Sphaeridops pallescens (Walker, 1873)

Gil-Santana, Hélcio R., 2021, A revision of Sphaeridops (Hemiptera: Heteroptera: Reduviidae), Zootaxa 5020 (3), pp. 521-549 : 541-547

Sphaeridops pallescens (Walker, 1873)

( Figs. 73–91 )

Reduvius pallescens Walker, 1873a: 183 . Holotype: ♂, Amazon Region; BMNH. Erroneously synonymized with Sphaeridops amoenus ( Lepeletier & Serville, 1825) [misspelled as S. amaenus ] by Costa Lima (1940: 207). Reinstated species.

Reduvius pallescens: Lethierry & Severin, (1896: 119) (catalog, as of doubtful generic placement within subfamily Acanthaspidae ).

Distribution. Brazil.

Diagnosis. Sphaeridops pallescens can be separated from its two congeners by its pale, whitish, yellowish or orange general coloration; the body is reddish to pale reddish or orange reddish in S. amoenus , while the blackish markings are generally smaller in number and extension in S. pallescens . While the general coloration of S. pallescens and S. aurantius is similar, the following differences allow their separation: lateral markings of hind lobe of pronotum rounded and smaller ( S. pallescens ) ( Figs. 73 , 76, 78 ) or elongated and larger ( S. aurantius ); membrane of hemelytra with veins as pale as the surrounding membrane and a median rounded faint dark spot on approximately midportion of distal fourth ( S. pallescens ) ( Figs. 73 , 76, 78 ) or with some veins or portions of them variably darkened to blackish ( S. aurantius ); connexivum with distal blackish markings on segments II–VI ( S. pallescens ) ( Figs. 73 , 76, 78 ) or completely pale, without dark markings ( S. aurantius ). Sphaeridops pallescens can readily be separated from the other two congeners by its male genitalia, particularly, the slightly enlarged basal portion of medial process of pygophore (mpp) ( Figs. 82–83 ) and the enlarged basal plate bridge (bpb) which has a prolongation on its upper portion ( Fig. 84 ). The basal processes (bp) of endosoma are somewhat broader than to those of S. aurantius , but in the latter species almost all the margins are remarkably undulated, while in S. pallescens , only the basal margins are undulated ( Fig. 89 ); the basal processes (bp) of both species differ in relation to S. amoenus , in which they are enlarged and with margins faintly or not undulated. Pair of groupings of sclerotized longitudinal linear shallow ridges of the subbasal processes (sbp) slightly divergent towards their apices in S. pallescens ( Fig. 90 ), slightly curved at distal half in S. amoenus and subparallel in S. aurantius ; the ridges more numerous at approximately the distal third in the latter species, and at approximately the distal two-thirds in the other species.

Redescription (based on the holotype and a single non-type male). Male. Body length (larger values represent holotype): 16.8–19.5 mm; maximum width of abdomen: 6.5–7.8 mm. Coloration and variability ( Figs. 73–74 , 76–79 ): Body pale orange, yellowish to whitish with blackish markings or portions. Scape blackish; in the nontype pedicel dark, becoming paler towards apex, flagellomeres yellowish pale with scattered small dark spots; legs generally dark brownish to blackish; fore coxae with a pale portion in its inner surface in the holotype and mostly pale in the non-type; tibial pads pale; second tarsomere paler basally, more extensively in fore legs. Connexivum with distal blackish markings on segments II–VI ( Figs. 73 , 76, 78 ). Head. Ocellar tubercle darkened around ocelli in the non-type; second visible labial segment variably darkened, brownish. Thorax. Fore lobe with a pair of small dark spots below point of union between anterior collar and anterolateral angles in the holotype ( Fig. 73 ); a longitudinal median dark stripe runs from transverse furrow to approximately somewhat more than proximal two-thirds of hind lobe; this stripe is wider basally, narrowing towards the apex in the holotype ( Fig. 73 ) and narrower, with an almost uniform width, in the non-type ( Figs. 76, 78 ); on hind lobe a pair of small blackish lateral rounded markings ( Figs. 73 , 76, 78 ). Lateral margins of scutellum dark ( Figs. 73 , 76, 78 ). Pleurae with dark markings, forming two separated spots on propleura, larger in the holotype, and stripes on upper portion of meso and metapleura. Mesosternum largely dark at lateral portion ( Figs. 74 , 77, 79 ); metasternum darkened on lateral margin, just above hind coxae. Hemelytra ( Figs. 73 , 76, 78 ) with subrounded, suboval or subtriangular dark markings on: basal portion of inner cell of membrane; a portion of corium above but somewhat far from basal portion of outer cell of membrane; inside basal portion of latter, and apex of corium; dark marking inside basal portion of outer cell of membrane smaller and fainter in the holotype. Additionally, membrane of hemelytra with a small dark spot at extreme base of lateral vein of outer cell and a larger, fainter rounded spot at approximately midportion of its distal fourth ( Figs. 73 , 76, 78 ).

