Brontostoma infensum Wygodzinsky 1951
Creators: name: Gil-Santana, Hélcio R.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hemiptera
Reduviidae
Brontostoma
Brontostoma infensum

description: Brontostoma infensum Wygodzinsky, 1951
(Figs. 71–83)
Brontostoma infensum Wygodzinsky, 1951: 39, 46, 47–48 (original description, figures).
Brontostoma infensum: Maldonado (1990: 29) (catalog), Dougherty (1995: 203) (citation, geographical distribution), Gil-Santana et al. (2004: 127,128) (citation, key), Gil-Santana et al. (2005: 78, 79) (citation, key), Gil-Santana et al. (2013: 62) (citation).
Distribution. Argentina, Peru?, Brazil? Diagnostic characters and their variability. Male. Body length 28–29 mm.
COLORATION (Figs. 71, 73–74): head; thorax (including scutellum and transverse furrow of pronotum, but excepting hind lobe of pronotum), and legs (except tarsi), generally blackish to dark brown. Base of neck yellowish ventrally; hind lobe of pronotum reddish; stridulitrum pale; hemelytra generally reddish with approximately distal half of clavus and adjacent area on corium blackish; vein between these dark areas also dark in the holotype, but pale reddish in the examined paratype; a longitudinal median dark spot on corium; membrane darkened, somewhat paler at its margins; connexivum reddish with dark markings present on segments II–VI, narrow, complete, reaching external margin; on segments III–VI, approximately equivalent to somewhat less than a third and a fifth of the length of each segment at the inner and outer portions, respectively. Tarsi yellowish. Sternites generally black brownish with irregular pale transverse markings, ill-defined in shape, restricted or mostly present in the distal portion of the segment (sternites III and IV) or running along almost all of the median portion of the segment (sternites V–VII); dark coloration at distal halves of sternites II–VI reaches lateral margin of each segment, resulting in separate pale reddish marginal spots (Fig. 74).
STRUCTURE. Terminalia. Abdominal segment VIII similar to that of B. basalis. Male genitalia (Figs. 77–83) generally similar to those of B. basalis. Genital capsule: paramere (pa) apices far from each other in resting position; medial process of pygophore (mpp) visible in ventral view (Fig. 77). Dorsal phallotecal sclerite (dps) enlarged approximately at distal third, slightly sinuous in middle of anterior margin, laterally not sinuate, not folded at lateral margins (Figs. 82–83). Upper half of the median portion of endosomal struts (es) with a thin medial longitudinal linear cleft (lc) with almost straight edges (Fig. 83). After the endosoma quickly inflated spontaneously, basal portion of the external ventral layer (el) detached completely and its apical margin remained completely united to the apical portion of the endosoma (Fig. 80); the most reasonable explanation to this observed condition is that there was a ventral fold, but for some reason the external ventral layer was pulled, torn and detached from its base. Because of the existence of a fold, the apex of the endosoma was in continuity with the apical portion of the ventral layer (Fig. 80). Two endosoma processes: a basal large dense subtriangular process (stp); in the apex of the latter, the median process (mp) is attached by its midportion (Figs. 80–81). The median process (mp) is flat, finely striated, faintly sclerotized, somewhat more at the mid portion; shaped as a pair of arched portions (Fig. 81).
Type material examined. Brontostoma infensum Wygodzinsky, 1951: Male holotype: [handwritten:] Brontostoma / infensum / Wygod. / [printed:] Wygodzinsky det. / INST. MED. REG. // [a handwritten label glued on a larger card:] Sa Maria / Urundel Salta / XII-47 // [a red printed label glued on a larger card, last letters not readable by the hole and the glue on it:] HOLO …[probably… TIPO] (MACN). Male paratype: [handwritten:] Brontostoma / infensum / Wygodzinsky / [printed:] Wygodzinsky det. / INST. MED. REG. // [handwritten:] Urundel / Salta // [printed:] COLLECTIO / WYGODZINSKY // [handwritten red label:] PARATIPO (MNRJ).
Discussion. Brontostoma infensum was described based on four males from the same locality, Urundel, Salta, in Argentina (Wygodzinsky 1951). It was considered to be very similar to B. sanguinosum, from which it was supposed to be separated by the color differences stated in the aforementioned key. The total lengths of the type specimens were recorded as 28–29 mm (Wygodzinsky 1951). The specimens examined here, the holotype (Fig. 71) and a paratype (Figs. 73–75) are very similar to each other and agree well with the original description. Subsequently, the species was recorded from Brazil and Peru by Dougherty (1995).
