Belostoma dilatatum ( 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 : 32-34

Belostoma dilatatum ( Dufour, 1863)

( Figs 9 ; 18B–C ; 23B )

Zaitha dilatata Dufour, 1863: 387 .

Belostoma dilatatum: Montandon apud Lauck (1963): 537.

Belostoma dentatum: De Carlo 1930: 109 , plate VI ( Fig. 17 ) (not Mayr).

Belostoma ripicolum Lanzer-de-Souza, 1992: 147. Syn. n. [as B. ripicola sic, this is a “incorrect original spelling”. See below].

Types.— Belostoma dilatatum was described based on specimens which have been lost; Lauck (1963) proposed a male neotype ( Villa Rica , Department of Guairá, Paraguay) deposited in SEMC [not examined] .

Material examined.— ARGENTINA. 1 f ( MNRJ 101): [without a more precise locality and date], (E. Rios), J. A. de Carlo det. * 1 m / 1 f ( DPIC 208): Corrientes, San Roque, [without date], (C. E. Borda), A. L. Melo det., [at light]. BRAZIL. Mato Grosso — 2 f ( MNRJ 88): Cáceres, 02.XII.1955, (M. Alvarenga), J. A. de Carlo det. Mato Grosso do Sul — * 2 m / 1 f ( DZRJ 1): Corumbá, Popular Nova, 06.II.1997, (J. R. I. Ribeiro), J. R. I. Ribeiro det. 1998. 8 m / 29 f ( MNRJ 87): Salobra, I.1955, (“Comissão I. O. Cruz”), J. A. de Carlo det. 1 f ( MNRJ 102): same, III.1940, (“Comissão I. O. Cruz”), J. A. de Carlo det. Minas Gerais — *1 f ( DPIC 1674): Jaíba, Mocambinho [“casa de bomba”], 10.I.1997, (J. E. Silva), A. L. Melo det. Pará— *1 f ( MZSP): Coraci [15 km NO.], Canindé, Gurupi River, IV.1963, (B. Malkin), J. R. I. Ribeiro det. 1999. Paraíba — * 1 m ( INPA 0020868): João Pessoa, VII.1977, ( V. Daniel [?]), J. R. I. Ribeiro det. 1999. São Paulo — *1 f ( MZSP): Ribeirão Preto, “Fac. Medicina”, XI.1954, (M. P. Barretto), J. R. I. Ribeiro det. 1999, [M. P. Barretto’s collection (1969)]. Rio Grande do Sul — 1 m ( MCNZ 135355): Capão da Canoa, Lagoa dos Quadros, 18.II.1992, (M. E. Lanzer-de-Souza), M. E. Lanzer-de-Souza det. as B. ripicola sic, J. R. I. Ribeiro det. 2004, B. ripicolum holotype. 1 m ( MCNZ 135356): same, B. ripicolum paratype.

Distribution.— ARGENTINA: Alrededores de Quilmes ( Lauck 1963), Buenos Aires ( De Carlo 1938), Córdoba ( Lauck 1963), Corrientes ( De Carlo 1938), Entre Ríos ( De Carlo 1938), La Granja, Mendoza ( Lauck 1963), Quilmes ( Schnack 1976), San Miguel de Tucumán, Santa Fe ( Lauck 1963), Santo Tomé ( De Carlo 1938), Tucumán ( Lauck 1963). BOLIVIA: Santa Cruz ( Lauck 1963). BRAZIL: Mato Grosso ( Ribeiro 2005), Mato Grosso do Sul, Minas Gerais ( Ribeiro 2005), Pará ( Ribeiro 2005), Paraíba ( Ribeiro 2005), Amazonas River [?] ( Mayr 1871), Rio de Janeiro ( Ribeiro 2005), Rio Grande do Sul ( Lanzer 1976), São Paulo ( Ribeiro 2005). PARAGUAY: Guairá ( Lauck 1963). URUGUAY: Artigas ( Ruffinelli & Pirán 1959), Montevideo ( Ruffinelli & Pirán 1959), Paysandú ( Lauck 1963), Treinta y Tres ( Ruffinelli & Pirán 1959).

Description.—Measurements (m / f). Total length (from apex of head to apex of hemelytra at rest) 40.4– 49.0 / 44.5–51.4; largest width of body 18.5–24.7 / 21.5–25.3; median length of pronotum 6.57–8.00 / 7.20– 8.48; greatest pronotal width 12.16–15.20 / 14.40–16.80.

