Belostoma horvathi Montandon, 1903

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 : 41-42

Belostoma horvathi Montandon, 1903

( Figs 11E–I ; 19C ; 24A )

Belostoma horvathi Montandon, 1903b: 359 .

Belostoma oxyurum: Nieser & Melo 1997: 60 (not Dufour).

Belostoma sanctulum: Ribeiro et al. 1998 [in part]: 118 (not Montandon).

Types.— Belostoma horvathi was described based on a female holotype (Santa Catarina) deposited in HNHM [not examined] .

Material examined.— BRAZIL. Goiás — 2 f ( MNRJ 160): Rio Verde, IV.1986, (J. C. M. Carvalho), J. R. I. Ribeiro det. 1999. 1 f ( MNRJ 162): Rio Verde, IV.1986, (J. C. M. Carvalho), J. R. I. Ribeiro det. Minas Gerais — *1 f ( MNRJ 163): Barra de Paraopeba, [without date], ( V. Souza), J. A. de Carlo det. as B. candidulum, J. R. I. Ribeiro det. 1999. * 1 m / 1 f ( MNRJ 168): Barra de Paraopeba, [without date], ( V. Souza), J. A. de Carlo det. * 1 m ( DPIC 1641): Lagoa Santa, [without date and collector], A. L. Melo det. as B. oxyurum . 3 f ( DPIC 492): Pedro Leopoldo, Lagoa dos Mares, 13.XI.1992, (M. H. Pereira), N. Nieser det. as B. oxyurum . * 1 m / 1 f ( DPIC 1218): Viçosa, “Campus da UFV”, 29.III.1994, (M. H. Pereira), N. Nieser det. as B. oxyurum . Paraná — 1 m ( MNRJ 123): Bituruna, 1963, ([?] Staviarski), J. R. I. Ribeiro det. 1999. Rio de Janeiro — * 1 m ( DZRJ 18): Maricá, Restinga de Maricá, 18.X.1996, (J. R. I. Ribeiro), J. R. I. Ribeiro det. 1999. * 1 m (DZRJ- a 308): same, 16. V.1996, (J. R. I. Ribeiro), J. R. I. Ribeiro det. 1999. * 1 m [with eggs on dorsum] (DZRJ-a 78): same, [marsh area], 31.I.1996, (J. R. I. Ribeiro), J. R. I. Ribeiro det. 1999. Santa Catarina — 1 f ( SEMC): Nova Teutônia, I.1954, (F. Plaumann), A. L. Estévez det. 1985 as B. candidulum, J. R. I. Ribeiro det. 1999. São Paulo — * 1 m ( SEMC 1063): Araçá sic [= Araçaíba], [without date and collector], J. D. Lattin det. 1951 as B. apache, J. R. I. Ribeiro det. 1999, J. R. de la Torre-Bueno collection–“K.U.” *1 f [stripe pattern] ( SEMC 229): Itatiba, [without date and collector], J. D. Lattin det. 1951 as B. apache, J. R. I. Ribeiro det. 1999, J. R. de la Torre-Bueno collection–“K.U.”.

Distribution.— BRAZIL: Goiás ( Ribeiro 2005), Minas Gerais ( De Carlo 1938), Paraná ( Ribeiro 2005), Rio de Janeiro ( Ribeiro 2005), Rio Grande do Sul ( De Carlo 1938) [as “Rio Grande”], Santa Catarina ( De Carlo 1938), São Paulo ( De Carlo 1938). ARGENTINA: Chaco ( De Carlo 1938).

Description.—Measurements (m / f). Total length (from apex of head to apex of hemelytra at rest) 16.5– 18.5 / 14.2–18.5; largest width of body 7.5–8.0 / 6.5–8.0; median length of pronotum 3.04–3.33 / 2.37–3.28; greatest pronotal width 5.40–5.73 / 4.53–5.88.

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

Body elliptical. Length of anteoculus 0.86–1.07 times length of interoculus; length of rostral segment I 0.80–0.94 times length of segment II; anterior frontogenal suture usually longer than posterior frontogenal suture; clypeus reaching ocular line; vertex without longitudinal median carina; posterior interocular width 1.44–1.83 times length of anteoculus, and usually 1.50 times width of eye; eyes rounded and globular. Pronotum without longitudinal median carina; greatest pronotal width 1.70–1.92 times its length; scutellum not reaching nodal line (0.07–0.70 mm), without longitudinal median carina; prosternal keel prominent, truncated at apex ( Fig. 11E–F ). Pilosity not extending along genital operculum, covering about half of connexivum.