Abdomen. Sternites III–VI with midlateral basal subrounded, dark spots, approximately of same size ( Figs. 74 , 77, 79 ); sternite VII with pair of short, narrow, submedian basal dark stripes, slightly narrower and further from each other in holotype ( Figs. 74 , 77, 79 ); laterally, approximately between level of midlateral basal spots and margins of connexivum, at a submedian distal position, on sternites III–VII, smaller (holotype) or larger (non-type specimen) subrounded dark spots ( Figs. 74 , 77, 79 ). Exposed portion of pygophore without markings (holotype) or somewhat darkened at median portion (non-type specimen) ( Figs. 74 , 77 ). Vestiture: setosity of body generally shorter and less developed; long setae on dorsal portion of cylindrical prolongation of prosternum moderately numerous. Structure. Pronotum: median sulcus shallow, running from transverse sulcus and reaching approximately proximal portion of the distal third; ridges at its margins slightly or not elevated. Hind lobe: wrinkles of integument not pronounced; lateroposterior margins curved, midposterior margin less and more curved in the holotype and in the non-type, respectively ( Figs. 73 , 76, 78 ). Process of scutellum elongated, obliquely elevated in the holotype ( Figs. 73 , 76, 78 ). Median keel extending on sternites II–VI, more pronounced on segments III–VI, absent on distal portion of latter, well developed in the holotype and shallower in the non-type ( Figs. 74 , 77, 79 ). Apex of hemelytra not reaching apex of the abdomen, distant of it by a variable distance ( Figs. 73 , 76 ). Male terminalia. Abdominal segment VIII: median portion of anterior margin of ventral face deeply curved; posteroventral margin straight ( Fig. 80 ). Male genitalia ( Figs. 80–91 ): Pygophore: parameres not visible or only with their posterior margins barely visible in ventral view ( Figs. 80–81 ); on ventral face of pygophore a basal median depression and lateroposterior portions (lpp) slightly elevated and elongated ( Figs. 80–81 ); distal portion of pygophore somewhat large, forming a horizontal extension of pygophore wall. Medial process of pygophore (mpp) only visible in dorsal and lateral views of pygophore, situated at some distance from posterior margin; in anterior view, slightly enlarged and subtriangular in shape at basal and apical portions, respectively ( Figs. 82–83 ). Phallus ( Figs. 84–88 ): basal plate bridge (bpb) enlarged, with a prolongation on upper portion and bent ventrally ( Fig. 84 ); each membranous lobe on endosoma (mle) rounded to suboval ( Figs. 84–85 ). Processes of endosoma ( Figs. 87, 89–91 ): basal processes (bp) ( Figs. 87, 89 ) with only their basal margins undulated; pair of groupings of sclerotized longitudinal linear shallow ridges of subbasal processes (sbp) slightly diverging towards their apices; numerous ridges at approximately distal two thirds ( Fig. 90 ).

Type material examined. Holotype: ♂, [printed labels:] 9. REDUVIUS PALLESCENS . // [rounded label with green circle:] Type // [rounded label with red circle:] Holo- / type // QR code / NHMUK 013585370 // BMNH (E) / #651124 // ♂ // [handwritten rounded label:] Braz [opposite side of same label]: 62 / 57: ( BMNH).

Additional specimen examined. BRAZIL: Rondônia, Porto Velho, Bairro Novo, Condomínio Lírio Torre 33, 08º48’58.83”S 63º48’31.95”W, inside a wardrobe in a residential apartment, 23.i.2019, Genimar Rebouças Julião leg., 1 male ( MNRJ) .

Comments. Reduvius pallescens was described based on a male (the holotype) from the “Amazon Region” ( Walker 1873a) ( Figs. 73–75 ), without any additional information. One of the original labels of the holotype reads “Braz” on one side ( Fig. 75 ), which quite evidently stands for Brazil, consequently the individual was very likely collected in the Brazilian Amazon , similarly to the recently collected non-type male examined ( Figs. 76–79 ) .

The species was synonymized with S. amoenus [misspelled as S. amaenus ] by Costa Lima (1940: 207), and all subsequent authors listed it accordingly ( Wygodzinsky 1949, Maldonado 1990).

The non-type male examined was preserved in alcohol 70º since its capture, for about two years. In course of the present study it was removed from the preservative and dried. Some of its dorsal and ventral photographs provided here were taken just after its removal from preservative ( Figs. 76–77 ), others after complete drying ( Figs. 78–79 ), in an attempt to record possible changes of the color or tone during drying. The most remarkable change, however, was the spontaneous deformation of the abdomen, including shrinkage both in its length and width after the individual was completely dried ( Figs. 78–79 ). While the first photographs show the true shape and dimensions of the abdomen ( Figs. 76–77 ), those of the dried specimen show some details of the coloration more clearly ( Figs. 78–79 ).

