeias Altas, São Raimundo Pond, 4°38’50.7” S 43°28’35.8” W, 03 May. 2015, C.A.S. Azevedo leg.; •1♀; same collection data as for preceding, Limpeza stream, 4°40’33.6” S 43°32’31.2” W, 27 Aug. 2019; • 1♀; same collection data as for preceding, Poção stream, 4°40’26.4” S 43°32’27.6” W, 25 Jul. 2022; • 2♀; Caxias, São José stream, 4°51’18.75” S 43°20’23.92” W, 20 Nov.2013/ 14 May. 2019; • 1♂; same locality, Sanharó stream, 4° 52’1.10” S 43°23’29.17” W, 01 Jul. 2015; • 1♂; São João do Sóter, Pedras stream, 5°07’24.0” S 43°48’45.1” W, 08 Mar. 2016; 1♀; PARNA Nascentes do Parnaíba, Cachoeira grande–riozinho, 9°49’12.9” S 46°16’19.2” W, 12 Sep. 2023, F. Stefanello, 2023 leg.

Distribution – BRAZIL: Maranhão (Keffer, 1997; this work), Ceará (De Carlo, 1960), Pernambuco (Keffer, 1997). VENEZUELA (Keffer, 1997). GUYANA (Keffer, 1997). SURINAME (De Carlo, 1960) (Fig. 7).

Discussion

Spatial distribution of species

Only a single species of Curicta had been documented since Keffer's work in 1997 for the state of Maranhão (C. montei). This study added two new records (C. granulosa and C. johnpolhemi) for the state. Curicta granulosa, known for its widespread presence, is documented in various locations across South America (De Carlo, 1951, 1967; Keffer, 1997; Melo and Nieser, 2004). It is found in virtually all phytogeographic areas of Brazil and exhibits the same distribution pattern in Maranhão, occurring in both the Amazon and Cerrado biomes, including transitional zones in the state (Fig. 3). In contrast, Curicta montei has a limited distribution in northern South America and occurs in Brazil exclusively in the Northeast region of the country (De Carlo, 1960; Keffer, 1997). Its presence extends from the Amazon biome to the northern portion of the Caatinga and Cerrado biomes (Fig. 7).

The geographic distribution of C. johnpolhemi was significantly expanded. Initially recorded only in the state of Minas Gerais, with the holotype as the single record for Brazil. The recent discovery in Maranhão, marking its first occurrence in northeastern Brazil, suggests that this species inhabits intermediate areas of Cerrado between Maranhão and Minas Gerais (Fig. 5). Curicta johnpolhemi in Maranhão primarily inhabits streams in the eastern and southern regions, comprising areas of Cerrado and transition zones. Notably, there is no evidence of the species in the Amazon biome. This underscores the limited knowledge of this group in Brazil and emphasizes the necessity for further studies in the region (Diniz‐Filho et al., 2010).

While this study focuses on a specific region, it makes a significant contribution to addressing Linnean and Wallacean gaps, signifying the limited knowledge regarding species diversity or distribution, particularly in the context of the Curicta fauna in Brazil (Hortal et al., 2015). Surveys of heteropterans, such as those conducted in this study, hold substantial importance, especially in areas experiencing pronounced anthropogenic influence. Understanding the taxonomy and distribution of the species is imperative for developing effective conservation strategies and mitigating the risk of (local) extinction due to human-induced impacts (Lewis, 2006). These surveys play a crucial role in enhancing water quality indices, enabling their employment in monitoring programs, and evaluating the overall integrity of aquatic systems (Ramos et al., 2022).

Comparative morphology

Curicta johnpolhemi shares similarities with other Curicta species from North and Central America, such as C. scorpioStål, 1862 and C. pronotataKuitert, 1949. These species also have conspicuous carinae on the last abdominal tergite, but their carinae are paramedial and, as a result, do not together form a dome-shaped structure. The external morphology of examined males of C. johnpolhemi closely resembles that of females and generally differs only in size, with females tending to be larger than males. Curicta granulosa exhibits a greater resemblance to C. montei, sharing common characters such as profemoral teeth situated generally closer to the distal end than the proximal end; the posterior half of the sternum that lacks distinct expansion; and a parasternum in the last abdominal segment terminating in digitate or thumb-like processes that may or may not extend beyond the posterior margin of the operculum (Keffer, 1997).

It is common in several insect groups to focus on the male terminalia, which generally provide a large number of characters with taxonomic value (Capellari and Amorim, 2009; Moulton, 2017). However, the work conducted by Keffer (1997) showed few significant differences in the male genitalia as well as in the female genitalia, after which these structures lack species-specific characteristics, and species identification is based only on non-reproductive morphological traits. Nevertheless, based on the descriptions of the females and the examination of the female genitalia of the species collected in the state of Maranhão, it was found that there are differences in the conformation of the gonapophyses among species, the structures of which were neglected in the work of Keffer (1997). These structures, therefore, represent useful additional characters for distinguishing Curicta species and can be used for the characterization and identification of species, especially in the absence of the male. Intraspecific variation in the morphology of female terminalia is minor and inconspicuous, limited to the outlines of the structures and not affecting the specific shape of any of the structures analyzed.

Acknowledgments

We would like to thank the Universidade Estadual do Maranhão – Campus Caxias, for the structure offered and the entire team of the Aquatic Entomology Laboratory – Leaq for their support and assistance with the collections. The authors are grateful to Dr. Thomas Henry (Smithsonian National Museum of Natural History) for the photos of type material of Curicta johnpolhemi deposited in the NMNH. The authors are thankful to the reviewers for their valuable comments that significantly improved this manuscript.

• Funding

  This project was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) through the PIBIC Scholarship for Scientific Initiation (#142007/2022-6) to FBSB; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brazil (CAPES) – Financial code 001 for the scholarship for CLF; Fundação de Amparo à Pesquisa e ao Desenvolvimento Científico e Tecnológico do Maranhão (FAPEMA), for the FAPEMA Visiting Professor Scholarship (#BPV-00409/22) for FS; FAPEMA Universal Grant (#01517/18) awarded to CASA.

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Edited by

Associate Editor: Fabio Quinteiro

Publication Dates

• Publication in this collection
  05 Aug 2024
• Date of issue
  2024

History

• Received
  25 Jan 2024
• Accepted
  21 June 2024