Belostoma oxyurum (Dufour, 1863)

Ribeiro, Josė Ricardo Inacio, 2007, A review of the species of Belostoma Latreille, 1807 (Hemiptera: Heteroptera: Belostomatidae) from the four southeastern Brazilian states, Zootaxa 1477 (1), pp. 1-70 : 39-40

Belostoma oxyurum group sensu Lauck, 1962

This group consists of five species, reaching whose lengths range 15.0–20.0 mm. They share the following

characteristics: anterior interocular width about 1.5 times the width of an eye, and ventral diverticulum of

phallus flattened and large.

Belostoma candidulum Montandon, 1903

( Figs 11A–D ; 17A ; 22B )

Belostoma candidulum Montandon, 1903b: 363 .

Belostoma horvathi: De Carlo 1938: 224 (not Montandon).

Belostoma machrisi: Menke & Lauck, 1962: 7 .

Belostoma amici Piza-Jr., 1975 [in part]: 67. Syn. n.

Types.—According to Estévez (1996), B. candidulum was described based on a female holotype and a male paratype (both from Rio Grande do Sul) deposited in NHRS. These specimens have not been examined .

Material examined.— BRAZIL. Goiás — *1 f (MNRJ 125): Rio Verde, IV.1986, (J. C. M. Carvalho), J. R. I. Ribeiro det. 1999, [stripe pattern]. Minas Gerais — * 1 m / 1 f (MNRJ 161): Carmo do Rio Claro, [illegible date], (J. C. M. Carvalho), J. A. de Carlo det. 1 f (DZRJ-a 506): 54 km NO far away from Campina Verde, Paraná river basin, 15.IX.1994, (W. Costa and A. Sarraf), J. R. I. Ribeiro det. 1999. * 1 m / 1 f (MNRJ 168): Barra de Paraopeba, [without date], (V. Souza), J. A. de Carlo det. as B. horvathi, J. R. I. Ribeiro det. 1999. * 1 m / 1 f (MNRJ 169): same, [without date], (V. Souza), J. A. de Carlo det. Rio Grande do Sul — 1 m (SEMC): Erechim, X.1956, (F. Plaumann), A. L. Estévez det. 1985. Santa Catarina — * 31 m / 44 f (SEMC): Nova Teutônia, I.1954, (F. Plaumann), A. L. Estévez det. 1985. 1 m / 1 f (SEMC): same, X.1956, (F. Plaumann), A. L. Estévez det. 1985. 1 m (SEMC): same, [27 º 11’ S, 52 º 23’ W, 300–500 m], X.1956, (F. Plaumann), J. R. I. Ribeiro det. 1999. 6 m / 9 f (SEMC): São Carlos [?], Chapecó River, 10.V.1957, (F. Plaumann), D. R. Lauck det. 1964 as B. machrisi, A. L. Estévez det. 1985. São Paulo — * 2 m / 2 f (SEMC): [without a more precise locality and date], (R. Spitz), D. R. Lauck det. 1959 as B. horvathi, J. R. I. Ribeiro det. 1999. 2 f (SEMC): same, D. W. Craik det. 1 m / 3 f (DEES): Piracicaba, VIII.1974, ([?] Achiel and Abílio [?]), S. de T. Piza-Jr det. as B. amici, J. R. I. Ribeiro det. 1999, B. amici holotype. ARGENTINA. 1 m (MACN 39347): Buenos Aires, Chascomús, [without date], (Daguerre [?]), J. A. de Carlo det.

Distribution.— ARGENTINA: Buenos Aires (new record). BRAZIL: Minas Gerais ( Schnack 1976) [but see Nieser and Melo (1997)], Goiás ( Ribeiro 2005), Rio de Janeiro ( Ribeiro 2005), Rio Grande do Sul ( Montandon 1903b), São Paulo ( Schnack 1976), Santa Catarina ( Estévez 1996). URUGUAY: Artigas ( Ruffinelli & Pirán 1959).