The antennal segments of all examined specimens of S. amoenus and S. aurantius (when present) were dark to blackish, while in the available non-type of S. pallescens the pedicel was paler in the apical portion, and the flagellomeres were yellowish pale with scattered small dark spots ( Figs. 76–79 ). However, the original description ( Walker 1873a) stated that the antennae were black. The antennae of the holotype, except of the left scape, are unfortunately lacking ( Figs. 73–74 ). The original description further recorded about the antennae: “first joint very short; second twice as long as the first; third more than thrice as long as the second” ( Walker 1873a). This does not match with the relative lengths of the segments of any species of Sphaeridops , including the non-type specimen of S. pallescens examined here, because in all known species of this genus, the second segment (pedicel) is always much more than twice longer than any other antennal segment, while the third is always much shorter than the second. This controversy suggests that the original description is badly inaccurate in respect of the antenna (probably both of its color and relative lengths of the segments) and it should be omitted. An examination of additional specimens would be necessary do decide whether the coloration of the pedicel and flagellomeres seen in the examined non-type specimen is diagnostic for S. pallescens (in contrast with the other species which bear uniform dark antennae), or subject of individual variability, or perhaps a result of the long storage of the specimen in a liquid medium.

It is noteworthy that although Walker (1873a) recorded the general coloration of R. pallescens as testaceous, the holotype is rather pale yellowish to pale orange ( Figs. 73–74 ). As the color of the holotype is very similar to that of the recently collected non-type ( Figs. 76–79 ), the conflict between the original description and the holotype is probably due to the inaccuracy of the description rather than a potential subsequent fading of the specimen over the past one and half century. The specific epithet, pallescens (= faint, faded) is also in accordance with the actual coloration of the holotype and not the color mentioned in the original description. The synonymy of S. pallescens and S. amoenus , proposed by Costa Lima (1940), may have been at least partly motivated by the color of the species of the species erroneously stated as testaceous in the original description, which would indeed be similar to the condition found in S. amoenus .

Based on its color, S. pallescens is much more similar to S. aurantius than to S. amoenus . Nevertheless, S. pallescens can be promptly separated from S. aurantius by various color features detailed in the diagnoses of both species above and the key below. Male genitalia of S. pallescens , particularly the characters listed in the diagnosis above, are prone to separate this species from the two known congeners. Therefore, S. pallescens is hereby removed from the junior synonymy of S. amoenus proposed by Costa Lima (1940) and it is reinstated as a valid species.

Figures

FIGURES 73–75. Reduvius pallescens Walker, 1873, male holotype. 73, dorsal view, scale bar 5.0 mm, 74, ventral view, 75, labels.

FIGURES 76–79. Sphaeridops pallescens (Walker, 1873), sp. reinst., male from Rondônia, Brazil, scale bars 5.0 mm. 76–77, specimen before drying; 78–79, specimen already dried; 76, 78, dorsal view, 77, 79, ventral view.

FIGURES 80–85. Sphaeridops pallescens (Walker, 1873), sp. reinst., male. 80–82, scale bars 1.0 mm; 80–81, ventral view, 80, abdominal segment VIII and pygophore, 81, pygophore, schematic outline; 82, pygophore, dorsal view, setae omitted; 83–85, scale bars 0.5 mm; 83, posterior margin of pygophore and medial process of pygophore, schematic outline, anterior view; 84–85, phallus, 84, dorsal view, 85, lateral view, ap, apical processes of endosoma, bpa, basal plate arm, bpb, basal plate bridge, br, transverse bridge, gr, grooves, lpds, lateral portion of dorsal phallothecal sclerite, lpp, lateral posterior elevated portions of pygophore, mle, membranous lobe on endosoma, mpp, medial process of pygophore, pa, paramere, pct, proctiger, pd, pedicel, st, struts.

FIGURES 86–91. Sphaeridops pallescens (Walker, 1873), sp. reinst., male genitalia. 86–87, phallus, scale bars 0.5 mm; 86, ventral view, 87, ventrosuperior view; 88–91, dorsal view; 88–89, scale bars 0.1 mm; 88, apical portion of pedicel and struts; 89–91, processes of endosoma, 89, basal processes, arrows point to undulating basal margins, 90–91, scale bars 0.2 mm, 90 subbasal processes, arrow points to the apical portion of a grouping of sclerotized linear shallow ridges, 91, subapical and apical processes, ap, apical process of endosoma, bp, basal process of endosoma, lpds, lateral portion of dorsal phallothecal sclerite, pd, pedicel, sp, subapical process of endosoma, st, struts.