Hydrometra ruschii Cordeiro, Rodrigues & Moreira, 2023

Rodrigues, Juliana Mourão Dos Santos, Cordeiro, Isabelle Da Rocha Silva, Floriano, Carla Fernanda Burguez, Paiva, Nathália De Oliveira, Magalhães, Oséias Martins, Júnior, Evaldo Alves Joaquim, Martins, Thaynara De Souza, Silva, Rafaella Cardoso Da, Siqueira, Gabriel Vieira, Salles, Frederico Falcão, Viala, Séverine, Khila, Abderrahman & Moreira, Felipe Ferraz Figueiredo, 2023, Descriptions of new species and new records of water bugs (Hemiptera: Heteroptera: Gerromorpha & Nepomorpha) from southeastern Brazil, Zootaxa 5393 (1), pp. 1-86 : 38-42

Hydrometra ruschii Cordeiro, Rodrigues & Moreira , sp. nov.

Figs. 5C, E , 26–29

Material examined. Holotype. BRAZIL — Espírito Santo • Santa Teresa, Reserva Biológica Augusto Ruschi , stream; alt. 834 m; −19.8967, −40.5236; 22.VI.2022; JC Santos, JMS Rodrigues, NO Paiva, N Nery, CL Rodrigues leg.; 1 male, CEIOC 82254 . Paratypes. BRAZIL — Espírito Santo • Santa Teresa, Reserva Biológica Augusto Ruschi , stream; alt. 834 m; −19.8967, −40.5236; 22. VI.2022; JC Santos, JMS Rodrigues, NO Paiva, N Nery, CL Rodrigues leg.; 1 female, CEIOC 82255 • Santa Teresa, Reserva Biológica Augusto Ruschi, stream near the headquarter; alt. 838 m; −19.9111, −40.5544; 22. VI.2022; JC Santos, JMS Rodrigues, NO Paiva, L Nery, CL Rodrigues leg.; 2 males, CEIOC 82256 .

Description. Micropterous male. Holotype (Paratypes). BL 11.70 [without segment VIII] (11.80–11.95); HL 3.80 (3.80–3.95); ANTL 2.50 (2.50–2.60); POSTL 1.10 (1.05–1.10); ANTWmax 0.40 (0.40–0.44); ANTWmin 0.20 (0.20); POSTWmax 0.40 (0.35–0.38); POSTWmin 0.25 (0.25–0.28); CLL 0.16 (0.14); CLWmax 0.14 (0.14), MPL 0.18 (0.20–0.22); HW 0.50 (0.48–0.50); IOW 0.12 (0.10–0.12); OL 0.28 (0.28–0.30); EYE 0.20 (0.18–0.20); ANT: I 0.65 (0.64–0.70), II 1.30 (1.25–1.26), III 2.10 (4.10–4.20), IV missing (2.20–2.30); LBL: I–II covered, III 2.00 (2.00), IV 0.30 (0.30); PL 1.70 (1.70); PW 0.60 (0.60); WiL 0.70 (0.60); WiW 0.08 (0.06–0.10); DIST1 1.10 (1.10–1.20); DIST2 1.75 (1.70–1.80); FORELEG, FEM 4.00 (4.00–4.20); TIB 4.70 (4.60–4.70); TAR: I 0.06 (0.06– 0.08), TAR II 0.30 (0.28–0.30), TAR III 0.24 (0.22–0.24); MIDLEG, FEM 4.50 (4.40–4.80); TIB 4.90 (4.90–5.60); TAR: I 0.06 (0.08), II 0.34 (0.32–0.34), III 0.24 (0.22–0.24); HINDLEG, FEM 5.20 (5.20–5.60); TIB 6.80 (6.40); TAR: I 0.06 (0.07–0.10), II 0.34 (0.28), III 0.26 (0.24–0.26); ABL 4.20 [without segment VIII] (4.90); ABWmax 0.50 (0.50); ABWmin 0.40 (0.40); TERL: I covered, II 0.80 (0.70–0.80), III 0.80 (0.85–0.90), IV 0.80 (0.80–0.85), V 0.80 (0.80), VI 0.70 (0.70), VII 0.60 (0.60); TERW: I covered, II 0.20 (0.20), III 0.22 (0.20–0.22), IV 0.22 (0.22– 0.25), V 0.22 (0.22–0.25), VI 0.22 (0.20–0.22), VII 0.30 (0.25–0.27); SVIII 0.56 (0.50–0.52); PP 0.04 (0.04–0.06).

