Brontostoma rubrovenosum ( Stål, 1860 ), Gil-Santana et al., 2013

Gil-Santana, Hélcio R. & Carpintero, Diego L., 2019, Brontostoma lilloi Carpintero, 1980, a junior synonym of B. rubrovenosum (Stål, 1860) (Hemiptera: Heteroptera: Reduviidae), Zootaxa 4614 (1), pp. 180-186 : 182-184

Brontostoma rubrovenosum ( Stål, 1860)

Ectrichodia rubro-venosa Stål (1860: 72) (description).

Mindarus rubro-venosus: Stål (1872: 101) (checklist).

Ectrichodia rubrovenosa: Walker (1873: 59) (catalog).

Mindarus rubrovenosus: Lethierry & Severin (1896: 134) (catalog).

Brontostoma rubrovenosum: Wygodzinsky (1949: 22) (catalog), Maldonado (1990: 30) (catalog), Dougherty (1995: 203) (citation, geographical distribution), Gil-Santana et al. (2004: 127) (citation), Gil-Santana et al. (2005: 78) (citation), Gil-Santana et al. (2013: 62, 63, 64) (citation, type material, discussion about synonym). ( Brontostoma rubrovenosum in Wygodzinsky (1951: 41 , 52), Carpintero (1980: 10) (as rubrovenosus ), Gil-Santana et al. (2004: 128) and Gil-Santana et al. (2005: 80) are misidentifications and pertain to B. trux (Stål, 1859)) .

Brontostoma lilloi Carpintero (1980: 10 , 32) (description; dorsal view of the head, schematic drawing), Maldonado (1990: 29) (catalog), Dougherty (1995: 203) (citation, geographical distribution), Bachmann (1999: 215) (catalog of types deposited in MACN), Gil-Santana et al. (2004: 127) (citation), Gil-Santana et al. (2005: 78) (citation). New subjective synonym.

Distribution. Bolivia, Brazil, and Argentina.

Remarks. The general structure and the overall coloration of Brontostoma rubrovenosum and B. lilloi , syn. nov. ( Stål 1860, Carpintero 1980), as observed by examination of their types ( Figs. 5–6 , 8–9 ), present enough similarities to con- sider them as belonging to the same species, and therefore, the latter as a junior synonym of the former species. However, differences between their types deserve some comments.

While the total length of the female syntype of B. rubrovenosum is 28 mm ( Stål 1860), the male holotype of B. lilloi is approximately 24 mm. The eyes and ocelli of the female syntype of B. rubrovenosum ( Figs. 5–6 ) are slightly smaller; its fore femora are somewhat thicker; the blackish markings of the femorotibial joints and apices of tibiae are more extensive; the linear reddish markings of the corium are more extensive; the latero-dorsal margin of the connexivum is more extensively marked with yellow; and the general shape and size of the submedian pairs of pale markings of sternites III–VII are slightly different and more extensive than in the holotype of B. lilloi . Nevertheless, taking into account that similar or analogous differences have been recorded as part of intraspecific variation, including sexual dimorphism, in other species of various ectrichodiine genera, particularly among Brontostoma and Pothea ( Wygodzinsky 1951, Dougherty 1995, Gil- Santana & Baena 2009, Gil-Santana et al. 2013, Gil-Santana 2014), they are regarded here as such.

Besides the sexual dimorphism in size of the eyes, ocelli and fore femora, recorded in Ectrichodiinae in general ( Dougherty 1995), it is noteworthy that a similar variation in the reddish markings of the corium of hemelytra were recorded in B. trux ( Gil-Santana et al. 2013) (see e.g. Figs. 1, 3 ) and Pothea furtadoi Gil-Santana & Costa, 2005 ( Gil-Santana 2014), while other variations of the markings on this same region and in the dark markings of the legs were recorded in the aforementioned species and in several other species of Brontostoma ( Wygodzinsky 1951, Gil-Santana & Baena 2009, Gil-Santana et al. 2013), P. berengeri Gil-Santana, 2014 and P. jaguaris ( Carpintero, 1980) ( Gil-Santana 2014) . Color variation of the connexivum of B. doughertyae Gil-Santana et al., 2005 was recorded by Gil-Santana & Baena (2009), whilst a considerable range of variation in the markings of the abdominal sternites was recorded in different species of Brontostoma and Pothea ( Wygodzinsky 1951, Gil-Santana 2014). The significant intraspecific variation in related ectrichodiine species strongly suggest that similar or analogous differences between the syntype of B. rubrovenosum and the holotype of B. lilloi have no taxonomic value.

