Sclerocoelus dominicensis, 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 : 50-51

Sclerocoelus dominicensis sp. nov.

urn:lsid:zoobank.org:act:E1B2E330-F92F-4B17-80F5-067F2C3BDD39

Figs 6D , 45–46

Etymology

This name reflects the apparent restriction of this species to the island of Dominica.

Material examined

Holotype

DOMINICA • ♂; Clarke Hall Estate; 3 Jun. 1966; G. Steyskal leg.; USNM. Paratypes

DOMINICA • 3 ♂♂; same data as for holotype; USNM • 1 ♂; Clark Hall Estate ; 2 Jun. 1966; G. Steyskal leg.; USNM • 2 ♂♂; Clarke Hall Estate ; 4 Jun. 1966; G. Steyskal leg.; USNM • 1 ♂; Clarke Hall Estate ; 11–20 Mar. 1965; W.W. Wirth leg.; USNM • 1 ♂; Clarke Hall Estate ; 13 May 1966; G. Steyskal leg.; USNM • 1 ♀; South Chiltern Estate ; 20 Feb. 1965; W.W. Wirth leg.; USNM .

Description

BODY ( Fig. 45A ). Length 1.8–2.5 mm. Head brown, lower third of frons orange; face, gena, and antennae orange-brown. Frontal width 2.4–2.5× frontal height. Three pairs of strong interfrontal bristles surmounting a very fine fourth pair; anterior orbital 0.6–0.7 × length of posterior. Palpus yellow. Eye large, greatest height about 3.5 × shortest genal height. Thorax brown, scutum with paler lateral edges. Two pairs of dorsocentral bristles (anterior pair distinct, 0.4× length of posterior pair) separated by 8–9 rows of acrostichal setulae. Membrane around prosternum bare. Legs yellow, mid and hind femora slightly darker. Fore femur with three large ventral preapical setae. Ventral surface of male mid tibia with two rows of stout setae in apical quarter. Wing ( Fig. 6D ) hyaline. CS2 0.7–0.8 × CS3. Halter pale brown.

MALE ABDOMEN ( Figs 45B–C , 46 ). Dark brown, tergites reddish medially, posterior edges of tergites slightly desclerotized. T2–5 and S2–4 uniformly long-setose with large posterolateral setae. S5 rectangular, 1.1× as long as S4, right side longer than left side, posterolaterally long setose with a very large desclerotized medial area (extending almost to anterior edge), a large, dark, rectangular, medial patch of dense but fine setulae, and a large, dark, anvil-shaped posteromedial sclerite. Anterior flange of S6+7 1.5× as long as wide; S6+7 completely separated from completely from S8. Sclerite A small, lightly sclerotized; sclerite B well developed and long, normally arched into genital pouch; sclerite C absent; sclerite D well sclerotized and L-shaped; sclerite E small, fitting into a depression in distal half of large sclerite F; sclerite G small, about as large as ring sclerite; ring sclerite well sclerotized. Epandrium large, 0.4× length of S8, height 1.4× maximum length and 0.8 × maximum width, uniformly long-setose; perianal pads weakly developed but densely setulose. Pseudocercus very small, bearing only a single seta; halves of subepandrial sclerite short and narrow, swollen where they contact subcercus and very weakly fused medially. Subcercus large and shield-like with small lobes articulating with surstylus and epandrium, apex truncate. Hypandrium with long anteromedial apodeme. Surstylus very large and broad, twice as long as deep, concave, with dense lateral setae and a setose inner basal ridge (ridge entire). Postgonite relatively short, angulate, concave ventrally, apex swollen with prominent ridges. Phallapodeme large, gradually broadened towards apex; basiphallus expanded posterodorsally with a notched central lobe and a pair of rounded, downturned lateral lobes, basal part extending ventrally as an apically flared tube-like section which articulates with distiphallus; distiphallus largely reduced with a broad dorsal sclerite and a narrow, U-shaped ventral sclerite.

FEMALE ABDOMEN. T7 broad, posteromedially shortened; T8 divided into a small, pale dorsal sclerite and two dark lateral sclerites with angulate posteroventral corner. Epiproct small, pale, and posteromedially setulose. Cercus narrow and elongate with a large apical seta and a moderate preapical seta. S7 rounded posteriorly; S8 reduced to two dark, ovoid lateral sclerites. Three spermathecae, single one larger than paired ones, bulb bean-shaped and smooth with a slight basal invagination.

Distribution

Neotropical: Dominica.

Remarks

Sclerocoelus dominicensis sp. nov. is morphologically very similar to S. irregularis sp. nov., S. pararegularis sp. nov., and S. regularis , from which it differs in having an apically truncate subcercus; females of these species seem to be indistinguishable. Sclerocoelus dominicensis is one of six species known from the Caribbean, the other five being the very widespread S. caribensis , S. rectangularis ( Malloch, 1914) , S. regularis (which occurs in Trinidad), S. dasysternum sp. nov., and S. vulgatus sp. nov. (which both occur in Tobago). All ten specimens of S. dominicensis were collected during the Bredin-Archbold-Smithsonian Biological Survey of Dominica. The female abdomen is not illustrated here as the abdomen of the only known female specimen is damaged.

Figures

Fig. 6. Sclerocoelus Marshall, 1995, left wings, ventral view. A. Sclerocoelus costaricensis sp. nov. B. Sclerocoelus cubus sp. nov. C. Sclerocoelus dasysternum sp. nov. D. Sclerocoelus dominicensis sp. nov. E. Sclerocoelus dryadalis sp. nov. F. Sclerocoelus elephas sp. nov. G. Sclerocoelus espeletia sp. nov. H. Sclerocoelus flavus sp. nov. I. Sclerocoelus frigidifrons sp. nov. J. Sclerocoelus grandicercus sp. nov. Scale bars: A–J =0.5 mm.

Fig. 45. Sclerocoelus dominicensis sp. nov. A. Male paratype habitus, lateral view. B. Male holotype terminalia, posterior view (USNM). C. Holotype left surstylus, posterior view (USNM). Abbreviations: epa= epandrium; pc=pseudocercus; sc =subcercus; se =subepandrial sclerite; ss= surstylus. Scale bars: A=1.0 mm; B=0.25 mm; C=0.20 mm.

Fig. 46. Sclerocoelus dominicensis sp. nov., male holotype (USNM). A. Aedeagus and associated structures, lateral view. B. Male S5 and genital pouch, ventral view. Abbreviations: bp =basiphallus; dp =distiphallus; hyp=hypandrium; pg = postgonite; ph =phallapodeme. Scale bars: A=0.13 mm; B=0.25 mm.