Because the general coloration of Brontostoma infensum is similar to many specimens of B. basalis, and the latter species is highly variable in color, it is not possible to separate the two species by the color differences suggested by Wygodzinsky (1951). The examination of the type materials and several additional specimens in course of this work showed that only the following color differences are of diagnostic value: 1– the distal portion of the clavus and the adjacent area of corium are pale (yellowish) in B. basalis and dark in B. infensum; 2 – the membrane of the hemelytra is darker in B. infensum; and most importantly, 3– the shape of the pale transverse markings of sternites III–VII are irregular and ill-defined in shape in B. infensum (Fig. 74), but regularly bordered and symmetrical in B. basalis (e.g. Figs. 16, 21, 23, 25, 29, 31, 33). Yet, in B. infensum, these pale markings are mostly present in the distal portion of sternites III and IV or run along almost all median portion of sternites V–VII (Fig. 74) reaching the posterior margins of all these sternites, while in B. basalis, although variable in size, they do not reach the posterior margin of any segment, occupying approximately the basal portion of the sternites, as a pair of median pale markings in some segments (e.g. IV–VI; Figs. 21, 23) to almost all of them (III–VII; Fig. 25) or as transverse bands variably narrower at midportion (e.g. Fig. 29).
In the examined type specimens of B. infensum the distal antennal segments were missing, therefore it was not possible to ascertain the coloration of all antennal segments. Wygodzinsky (1951) recorded that only the fifth antennal segment (first distiflagellomere) was yellowish, with the remaining segments black (the first) to piceous. On the other hand, in B. basalis the coloration of antennal distiflagellomeres were recorded as varying from grayish to whitish, with the last segment commonly somewhat pale grayish, sometimes only at its apex. An evaluation of the diagnostic value of this color character could only be possible based on an examination of more specimens of B. infensum, which could reveal whether in the latter species the yellowish color is always restricted to the first distiflagellomere or also occurs in other distiflagellomeres as in B. basalis.
As a conclusion, B. infensum is recognized as a distinct species differentiated from B. basalis based on the following set of diagnostic characters of their male genitalia: 1 – paramere apices in resting position: very close or in contact (B. basalis) (Figs. 34, 38) or far from each other (B. infensum) (Figs. 77–78); 2 – medial process of pygophore in ventral view: not visible (B. basalis) (Figs. 34, 38) or visible between distant apices of parameres (B. infensum) (Figs. 77–78); 3 – Dorsal phallothecal plate: enlarged to the apex, deeply sinuous in center of anterior margin and more pronounced sinuate laterally to anterior margin and with lateral margins forming a ventral curved fold (vf), with an acute apex (vfa), projecting laterally (B. basalis) (Figs. 46, 49, 54, 56) or enlarged approximately at distal third, slightly sinuous in center of anterior margin, which laterally is not sinuate, and neither folded at lateral margins (B. infensum) (Fig. 82); 4 – Upper half of median portion of endosomal struts with conspicuous medial sinuous longitudinal borders in B. basalis (Fig. 56) or with a thin linear cleft whose edges are almost straight in B. infensum (Fig. 83).
The fully spontaneously inflated endosoma of B. infensum (Fig. 80) suggests that a ventral fold (evf) was present before the detachment of the external ventral layer (el). As a similar fold is present in B. basalis, it seems reasonable to suppose that these folds have no diagnostic value at species level in the taxa treated in this paper.
Dougherty (1995) recorded B. infensum from Argentina, Brazil and Peru. However, records from the latter two countries were based on non-type specimens identified based on their color and therefore they potentially represent misidentifications of B. basalis, and accordingly they are considered as in need of confirmation. It is noteworthy that B. basalis (including all its junior synonyms established here) has been recorded from several countries in South and even in Central America; B. infensum was recorded, aside from the doubtful records of Dougherty (1995), only from Argentina (Wygodzinsky 1951); the latter species is possibly restricted to the southern part of South America.
description: Published as part of Gil-Santana, Hélcio R., 2020, New synonymies among species of Brontostoma (Hemiptera: Heteroptera: Reduviidae), pp. 301-325 in Zootaxa 4869 (3) on pages 319-323, DOI: 10.11646/zootaxa.4869.3.1, http://zenodo.org/record/4418623