Sclerocoelus lutosus Kuwahara, Marshall & Paiero, 2025, sp. nov.
Creators: name: Kuwahara, Gregory K.
name: Marshall, Stephen A.
name: Paiero, Steven M.
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Sphaeroceridae
Sclerocoelus
Sclerocoelus lutosus

description: Sclerocoelus lutosus sp. nov.
urn:lsid:zoobank.org:act: 26D008D4-3881-4CDB-A7DB-5B2B1A99AEED
Figs 7G, 81–83
Etymology
This name reflects the muddy, riparian habitats recorded for most of the type specimens (from the Latin ‘ lutosus ’, meaning ‘muddy’).
Material examined
Holotype
PERU • ♂; Cusco, 6.6 km S of Paucartambo; 13°22′49″ S, 71°36′17″ W; 3100 m a.s.l.; 13–16 May 2007; Marshall, Kits and Paiero leg.; along creek, yellow pans; MUSM debu00303223.
Paratypes
BOLIVIA – La Paz • 1 ♂, 1 ♀; 3 km E of Desaguadero, shore Lago Titicaca; 16°33′26″ S, 69°01′21″ W; 19 Apr. 2001; S.A. Marshall leg.; shoreline drift, sweeping; CBFC • 1 ♀; same data as for preceding; DEBU • 1 ♂, 2 ♀♀; Altiplano, Pillapi, 70 km E of La Paz; 3780 m a.s.l.; 8 May 1964; J.L. Chudley leg.; field of alfalfa and grass; BMNH • 2 ♂♂, 5 ♀♀; same data as for preceding; 6 Apr. 1964; swept from Esparo sp. in erosion channel; BMNH • 1 ♀; same data as for preceding; 7 May 1964; BMNH • 1 ♀; same data as for preceding; under stones in erosion valley; BMNH • 1 ♂; Lake Titicaca, W Guaqui; 16°35′56″ S, 68°53′52″ W; 3810 m a.s.l.; 19 Apr. 2001; S.A. Marshall leg.; stream, sweep; DEBU.
PERU – Cusco • 3 ♂♂; same data as for holotype; DEBU • 2 ♂♂; same data as for holotype; MUSM.
Description
BODY (Fig. 81A). Length 2.2–3.5 mm. Head dark brown, bottom edge of frons and anterior third of gena orange. Frontal width 2.3 × frontal height. Three pairs of strong interfrontal bristles surmounting a very fine fourth pair; anterior orbital 0.5× length of posterior. Palpus yellow. Eye large, greatest height about 3.5 × shortest genal height. Thorax dark brown, scutum with reddish lateral edges. Two pairs of dorsocentral bristles (anterior pair distinct, 0.8× length of posterior pair) separated by 6–7 rows of acrostichal setulae. Membrane around prosternum bare. Legs brown, hind tibia darker. Fore femur with four large ventral preapical setae. Ventral surface of male mid tibia with two rows of stout setae in apical half. Wing (Fig. 7G) slightly infuscate. CS2 subequal to CS3. Halter brown with white apex.
MALE ABDOMEN (Figs81B–C, 82).Dark brown, posterior edges of tergites sometimes slightly desclerotized. T2–5 and S2–4 uniformly long-setose with large posterolateral setae. S5 rectangular, 1.1× length of S4, long-setose with a deep posteromedial emargination. Anterior flange of S6+7 small, 0.8× as long as wide. Sclerites A to F apparently absent; sclerite G large, elongate; ring sclerite dark, well developed. Epandrium moderate, 0.7× length of S8, height 1.6 × maximum length and 0.8× maximum width, uniformly long-setose; perianal pads weakly developed. Pseudocercus absent; halves of subepandrial sclerite arched and completely separated. Subcercus large, wedge-shaped, basal section long-setose with a triangular anterior lobe, elongate posteroventral lobe slightly bent outwards with a small apical lobe. Hypandrium with long, sinuate anteromedial apodeme. Surstylus subrectangular, posteromedial margin constricted, anterolateral surface setose, apex with a claw-like inner lobe. Postgonite subtriangular, basal half broad, apical half tapered and slightly curved, apex with a small notch. Phallapodeme very large, dark, apical third curved downwards; basiphallus stout, posteriorly expanded; distiphallus large, basal third tubular and sclerotized, apical two-thirds expanded, largely membranous with a sinuate ventral sclerite, anteroapical membrane transversely grooved.
FEMALE ABDOMEN (Fig. 83). T7 broad, simple; T8 divided into a small, pale, dorsal sclerite and 2 large, broad, dark, lateral sclerites, posteroventral corners greatly expanded posteriorly. Epiproct broad, posteromedially pointed and desclerotized, and entirely setulose. Cercus elongate, spindle-shaped, with long dorsal, apical, and lateral setae. S7 very large, posteromedially pointed with four large posterior setae; S8 reduced to a pair of elongate lateral sclerites. Three spermathecae, bulb stout, cylindrical, finely striate with a shallow apical and basal invagination, each with a short, finger-like, central process.
Distribution
Neotropical: Bolivia, Peru.
Remarks
Sclerocoelus lutosus sp. nov. is externally similar to both S. caligarius sp. nov. and S. frigidifrons sp. nov., but can be separated from both species by the large anterior dorsocentral bristle, slightly larger eye (~3.5 × genal height), more uniformly setose male S5, narrow surstylus, and large lateral plates of the female T8. Like other basal species of the genus, Sclerocoelus lutosus is a high Andean species associated with decaying plant material above 3000 m a.s.l. Most records are from small deposits of debris along stream margins in otherwise relatively barren altiplano habitats.
description: Published as part of Kuwahara, Gregory K., Marshall, Stephen A. & Paiero, Steven M., 2025, A revision of the genus Sclerocoelus Marshall (Diptera: Sphaeroceridae), pp. 1-277 in European Journal of Taxonomy 979 on pages 74-75, DOI: 10.5852/ejt.2025.979.2803, http://zenodo.org/record/14980852