Sclerocoelus limbus, Kuwahara & Marshall & Paiero, 2025

Kuwahara, Gregory K., Marshall, Stephen A. & Paiero, Steven M., 2025, A revision of the genus Sclerocoelus Marshall (Diptera: Sphaeroceridae), European Journal of Taxonomy 979, pp. 1-277 : 71-72

Sclerocoelus limbus sp. nov.

urn:lsid:zoobank.org:act:6921C506-F8A6-421E-88D3-0ABD4191CE97

Figs 7E , 75–77

Etymology

This name refers to the long fringe of thickened setae along the posterior margin of the male S5 (from the Latin ‘ limbus ’, meaning ‘border, edge, fringe, hem’).

Material examined

Holotype

BOLIVIA • ♂; Cochabamba, 72 km E of Cochabamba; 2850 m a.s.l.; 3 Feb. 1999; R. Anderson leg.; Yungas, wet litter; CBFC debu00127173.

Paratypes

BOLIVIA – Santa Cruz • 1 ♀; Kara Huasi, Yungas de la Siberia , 26.4 km NW of Comarapa; 2600 m a.s.l.; 27 Jan. 1999; R. Anderson leg.; mixed yungas/bamboo litter; CBFC • 1 ♂; same data as for preceding; debu00111049/ MYCRO901-21 sequenced for CO1-5’; DEBU .

PERU – Cusco • ♂; Wayqecha Biological Station , ~ 9 km NE of Challabamba; 13°11′18″ S, 71°35′06″ W; 3100 m a.s.l.; 7–8 Dec. 2011; S.A. Marshall leg.; MUSM .

Description

BODY ( Fig. 75A ). Length 3.0– 3.4 mm. Head dark brown, margin of frons, center of face, and antenna orange. Frontal width 2.2–2.3× frontal height. Two pairs of large interfrontal bristles surmounting a fine third; anterior orbital 0.5–0.6× length of posterior. Palpus pale brown. Eye large, greatest height about 3.0× shortest genal height. Thorax dark brown, scutum shiny with slightly paler lateral edges. Two pairs of dorsocentral bristles (anterior pair distinct, 0.4× length of posterior pair) separated by 6–7 rows of acrostichal setulae. Membrane around prosternum bare. Legs brown, femora apically yellow. Fore femur with four large ventral preapical setae. Ventral surface of male mid tibia with two rows of stout setae along apical third. Wing ( Fig. 7E ) short, extending only to T3 or T4; infuscate. All veins distinguishable. CS2 0.6–0.7 × CS3. Halter significantly reduced, stem short and white, knob ~3.0 × size of ocellus and brown.

MALE ABDOMEN ( Figs75B–C , 76 ).Dark brown, posterior edges of tergites sometimes slightly desclerotized. T2–5 and S2–4 uniformly long-setose with large posterolateral setae. S5 broad, rectangular, 0.8× length of S4, setae almost entirely restricted to posterior margin, medially pale with a dark, anteriorly Y-shaped, posteriorly triangular, posteromedial patch surrounded by 2 dark, rhombic sclerotized patches bearing thickened posterior setae. Anterior flange of S6+7 not developed. Sclerite A a small lobe not distinctly differentiated from S6+7; sclerite B long, dark, arched; sclerites C and D apparently absent; sclerite E small, dark, flattened ventrally, broadened dorsally and fused to sclerite F; sclerites F and G fused, large, flat, and weakly sclerotized; ring sclerite indistinct. Epandrium small, 0.7× length of S8, height 1.9× maximum length and 0.7× maximum width, uniformly setose; perianal pads weakly developed. Pseudocercus absent; halves of subepandrial sclerite relatively straight, medially fused. Cercus large, almost parallel-sided in posterior view, with a posterior bulge about midlength, basal half with 3 posterior setae and dense setulae. Hypandrium with long, thin anteromedial apodeme. Surstylus broadly rounded, bulging, laterally and ventrally densely setose with a bare, flattened, anterior lobe. Postgonite short, basal two-thirds relatively parallel-sided, apical third tapered, curved with dense setulae along inner surface, apex emarginate. Phallapodeme long, slightly sinuate; basiphallus round basally with a narrowed, neck-like extension to base of distiphallus; distiphallus large, largely membranous with a very broad, scoop-like ventral membrane and a curled, sinuate, dorsally setulose dorsomedial sclerite.

FEMALE ABDOMEN ( Fig. 77 ). T7 broad, simple; T8 desclerotized dorsomedially, leaving two large, dark, lateral sclerites, posterolateral corners greatly expanded and rounded. Epiproct large, subrectangular, medially split, and sparsely setulose around setae. Cercus elongate, apically pointed with long, curved apical and dorsal setae. S7 broad, broadly desclerotized posteriorly with 4–6 large posterior setae; S8 reduced to a very small, setulose, medial sclerite. Hypoproct broad, densely setulose in apical third. Three spermathecae, bulb stout, spherical, finely striate with a deep basal and a shallow apical invagination, invaginations almost touching.

Distribution

Neotropical: Bolivia, Peru.

Remarks

Sclerocoelus limbus sp. nov. is easily recognized by the strongly shortened wings, strong posterior setae on the male S5, and almost semicircular lateral sclerites of the female T8. Sclerocoelus limbus has distinct cerci fused basally into a subanal plate, and it lacks separate pseudocerci or subcerci. These characters suggest that S. limbus and the similarly brachypterous species S. aduncus sp. nov., S. flavus sp. nov., and S. meridensis sp. nov. are among the few species in the genus basal to the large, derived groups characterized by separate subcerci and pseudocerci. All four species are associated with wet, green plant material in high elevation cloud forests or elfin forests in the Andes.

Figures

Fig. 7. Sclerocoelus Marshall, 1995, left wings, ventral view. A. Sclerocoelus inornatus sp. nov. B. Sclerocoelus irregularis sp. nov. C. Sclerocoelus latibarbus sp. nov. D. Sclerocoelus lazulita sp. nov. E. Sclerocoelus limbus sp. nov. F. Sclerocoelus longibarbus sp. nov. G. Sclerocoelus lutosus sp. nov. H. Sclerocoelus mandibulum sp. nov. I. Sclerocoelus masneri sp. nov. J. Sclerocoelus meridensis sp. nov. Scale bars: A–J =0.5 mm.

Fig. 75. Sclerocoelus limbus sp. nov. A. Male paratype habitus, lateral view (debu00111049). B. Male holotype terminalia, posterior view (debu00127173). C. Male holotype terminalia, lateral view (debu00127173). Abbreviations: cer =cercus; epa =epandrium; se =subepandrial sclerite; ss= surstylus. Scale bars: A= 1.0 mm; B–C =0.25 mm.

Fig. 76. Sclerocoelus limbus sp. nov., male holotype (debu00127173). A. Aedeagus and associated structures, lateral view. B. Male S5 and genital pouch, ventral view. Abbreviations: bp =basiphallus; dp =distiphallus; pg =postgonite; ph =phallapodeme. Scale bars: A=0.13 mm; B=0.25 mm.

Fig. 77. Sclerocoelus limbus sp. nov., paratype (debu00111051). A. Female terminalia, dorsal view. B. Female terminalia, ventral view. C. Female terminalia, lateral view. D. Spermatheca. Scale bars: A–C =0.25 mm; D =0.03 mm.