General coloration dark brown. Body elliptical. Length of anteoculus 1.35–1.73 times length of interoculus; length of rostral segment I 0.96–1.07 times length of segment II; anterior frontogenal suture equal to or longer than posterior frontogenal suture; clypeus not reaching ocular line (0.72–1.00 mm); vertex without longitudinal median carina; posterior interocular width 0.82–1.02 times length of anteoculus, and 1.52–1.81 times width of eye; eyes triangular. Pronotum without longitudinal median carina; greatest pronotal width 1.78–2.00 times its length; scutellum occasionally reaching nodal line (0–0.80 mm), usually with longitudinal median carina; prosternal keel not prominent, somewhat rounded at apex ( Fig. 9A–B ). Pilosity extending along genital operculum, usually covering entire margin of connexivum.

Male genitalia ( Fig. 9D–F ).—Dorsal arms anteriorly broad, narrowing gradually toward apex in dorsal view; ventral diverticulum without dorsal caudal protuberance in dorsal and lateral views, and without distinct ventroapical protuberance in lateral and ventral views; brownish heart-shaped figure ( HEF) on ventroapical protuberance in ventral view; caudal lateral margins of ventral diverticulum convex, not sinuous in ventral view; width of ventral diverticulum about 1.3 times its length in ventral view.

Variation.—Specimens collected in Mato Grosso and Mato Grosso do Sul, are less dilated and have a truncated and rectangular prosternal keel ( Fig. 9C ). Moreover, the phallus of these specimens has dorsal arms slightly shorter ( Fig. 9G–I ).

Remarks.—According to article 32.5 of the Code ( Iczn 1999), if there is an “incorrect original spelling” [ B. ripicola , see Lanzer-de-Souza (1992: 147)], such as a lapsus calami or a copyist’s or printer’s error, it must be corrected. Thus the correct name of this species is B. ripicolum , because Belostoma is a neuter noun, not a feminine one.

Comparative notes.—As reported here, the specimens from Mato Grosso and Mato Grosso do Sul ( Fig. 18C ) are less dilated and agree with B. ripicolum specimens observed by Lanzer-de-Souza (1992). According to this author, B. ripicolum differs from B. dilatatum in aspects of phallus, in longer rostral segment I, in length of anteoculus: width of eye ratio, and in length of interoculus: width of eye ratio. However, the male genitalia of the specimens from Mato Grosso and Mato Grosso do Sul are identical and agree with those observed in B. ripicolum by Lanzer-de-Souza (1992). Judging from his description and the figures, B. ripicolum is clearly the same species as B. dilatatum . I therefore consider B. ripicolum to be a junior synonym of B. dilatatum .

De Carlo (1938) and Schnack (1976) reported B. dilatatum specimens with the greatest pronotal width twice its median length. There appears to be moderate intraspecific variation in this ratio among different populations of B. dilatatum , as also mentioned by Lauck (1963).

Figures

FIGURE 9. Belostoma dilatatum (Dufour, 1863). 9A–C, Prosternal keel (lateral view): 9A, Specimen from State of Paraíba (INPA 0020868). 9B, Specimen from State of São Paulo (MZSP). 9C, Specimen from State of Mato Grosso do Sul (DZRJ 1). 9D–I, Phallus: 9D–F, Specimen from Corrientes, Argentina (DPIC 208). 9G–I, Specimen from State of Mato Grosso do Sul (DZRJ 1). 9D and 9G, Dorsal views. 9E and 9H, Ventral views. 9F and 9I, Lateral views. Scale bar: 1.00 mm. (HEF) heart-like figure.

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 18. Dorsal habitus. 18A, Belostoma dentatum (Mayr, 1863): [?] (NHMW). 18B, B. dilatatum (Dufour, 1863): specimen from State of São Paulo (MZSP). 18C, B. dilatatum: specimen from State of Mato Grosso do Sul (DZRJ 1). 18D, B. discretum Montandon, 1903: specimen from State of Amazonas (INPA 0020929). Scale bar: 20.00 mm.

FIGURE 23. Geographic distribution map of Belostoma species in southeastern Brazil. 23A, = B. costalimai, = B. cummingsi, = B. dallasi. 23B, = B. dentatum, = B. dilatatum, = B. discretum, = B. elongatum.