Description.—Measurements (m / f). Total length (from apex of head to apex of hemelytra at rest) 16.5– 19.1 / 15.8–18.7; largest width of body 7.4–8.3 / 7.5–8.4; median length of pronotum 3.04–3.44 / 3.12–3.60; greatest pronotal width 5.20–6.24 / 5.44–6.24.

General coloration dark brown. Vertex, pronotum, scutellum, part of hemelytra occasionally with hyaline longitudinal stripe (see Smith & Smith apud Smith 1976).

Body elliptical. Length of anteoculus 0.88–1 length of interoculus; lengths of rostral segments I and II equal; anterior frontogenal suture shorter, equal to, or longer than posterior frontogenal suture; clypeus reaching ocular line; vertex without longitudinal median carina; posterior interocular width 1.47–1.67 times length of anteoculus, and 1.53–1.92 times width of eye; eyes rounded. Pronotum without longitudinal median carina; greatest pronotal width 1.67–1.82 times its length; scutellum not reaching nodal line (0.16–0.40 mm), without longitudinal median carina; prosternal keel prominent, acute at apex ( Fig. 11A ). Pilosity not extending along genital operculum, covering part of connexivum.

Male genitalia ( Fig. 11B–D ).—Dorsal arms divergent, slightly broader toward apex in dorsal view; ventral diverticulum flattened, relatively broader, more circular, without dorsal caudal protuberance in dorsal and lateral views, and without ventroapical protuberance in lateral and ventral views; caudal lateral margins of ventral diverticulum convex, not sinuous in ventral view; width and length of ventral diverticulum equal in ventral view.

Comparative notes.—According to Nieser and Melo (1997), Schnack (1973, 1976), and here, B. candidulum differs from other species of this group because segments I and II of its rostrum are equal in length. However, according to De Carlo (1938; 1956), Estévez (1996), and Montandon (1903b), rostral segments I and II are subequal. This discrepancy suggests that this character varies in B. candidulum . However, the possibility remains that the discrepancy results from imprecise measuring and is therefore an anomaly (A. L. Melo, pers. comm.).

The synonymy of B. amici with B. candidulum is clear. The type of B. amici possesses all the diagnostic features of B. candidulum . The differences between the types are small and well within the limits of variability found here in B. candidulum . I therefore synonymize B. amici with B. candidulum .

Figures

FIGURE 11. Belostoma candidulum Montandon, 1903, B. horvathi Montandon, 1903, and B. sanctulum Montandon, 1903. B. candidulum. 11A, Prosternal keel (lateral view): specimen from State of São Paulo (SEMC). Scale: 0.50 mm. 11B–D, Phallus: specimen from Chaco, Argentina (MACN 39307). Scale: 1.00 mm. B. horvathi. 11E–F, Prosternal keel (lateral view): 11E, Specimen from State of Minas Gerais (DPIC 1641). 11F, Specimen from State of Minas Gerais (DPIC 1218). 11G–I, Phallus: specimen from State of São Paulo (SEMC 1063). Scale bar: 1.00 mm. B. sanctulum. 11J– K, Prosternal keel (lateral view): 11J, Specimen from State of Espírito Santo (ISNB). 11K, Specimen from State of Rio de Janeiro (DZRJ 17). Scale: 0.50 mm. 11L–N, Phallus: specimen from State of Espírito Santo (ISNB). Scale: 1.00 mm. 11B, 11G and 11L, Dorsal views. 11C, 11H, and 11M, Ventral views. 11D, 11I and 11N, Lateral views. (VED) ventral dilatation.

FIGURE 17. Dorsal habitus. 17A, Belostoma candidulum Montandon, 1903: specimen from State of São Paulo (SEMC). 17B, B. costalimai De Carlo, 1938: specimen from State of Roraima (AMNH). 17C, B. cummingsi De Carlo, 1935: specimen from State of São Paulo (MACN 37791). 17D, B. dallasi De Carlo, 1930: specimen from State of Ceará (DPIC). Scale bar: 5.00 mm.

FIGURE 22. Geographic distribution map of Belostoma species in southeastern Brazil. 22A, = B. anurum, = B. aurivillianum. 22B, = B. bergi, = B. bosqi; = B. candidulum.