Belostoma inusitatum Stefanello & Rodrigues, 2021
|
publication ID |
https://doi.org/ 10.11646/zootaxa.5005.3.11 |
|
publication LSID |
lsid:zoobank.org:pub:AB3F6B90-F046-4694-A3B5-10BDAF609209 |
|
persistent identifier |
https://treatment.plazi.org/id/F50887BE-4D60-FFCC-FF64-FA2DFE17F8CC |
|
treatment provided by |
Plazi |
|
scientific name |
Belostoma inusitatum Stefanello & Rodrigues |
| status |
sp. nov. |
Belostoma inusitatum Stefanello & Rodrigues , new species
( Figs. 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 )
Description. Male, HOLOTYPE, total body length 26; maximum width 15.5. General shape pyriform ( Fig. 1A View FIGURE 1 ), widest at mid-length of hemelytra; overall dorsal coloration brown, with parts of pronotum, scutellum, and corium light-brown. Ventral surface brown.
Head. Eyes globose, small, lateral margin arched. Interocular space wide, 1.89× width of an eye ( Fig. 1B View FIGURE 1 ); anteoculus 1.73× interoculus, anteoculus 1.90, interoculus 1.10. Vertex without medial carina. Maxillary plate with upper and lower ends projected forward, covered with golden setae ( Fig. 1C View FIGURE 1 ). Lorogenal cleft without a conspicuous fovea. Antenna three-articulated, without lateral projections; article III longest, fusiform ( Fig. 1D View FIGURE 1 ). Labium fourarticulated; article II 0.79× length of III, II 1.50, III 1.90.
Thorax. Pronotum without medial carina; a pair of depressed rounded areas on disc at anterior half; transverse sulcus setting off band in posterior third; finely rugose, mainly on posterior third behind transverse sulcus; anterior margin concave medially; lateral margin straight; posterolateral corner right-angled; posterior margin straight, slightly angulated laterally; maximum width 2.4× length at midline, maximum width 9.10 (across posterolateral corners), length at midline 3.80 ( Fig. 1B View FIGURE 1 ). Prosternal keel projected forward, anterior margin excavated in lateral view ( Figs. 1E–F View FIGURE 1 ). Scutellum finely rugulose, mainly on posterior region; a pair of elevations near midline at anterior half; length at midline 5.10, maximum width 5.50. Hemelytra finely punctate throughout; embolar groove (=nodal suture) absent; membrane reduced, narrower than half maximum width of clavus ( Figs. 1A, G View FIGURE 1 ); hindwing with Mp and CuA veins merging in distal third; R+Ma gently curved posteriorly at the apex ( Fig. 1H View FIGURE 1 ); wing groove of mesoscutellum not widened, slightly convex. Mesepimeral projection extending posteriorly in dorsal view, almost reaching abdominal tergum II; wing knob rounded. Metanotum glabrous. Postalar metathoracic projection with lateral margin folded downward, gutter-shaped; length of postalar projection 0.82× length of mesepimeral projection. Metaxyphus swollen medially in anterior two-thirds, slightly depressed in posterior third, with distolateral margins converging at apex, forming an acuminate point.
Legs. Protibia at mid-length with lateral surface slightly narrower than mesal surface. Measurements as follows: foreleg, femur 6.30, tibia 3.80, tarsomeres 1–2 0.50, 0.50; middle leg, femur 7.35, tibia 5.55, tarsomeres 1–3 0.68, 1.10, 1.30; hind leg, femur 9.60, tibia 9.20, tarsomeres 1–3 0.73, 1.66, 1.77.
Abdomen. Pilosity covering less than half of connexivum, slightly constricted between intersegmental sutures; pilosity not developed on laterosternite VII and not covering sterna ( Fig. 1I View FIGURE 1 ). Air straps length 4.25, lanceolate, linear, only slightly constricted at mid-length, without dorsal sac. Male genitalia. Paramere elongate, narrowing towards apex, which is distinctly twisted up- and inward ( Figs. 2A–C View FIGURE 2 ). Dorsal arms of phallosoma slightly wider at base, exposing apical part of diverticulum in dorsal view; phallosoma weakly curved in lateral view, with slight dorsocaudal elevation and no ventroapical protuberance; diverticulum sharply incised at posterior margin ( Figs. 2D–G View FIGURE 2 ).
Female. Paratype (n=1), total body length 24; maximum width 13.5. Similar to male in general structure and coloration.
Diagnosis. The antenna three-articulated without lateral projections ( Fig. 1D View FIGURE 1 ), the prosternal keel projected forward with anterior margin excavated in lateral view ( Figs. 1E–F View FIGURE 1 ), and the diverticulum of the phallosoma sharply incised at the posterior margin ( Fig. 2D View FIGURE 2 ) are diagnostic for B. inusitatum n. sp.
Remarks. Despite the well-documented variation in body size and morphology of the male genitalia in species of Belostoma , B. inusitatum n. sp. represents a species that adds a previously undocumented and unexpected morphological variation. Formerly, all known species of Belostoma had been reported to exhibit four-articulated antennae with distinct lateral projections on antennomeres II and III; thus, the three-articulated antenna without lateral projections is recorded here for the first time in the genus. Although this species presents an unusual reduction in the number of antennal articles, the morphology of the male genitalia of B. inusitatum n. sp. agrees with that of congeners. The gonopore with no elevation above the dorsal arms of the phallosoma and the hooks of the parameres projecting medially perpendicular to the long axis of the parameres were determinant to describe the new species in Belostoma instead of Abedus . These two putative synapomorphies of Belostoma are here considered for the first time after the first author (FS) has examined a great number of specimens of different species from both genera. Some important features that led us to recognize that B. inusitatum n. sp. was a member of the triangulum species group were: small body size, broad body, small globose eyes, labial article II almost as long as III, reduction of the hemelytral membrane, and diverticulum of the phallosoma elliptical, slightly curved downward, and without ventroapical protuberance. Accordingly, the B. triangulum group is rearranged and now it comprises three species: B. bachmanni De Carlo, 1957 , B. inusitatum n. sp., and B. triangulum Lauck, 1964 .
Etymology. The specific epithet inusitatum (from Latin) means rare, unusual, and refers to the set of atypical features of this species, including the reduction in the number of the antennal articles and hemelytral membrane, and the diverticulum of the phallosoma sharply incised at the posterior margin.
Distribution. This species is known only from two localities on the west side of the Araguaia-Tocantins basin, in Mato Grosso state in central-western Brazil ( Fig. 3 View FIGURE 3 ).
Type material. HOLOTYPE, ♂: BRAZIL, Mato Grosso, Barra do Garças, Córrego Papagaio , 1908, 3rd or- der, seg. 20, 15°28’11”S, 52°24’32”W, 19.xi.2005, H. Cabette et al. col. ( CEIOC) GoogleMaps . PARATYPE: BRAZIL, Mato Grosso, Barra do Garças, Córrego Caveira , 3829, 3r order, seg. 8, 14°57’28”S, 52°13’43”W, 03.xi.2007, H. Cabette et al. col. (1♀ CEIOC) GoogleMaps .
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
|
Kingdom |
|
|
Phylum |
|
|
Class |
|
|
Order |
|
|
Family |
|
|
Genus |