Both Brontostoma rubrovenosum ( Figs. 5–7 ) and B. alboannulatum ( Stål, 1860) ( Figs. 12–14 ) were described based on females from Rio de Janeiro ( Stål 1860). Stål (1860: 72) himself suspected that B. alboannulatum might be a variety of B. rubrovenosum (“ An varietas praecedentis.?”). Indeed, most of the color differences between the syntypes of the two species ( Stål 1860; Figs. 5–6 , 12–13 ) would be very likely intraspecific variations, similarly as commented above, therefore B. alboannulatum is most probably also conspecific with B. rubrovenosum ( Gil-Santana et al. 2013) . Even the shorter hemelytra of the female type of B. alboannulatum ( Fig. 12 ) would not be contrary of such an assertion, since continuous wing reduction ranging from submacropterous to apterous is common in females of many species of Ectrichodiinae ( Dougherty 1995) . However, the abdominal sternites of the type of B. alboannulatum are completely blackish ( Fig. 13 ), without the submedian pair of pale markings recorded in B. rubrovenosum ( Figs. 6 , 9 ). In spite of the observation of Wygodzinsky (1951), who recorded that in some specimens of Brontostoma colossus (Distant, 1902) the pale markings on the sternites were absent in very darkened specimens, because of the extreme range of variation observed in this species they can otherwise represent more than one species ( Gil-Santana et al. 2013). On the other hand, there is not a well documented variation within the same species of Brontostoma which includes specimens with unicolorous sternites (e.g., entirely blackish as in B. doughertyae ) and others with distinct markings. There is the possibility that the sternites could have become entirely darkened because of some chemical alteration along time. It would be in accordance to the observation of Wygodzinsky (1951) that the pale markings were absent in very darkened specimens of B. colossus , in which such a chemical alteration could also have happened and modified the other parts of the body of the insect. But, in the case of the type of B. alboannulatum , the coloration of the remaining parts of the specimen are so bright (generally reddish in head and thorax and yellowish in lateral margin of connexivum) ( Figs. 12–13 ) as in other specimens examined here. Therefore, due to the uncertainty of the significance of the difference observed in the coloration of the sternites, we do not propose a synonym of the two species at this time, but stress that the taxonomic status of the two nominal species is in need to be better evaluated through further studies.

Figures

FIGURES 5–7. Brontostoma rubrovenosum (Stål, 1860), female type deposited in NRM, catalog number NHRS-GULI000000177, 5, dorsal view, 6, ventral view, 7, labels (5–6 photographed by Gunvi Lindberg, 7 by Bert Gustafsson, © 2018 and 2006 Naturhistoriska riksmuseet). Made available by the Swedish Museum of Natural History under Creative Commons Attribution 4.0 International Public License, CC-BY 4.0, https://creativecommons.org/licenses/by/4.0/legalcode.

FIGURES 8–11. Brontostoma lilloi Carpintero, 1980, syn. nov., male holotype deposited in MACN, 8–9, scale bar 5.0 mm, 8, dorsal view, 9, ventral view (courtesy of Lic. Sebastián de Biase), 10, parts glued to plastics boards and pinned separately, A, dissected genitalia, B, antenna, 11, labels.

FIGURES 1–4. Brontostoma trux (Stål, 1859), syntypes deposited in ZMHB, 1–2, male, 1, dorsal view, 2, labels, 3–4, female, 3, dorsal view, 4, labels.

FIGURES 12–14. Brontostoma alboannulatum (Stål, 1860), female type deposited in NRM, catalog number NHRS-GULI000000176, 12, dorsal view, 13 ventral view, 14, labels (12–13 photographed by Gunvi Lindberg, 14 by Bert Gustafsson, © 2018 and 2006 Naturhistoriska riksmuseet). Made available by the Swedish Museum of Natural History under Creative Commons Attribution 4.0 International Public License, CC-BY 4.0, https://creativecommons.org/licenses/by/4.0/legalcode.