Mecomera chacoensis (Borelli, 1912)

Heleodoro, Raphael Aquino, Alves-Oliveira, João Rafael & Rafael, José Albertino, 2019, Mecomera Audinet-Serville, 1839 (Dermaptera: Spongiphoridae): proposal of new diagnosis, descriptions and illustrations of all three-known species, Zootaxa 4577 (1), pp. 117-130 : 124-126

Mecomera chacoensis (Borelli, 1912)

Figs. 6 A–E.

Metasparatta chacoensis Borelli, 1912: 2 ; Brindle, 1968: 289 (short description and illustrations after Borelli).

Mecomera chacoensis ; Steinman 1990: 171 (new combination).

Examined material. Chaco de Santiago Del Estero [ Argentina], Bords do Rio Salado Env. Dicaño , E. R. Wagner, 1904 (Holotype ♂ MNHN); Venezuela , Yaracuy, Yumare , 1–5.vi.1970 [new record] .

Diagnosis. Eye diameter about 0.8 times length of post-ocular area ( Fig. 6A ). Antenna uniformly light brown ( Fig. 6A ). Tegmina light yellow, translucid ( Fig. 6A ). Cercus with four to six acute projections, pointing to venter ( Fig. 6A ). Pygidium dorsally descending from base towards apex; apical margin with four rounded elongated projections, each pointing latero-posteriorly; ventrally flattened ( Figs. 6 B–C). Basal vesicle of the male genitalia resembling an elongated crab claw, sinuous, bifurcated at apex, forming concavity; connected to a “C” shaped sclerite, strongly sclerotized ( Figs. 6 D–E). Paramere partially sclerotized, with small membranous area at apex; exterior margin gradually curving, concave; internal margin conspicuously curving, concave; apex straight, thin ( Figs. 6 D–E).

Description of male. Body light brown to light yellow ( Fig. 6A ).

Head cordiform, smooth ( Fig. 6A ). Frons and vertex with inconspicuous postfrontal and coronal sutures. Frons with basal margin inconspicuously sinuous. Post-ocular area with postero-lateral margin rounded; vertex conspicuously concave. Eyes light brown (in dead specimen), diameter about 0.8 times length of post-ocular area ( Fig. 6A ). Antenna setose from base to apex, light brown ( Fig. 6A ); scapus 3.4 times longer than pedicel and 1.1 times longer than flagellomere 1. Maxillary and labial palps setose.

Pronotum hexagonal, 1.6 times longer than wide when measured at widest point; broadening from base to apex, wider at middle, roughed surface, apical, basal and lateral margins convex; mid-longitudinal sulcus inconspicuous and shallow; metazone length 11 times that of prozone ( Fig. 6A ). Meso- and metanotum covered by tegmina and posterior wings, respectively. Sternum light yellow. Prosternum with sternal plate cylindrical, with all margins conspicuously curved. Mesosternum with conspicuous sternal plate, with truncated basal and apical margin, broadening towards sinuous lateral margin. Metasternum with inconspicuous sternal plate.

Tegmina light yellow, translucid, elongated, 2.2 times longer than wide, broadening towards apex; surface roughened, postero-laterally emarginated ( Fig. 6A ).

All legs shiny, light yellow ( Fig. 6A ). Posterior legs with conspicuous brown spot dorsally. All femora lacking setae; tibiae and tarsi with setae ventrally.

Abdomen with lateral margins parallel-sided, dorsally and ventrally covered with small, scattered, smooth setae; all segments apically striated dorsally and ventrally. Tergites 1–3 not narrowed. Tergites 3–4 dark brown, with inconspicuous glandular folds. Tergites 3–9 rectangular; tergites 3–7 approximately three times wider than long, with apical margin concave. Tergite 8 approximately 2.5 times wider than long, with apical margin concave ( Fig. 6A ). Tergite 9 approximately 7.6 times wider than long, with apical margin concave ( Fig. 6A ). Tergite10 (ultimate) with lateral margins convex, apical margin slightly emarginated with postero-lateral margin projected ( Fig. 6A ). Pygidium dorsally descending from base towards apex; basal margin straight, lateral margin sinuous, apical margin with four rounded, elongated projections, each pointing latero-posteriorly; the concavity between projections wide, deep; ventrally flattened ( Figs. 6 B–C). Cercus robust, light brown, gradually curving at apical margin, with four to six acute projections, pointing to venter. Sternites 2–7 rectangular, with lateral margin somewhat straight, apical margin emarginated, slightly concave. Sternite 8 the same, but apical margin straight ( Fig. 6C ). Sternite 9 (penultimate) “D”-shaped, with lateral margin convex, apical margin inconspicuously emarginated ( Fig. 6C ).

Male genitalia ( Fig. 6 D–E) with functional ejaculatory duct right-sided, approximately 5.5 times longer than virga; well sclerotized, elongated dark brown sclerite accompanying the ejaculatory duct longitudinally. Basal vesicle resembling an elongated crab claw, sinuous, bifurcated at apex, forming concavity, connected to a “C”- shaped sclerite, strongly sclerotized. Virga elongated, reaching base of paramere. Penis lobe broad, convex, symmetrical, smooth. Paramere partially sclerotized, with small membranous area at apex; exterior margin gradually curving, concave; internal margin conspicuously curving, concave; apex straight, thin.

Remarks. The “C” shaped sclerite connected to the basal vesicle may be an independent sclerite, despite the two of them being connected. Furthermore, it appears the “C”-shaped sclerite is also connected to the ejaculatory duct.

Mecomera chacoensis differs from M. reichardti by the pygidium with four elongated rounded projections ( M. reichardti with two bifurcated oblong projections). Furthermore, M. chacoensis has the basal vesicle resembling a crab claw, slender and sinuous at basal half, bifurcated at apical half ( M. reichardti has the basal vesicle conspicuously slender at proximal half, rounded at distal half, resembling a comma).

Figures

FIGURE 6. Mecomera chacoensis ♂. A) Habitus, dorsal view; B) Pygidium and cercus base, dorsal view; C) Pygidium and subgenital plate, ventral view; D) Genitalia, dorsal view; E) Genitalia, ventral view.