Sclerocoelus inornatus, 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 : 63-64

Sclerocoelus inornatus sp. nov.

urn:lsid:zoobank.org:act:94FE87A5-FC8D-485B-A408-08BEE7948661

Figs 7A , 64–65

Etymology

This name refers to the inornate male S5, which is simple and unmodified compared to most other species of Sclerocoelus (from the Latin ‘ inornatus ’, meaning ‘unadorned, undecorated’).

Material examined

Holotype

ECUADOR • ♂; Pichincha, Maquipucuna Biological Reserve ; 1200 m a.s.l.; 27–29 Oct. 1999; S.A. Marshall leg.; compost pan traps; QCAZ debu00111727.

Paratype

ECUADOR – Pichincha • 1 ♂; same data as for holotype; DEBU debu00111726 .

Description

BODY ( Fig. 64A ). Length 2.9–3.0 mm. Head dark brown, ventrolateral corners of frons and part of interfrontal plate orange; gena reddish-brown. Frontal width 2.2–2.3× frontal height. Three pairs of large interfrontal bristles surmounting a fine fourth pair (holotype has a fourth large interfrontal bristle on one side); anterior orbital 0.5–0.6× length of posterior. Palpus pale brown. Eye slightly reduced, greatest height about 2.5× shortest genal height. Thorax dark brown, scutum with slightly paler lateral edges. Two pairs of dorsocentral bristles (anterior pair distinct, 0.6× length of posterior pair) separated by 6–7 rows of acrostichal setulae. Membrane around prosternum bare. Legs brown, femora darker. Fore femur with three large ventral preapical setae. Dorsal surface of mid tibia missing small anterior seta in distal half. Ventral surface of male mid tibia with two rows of stout setae along apical third. Wing ( Fig. 7A ) slightly infuscate. CS2 0.9–1.0 × CS3. Halter brown.

MALE ABDOMEN ( Figs64B–C , 65 ).Dark brown, posterior edges of tergites sometimes slightly desclerotized. T2–5 and S2–4 uniformly long-setose with large posterolateral setae. S5 rectangular, 1.2× length of S4, simple, uniformly long-setose in posterior half.Anterior flange of S6+7 undeveloped. Sclerite A indistinct from S6+7; sclerites B–F absent; sclerite G small, weakly developed; ring sclerite weakly developed. Epandrium small, 0.5× length of S8, height 1.8× maximum length and 1.0 × maximum width, uniformly setose; anal fissure large, ovoid; perianal pads weakly developed. Pseudocercus entirely membranous and bearing 2 setae; halves of subepandrial sclerite poorly developed. Subcercus bulging with 3–4 posterior setae and a flat, curved, ventral lobe. Hypandrium with long, sinuate anteromedial apodeme. Surstylus short, rectangular but concave, with several posterior and ventral setae, anteroventral corner slightly flared outwards. Postgonite short, stout, rhombic with a slight apical notch. Phallapodeme long with a subapical swelling; basiphallus stout, wedge-shaped with a short epiphallus; distiphallus moderate, largely membranous with a small dorsal sclerite and a much larger, sinuate, ventral sclerite.

FEMALE ABDOMEN. Female unknown.

Distribution

Neotropical: Ecuador.

Remarks

Sclerocoelus inornatus sp. nov. has an unmodified male S5 and the genital pouch is simple, with only a single free sclerite (presumably sclerite G). These are probably plesiomorphic states for the genus but the structure of the subcercus and associated sclerites is similar to the structure of more derived clades with a separate pseudocercus and subcercus and suggest that this species is closely related to the high alpine species S. alpinus sp. nov. and S. puyensis sp. nov. Sclerocoelus inornatus further differs from these two species by the smaller eye (~2.5 × genal height), slightly shorter second costal sector (0.7–0.8× length of third), and the small, quadrate surstylus. The low elevation type locality (1200 m) contrasts with the habitats of other basal lineages of the genus.

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. 64. Sclerocoelus inornatus sp. nov. A. Male holotype habitus, lateral view (debu00111727). B. Holotype left surstylus, posterior view (debu00111727). C. Male holotype terminalia, lateral view (debu00111727).Abbreviations: epa= epandrium; pc=pseudocercus; sc =subcercus; ss= surstylus. Scale bars: A=1.0 mm; B–C =0.25 mm.

Fig. 65. Sclerocoelus inornatus sp. nov., male holotype (debu00111727). A. Aedeagus and associated structures, lateral view. B. Male S5 and genital pouch, ventral view. Abbreviations: bp =basiphallus; dp =distiphallus; epi= epiphallus; pg = postgonite; ph =phallapodeme. Scale bars: A=0.13 mm; B=0.25 mm.