Male genitalia ( Fig. 11G–I ).—Dorsal arms parallel or slightly convergent, rounded at apex in dorsal view; ventral diverticulum flattened, weakly circular, without dorsal caudal and ventroapical protuberances in dorsal, lateral, and ventral views; caudal lateral margins of ventral diverticulum convex, not sinuous in ventral view; width of ventral diverticulum about 0.9 times its length in ventral view.

Comparative notes.— Estévez (1996) studied a specimen of B. oxyurum identified by Dufour. This is apparently the single specimen upon which Dufour based his description ( Dufour 1863) and thus is the holotype [not lectotype as indicated by Estévez (1996)]. According to Nieser in litt., this means that B. oxyurum has the ventral connexival pilosity extending along the genital operculum and that the interpretation of B. oxyurum in Nieser and Melo (1997) is incorrect. Nieser and Melo’s B. oxyurum specimens, in which the pilos- ity does not extend along the genital operculum, are therefore determined here to be B. horvathi .

Many specimens in the Lattin collection studied here were identified as B. minor (labeled as B. apache ) with the same general facies corresponding to my understanding of B. horvathi . Moreover, Lanzer-de-Souza (1980) believed some B. apache specimens reported from Espírito Santo to be B. minor . In light of this, plus the fact that B. minor is known only from the Greater Antilles, I believe all Lanzer-de-Souza’s B. minor specimens are in fact B. horvathi , and I therefore consider that records of this species from Espírito Santo, to be erroneous.

Based on Estévez (1996), B. minor can be readily distinguished from the other B. oxyurum group species by the sulcus pilosity which extends along the lorum in B. minor . Belostoma oxyurum specimens do, however, resemble B. minor ones in having connexivum pilosity extending along the genital operculum.

According to De Carlo (1938, 1956) and Schnack (1973, 1976), B. horvathi may be recognized by the greatest pronotal width twice its length. Different ratios reported here in B. horvathi specimens (greatest pronotal width 1.70–1.92 times its length) as well as reported in specimens identified by Nieser and Melo [treated as B. oxyurum , see above] ( Nieser & Melo 1997) suggests the possibility of imprecise measurements.

According to De Carlo (1960), B. horvathi can be readily distinguished from all other Belostoma species by the form of the gula, which is posteriorly globular. However, I have found this “distinctive” structural feature to be slight and well within the range of variation found within other species of Belostoma . Based on Montandon (1903b) and Nieser and Melo (1997), B. horvathi can be readily distinguished from the remaining species of the B. oxyurum group by the prosternal keel with tubercles. However, this structural characteristic too is slight and well within the range of variation within this species.

De Carlo (1956) stated that B. horvathi is superficially similar to B. candidulum but can be distinguished by the shape of body and by the greatest pronotal width, which is twice its length. This ratio, however, represents, according to the specimens studied here, imprecise measurments. According to Menke and Lauck (1962), the forms of the phallus and of the body suggest a close relationship between B. horvathi and B. machrisi . However, I have not found such similarities (compare Fig. 11G–I with descriptions in Menke and Lauck [1962] of the B. machrisi phallus). Belostoma horvathi is similar to B. candidulum but may be separated immediately by the dorsal arms of ventral diverticulum, which are parallel or convergent ( Fig. 11G–I ). In B. candidulum , by contrast, the dorsal arms are divergent ( Fig. 11B–D ).

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 19. Dorsal habitus. 19A, Belostoma elongatum Montandon, 1908: specimen from State of Mato Grosso (MNRJ 96). 19B, B. foveolatum (Mayr, 1863): specimen from State of São Paulo (MNRJ 85). 19C, B. horvathi Montandon, 1903: specimen from State of Rio de Janeiro (DZRJ 18). 19D, B. micantulum (Stål, 1860): specimen from State of Amazonas (INPA 0021057). Scale bar: 5.00 mm.

FIGURE 24. Geographic distribution map of Belostoma species in southeastern Brazil. 24A, = B. foveolatum, = B. horvathi. 24B, = B. plebejum, = B. ribeiroi, = B. sanctulum.