Macropygium Spinola 1837
Creators: name: Silva, Layse Mitsue Harada Da
name: Campos, Luiz Alexandre
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hemiptera
Pentatomidae
Macropygium

description: Macropygium Spinola, 1837
Macropygium Spinola, 1837: 287; Herrich-Schäffer, 1844: 48; Stål, 1867: 523; Stål, 1872: 4. P. 12; Distant, 1880: 49; Berg, 1884: 181; Dallas, 1851: 150–159; Kirkaldy, 1909: 184; Rolston, 1992: 5, 24–25; Campos & Grazia, 2006: 147, 151, 160, 162; Garbelotto et al., 2013: 454; Roell & Campos, 2018: 1139.
Oxyrhinus Amyot & Serville, 1843 (synonymized by Dallas 1851).
Type species: Cimex reticularis Fabricius, 1803 (senior synonym of Macropygium atrum Spinola, 1837).
Diagnosis. Medium size (10.0– 13.9mm); oval body, brown or dark brown with black irregular spots, anterolateral margins of pronotum yellowish in some specimens (Figs 1, 2); head triangular; mandibular plates surpassing apex of clypeus, touching each other in some specimens; four or five antennomeres, antepenultimate antennomere wider in males than females. Pronotum slightly sloping anterior to the humeri; scutellum shorter than coria; apex of rostrum surpassing urosternite III. Male urosternite VII, in the middle line, as long as or longer than all remainder abdominal segments taken together. Pygophore large, occupying more than a third of the abdominal cavity.
Description. Head triangular; mandibular plates surpassing the apex of clypeus, converging each other, or only touching each other in some specimens; anteocular processes spinose. Eyes pedunculated; ocelli posterior to a line connecting the hind margins of eyes; small punctures forming wrinkles over mandibular plates; antennae with four or five antennomeres; insertion of the labium posterior to an imaginary line tangent to the anterior margin of the eyes; apex of rostrum surpassing urosternite III.
Pronotum wider than long; dorsal surface of anterolateral margins flattened;anterior margin sinuous; anterolateral angles with a small triangular projection; cicatrices weakly tumid, smooth or with rare, inconspicuous punctures. Scutellum triangular, longer than wide, shorter than coria; completely brown or with small yellow spots: 1+1 near the foveae, one median at anterior margin, and one apical. Frenal lobe twice as long the postfrenal lobe. Coria covered by fine and sparse punctures; apical angle surpassing connexivum V; hemelytral membrane may extend beyond the abdominal apex. Meso- and metasternum smooth, bearing flat median carina; pleura rugose, uniformly dark brown or with irregular yellowish spots; evaporatorium smooth, velvety, covering one-third of the metapleura; peritreme short, spout; legs yellowish with brown rounded spots on femora and tibiae. Abdominal sternites with dark spots.
Male: antepenultimate antennomere wider than each the two last; large trapezoidal pygophore, occupying about 1/3 of the abdominal cavity; ventral rim with a medial conical projection (Fig. 4A; cp); dorsal rim bearing 1+1 lateral projections directed dorsoposteriorly (Fig. 4B–D, O; lp); posterolateral angles acute, directed dorsoposteriorly (Fig. 4B–D; pl), with a broad medial projection (Fig. 4B–D; ppla), this rounded at apex and directed dorsally. Apex of parameres visible posteriorly and ventrally between the posterolateral angles, ventral to segment X (Fig. 4D; par). Segment X broad, ogival, surpassing posteriorly both the ventral rim and the posterolateral angles (Fig. 4B, C; X). Anal opening subapical, dorsal to the posteriorly projected portion of segment X, this slit opened ventrally to give way to the phallus. Phallus highly sclerotized; phallotheca piriform, narrowed apically; vesica twisted and accompanying the ductus seminis distalis; conjunctiva reduced, surrounding vesica (Fig. 5M–Y).