Body brown to dark-brown; whitish longitudinal stripe laterally on thorax and abdomen ( Fig. 26A–C ). Clypeus, antennal tubercles antennomeres I and II, bucculae and maxillary plate dark-brown. Antennomeres III and IV, and labium brown. Eye dark-brown. Legs brown; coxae and venter of trochanters yellow. Venter of head, thorax and abdomen reddish-brown.

Head elongated; apex of anteocular region swollen; anteocular region 2.3 times longer than postocular region; region around eyes slightly swollen, giving impression of a small groove on interocular space; posterior pair of trichobothria reaching anterior margin of pronotum. Clypeus broad; lateral margins constricted basally; anterior margin rounded ( Fig. 26D ). Anterior margin of maxillary plate truncated. Buccula rounded, covering base of labium. Eye well-developed, set on posterior 1/3 of head ( Fig. 26A, B, E ). Antenniferous tubercle with a small V-shaped emargination on anterior margin.Antennomere I shortest, densely covered by short setae; III longest. Labium reaching postocular region of head. Venter of head swollen around eyes, with few setae.

Dorsum of thorax almost completely devoid of punctations, with only a very weak row on pronotal collar (only visible in lateral view in wet specimen); pro- and mesoacetabula each with one large pit anteriorly and another one posteriorly, without smaller circular punctations; metacetabula without large pits or smaller punctations ( Fig. 26C ). Forewing reduced, reaching half of metathorax. Mesoacetabulum set closer to fore- than to metacetabulum. Legs long, slender. Venter of thorax without carinae, tubercles or grooves.

Abdomen obliquely oriented dorsally on segments III–VII, becoming parallel to body on segment VIII. Abdominal mediotergites II–VI longer than broad, with glabrous shiny aspect and striated median portion; mediotergite VII trapezoidal, opaque, with setae, except for glabrous shiny circular area anteriorly. Abdominal laterotergites slightly elevated. Abdominal sternum VI slightly grooved centrally; posteriorly with a pair of tufts of mesally directed setae; abdominal sternum VII constricted ventrolaterally, joined mesally by a wide transverse ridge without projections ( Fig. 26F–H ). Abdominal segment VIII cylindrical, slightly constricted ventrolaterally; posterodorsal margin slightly expanded laterally; posterodorsal process short, straight, with approximately 5% of total length of segment ( Figs. 26F–H , 27A–C ). Pygophore with rounded apex; V-shaped emargination on lateral margin with a few dark setae ( Fig. 27D, E ). Proctiger with rounded apex, without lateral projections ( Fig. 27F ).

Micropterous female. Paratype. BL 12.30; HL 3.85; ANTL 2.45 ; POSTL 1.10 ; ANTWmax 0.50; ANTWmin 0.20; POSTWmax 0.45; POSTWmin 0.30; CCL 0.18; CLWmax 0.16; MPL 0.14; HW 0.52; IOW 0.12; OL 0.30; EYE 0.20; ANT: I 0.70, II 1.25 , III 3.90 , IV 2.20 ; LBL: I– II covered, III 2.50 , IV 0.30; PL 1.75 ; PW 0.60; WiL 0.80; WiW 0.10; DIST1 1.20; DIST2 1.75; FORELEG, FEM 4.20; TIB 4.60; TAR: I 0.08, II 0.34, III 0.22; MIDLEG, FEM 4.50; TIB 4.90; TAR: I 0.08, II 0.38, III 0.24; HINDLEG, FEM 5.60; TIB 6.80; TAR: I 0.08, II 0.34, III 0.24; ABL 5.40; ABWmax 0.90; ABWmin 0.50; TERL: I covered, II 0.90, III 0.90, IV 0.90, V 0.90, VI 0.80, VII 0.60; TERW: I covered, II 0.20, III 0.22, IV 0.25, V 0.22, VI 0.22, VII 0.30; SVIII 0.44; PP 0.14.

General color brown; head with dark-brown portion on anteocular region. Maxillary plate and article III of labium light-brown. Coxae and trochanters whitish yellow ventrally. Abdominal laterotergites II–VII with longitudinal yellow stripe. Abdominal sterna II–VI with dark-brown median stripe; sternum VII anteriorly with submedian pair of circular yellow spots ( Fig. 28C ).

Similar to male in structure, except for the following: pronotum with very weak sparse punctations on collar and posterior lobe (only visible in wet specimen); abdomen less strongly oriented dorsally from segment IV to VII ( Fig. 28B ); abdominal segment VIII triangular, with posterior portion (including posterior process) shiny; posterior process with approximately 30% of total length of segment ( Fig. 28A–C ).