Female: antepenultimate antennomere the same width as the two last; posterior margin of valvifers VIII projecting over the base of laterotergites IX; sutural margins juxtaposed; disc evenly convex. Laterotergites VIII triangular, spiracles visible at basal angle lateral to valvifers VIII. Valvifers IX exposed, posterior margin biconcave; laterotergites IX trapezoid, touching each other in the medial angle; medial margins divergent; apex rounded. Segment X partially exposed between the laterotergites IX (Fig. 6). Valvulae IX weakly sclerotized near the ring sclerites; infoldings of valvulae IX extending from valvifers IX almost to the ring sclerites; vaginal intima barely thickened, almost indistinguishable; proximal portion of ductus receptaculi large, wider than median duct of vesicular area, this globose at base; inner duct of vesicular area narrowing from the proximal aperture to the apical limit of the vesicular area; capsula seminalis globose with thin processes as long as the pars intermedialis, the latter twice longer than capsula seminalis (Fig. 7).
Comments. The species of Macropygium show a cryptic body morphology, and species recognition is only possible assessing the genital morphology. The only exception is the new species, Macropygium graziae sp. nov., whose antennae are four-segmented, while five-segmented in all the other species. Phylogenetic hypotheses (Campos & Grazia 2006; Garbelotto et al. 2013; Roell & Campos 2019) recovered Macropygium in the same clade with Uvaldus and Clypona. Macropygium can be easily distinguished from Uvaldus (Fig. 3A) by the larger size, darker color, and longer mandibular plates; and differs from the monotypic Clypona (Fig. 3B, C) by two subtle characteristics, the second rostral segment slightly longer than the first segment, and the base of clypeus triangular in ventral view (Rolston 1992). There is no clear difference in the genital plates between Clypona aerata Rolston, 1992 (Fig. 3C) and Macropygium spp. (Fig. 6). Because the male of C. aerata is unknown, the validity of Clypona as a separate genus and its relationship with the species of Macropygium are still to be investigated.
Key to the species of Macropygium
Because the species of Macropygium show a cryptic body morphology, the present identification key is based mostly in characteristics of genital morphology.
1 Antennae with five segments (Figs 1A–D, 2A, B); male with lateral projections of dorsal rim of pygophore slim, placed near the posterolateral angles (Fig. 4C, G, K); female with lateral portion of posterior margin of valvifers VIII projected over laterotergites IX (Fig. 6A–C, E)......................................................................... 2
- Antennae with four segments (Fig. 2C); male with lateral projections of dorsal rim of pygophore wide, placed away from the posterolateral angles (Fig. 4O); female with middle portion of posterior margin of valvifers VIII projected over laterotergites IX (Fig. 6D)................................................................. Macropygium graziae sp. nov.
2 Male segment X subquadrangular in posterior view (Fig. 4H); lateral portion of the posterior margin of female valvifers VIII projected over laterotergites IX well beyond the spiracles of laterotergites VIII, attaining or surpassing an imaginary line connecting the medial thrichobothria of urosternite VII (Fig. 6B)..................... Macropygium spinolae Stål, 1860
- Male segment X subrectangular in posterior view (Fig. 4D, L); lateral portion of the posterior margin of female valvifers VIII not exceeding the imaginary line of thrichobothria and the third part of valvifers VIII (Fig. 6A, C, E).................. 3
3 Male conical projection of ventral rim of pygophore bifurcate at apex (Fig. 4I); lateral portion of the female laterotergites VIII slightly deflected, and posterior angle oval (Fig. 6C)......................... Macropygium bifidum (Westwood, 1837)
- Male conical projection of ventral rim single at apex (Fig. 4A, cp); lateral portion of the female valvifers VIII not deflected, and posterior angle rounded (Fig. 6A, E)...................................................................... 4
4 Posterior angle of valvifers VIII not reaching the lateral margin of laterotergites IX; maximum width of valvifer VIII about 0.7 times the length at the sutural margin (Fig. 6A)............................ Macropygium reticulare (Fabricius, 1803)
- Posterior angle of valvifers VIII not covering the lateral margin of laterotergites IX; valvifer VIII rounded, maximum width of valvifer VIII about 0.9 times the length at the sutural margin (Fig. 6E)..................................................................................................... Macropygium subsulcatum (Amyot & Serville, 1843)
description: Published as part of Silva, Layse Mitsue Harada Da & Campos, Luiz Alexandre, 2021, Revision of Macropygium Spinola, 1837 (Hemiptera: Pentatomidae: Ochlerini) with the revalidation of three species and the description of one new species, pp. 605-627 in Zootaxa 4958 (1) on pages 606-612, DOI: 10.11646/zootaxa.4958.1.36, http://zenodo.org/record/4692609