Etymology. This new species is named in honor of Augusto Ruschi (1915–1986), a naturalist who has been essential for the creation of the biological reserve (also named in his honor) where it was collected.

Comments. Hydrometra ruschii Cordeiro, Rodrigues & Moreira , sp. nov. can be distinguished from its South American congeners by the following combination of characteristics: clypeus broad, with lateral margins constricted basally and anterior margin rounded ( Fig. 26D ); dorsum of thorax almost completely devoid of punctations; pro- and mesoacetabula each with one large pit anteriorly and another one posteriorly, without smaller circular punctations ( Fig. 26C ); metacetabula without large pits or smaller punctations ( Fig. 26C ); male abdominal sternum VI slightly grooved centrally, posteriorly with a pair of tufts of mesally directed setae ( Fig. 26F–H ); male abdominal sternum VII constricted ventrolaterally, joined mesally by a wide transverse ridge without projections ( Fig. 26F–H ); male abdominal segment VIII cylindrical, slightly constricted ventrolaterally, with the posterior margin slightly expanded laterally and the posterior process short, straight, with approximately 5% of the total length of the segment ( Figs. 26F–H , 27A–C ); and male pygophore with rounded apex and a lateral V-shaped emargination bearing a few dark setae ( Fig. 27D, E ).

This new species is similar in general aspect to H. guianana Hungerford & Evans, 1934 . They share the dark body with a whitish longitudinal stripe along the sides of the thorax and abdomen, and the male abdominal mediotergite VII with a glabrous, shiny, circular area anteriorly. Differently from the new species, however, H. guianana has the clypeus curved upwards near the apex and with an angulose median projection at the anterior margin ( Nieser 1970: fig 187), bears punctations on the dorsum of the thorax and on all acetabula ( Nieser 1970: fig. 188), and displays completely different modifications of the male abdomen (compare Fig. 26F– H and Hungerford & Evans 1934: plate X). The same aspects shared between the new species and H. guianana are also present in H. fruhstorferi , except for the glabrous, shiny area on male abdominal mediotergite VII. Unlike the new species, however, H. fruhstorferi has the anterior margin of the clypeus obtusely pointed, bears numerous punctations on the dorsum of the thorax and on all acetabula, and has different modifications of the male abdomen (compare Fig. 26F– H and Hungerford & Evans 1934: plate X).

Figures

FIGURE 5. Collecting localities in Espírito Santo state, Brazil. A, B. Reserva Biológica (REBIO) Augusto Ruschi, Piraquê- Açu River; −19.8805, −40.5405. C. REBIO Augusto Ruschi, stream near the headquarter; −19.9111, −40.5544. D, E. REBIO Augusto Ruschi, −19.8967, −40.5236. D. Weir. E. Stream. F. Monumento Natural dos Pontões Capixabas, Sítio Santa Maria, weir; −19.1765, −40.7844. G. Reserva Biológica de Sooretama, puddle on the mud; −18.9704, −40.1168. H. Colatina, Pancas River; −19.2986, −40.7176. I. Floresta Nacional de Goytacazes, tributary paleo-riverbed of Doce River; −19.4376, −40.0768.

FIGURE 26. Hydrometra ruschii Cordeiro, Rodrigues & Moreira, sp. nov., micropterous male, holotype. A. Habitus, dorsal view. B. Habitus, lateral view. C. Thorax and part of the legs, lateral view. D. Apex of head and antennomere I, dorsal view. E. Habitus, ventral view. F−H. Apex of abdomen. F. Ventral view. G. Lateral view. H. Ventrolateral view. Scale bars: 2.0 mm (A, B, E), 1.0 mm (C), 0.5 mm (F, G, H), 0.2 mm (D).

FIGURE 27. Hydrometra ruschii Cordeiro, Rodrigues & Moreira, sp. nov., male terminalia. A−C. Abdominal segment VIII, dorsal, ventral and lateral views, respectively. D, E. Genital capsule, lateral and dorsal views, respectively. F. Proctiger, dorsal view. Scale bars: 0.2 mm (A−D), 0.1 mm (E, F).

FIGURE 28. Hydrometra ruschii Cordeiro, Rodrigues & Moreira, sp. nov., micropterous female, paratype, habitus. A. Dorsal view. B. Lateral view. C. Ventral view. Scale bars: 2 mm.

FIGURE 29. Distribution of Hydrometra ruschii Cordeiro, Rodrigues & Moreira, sp. nov.