Sclerocoelus riparius 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 riparius

description: Sclerocoelus riparius sp. nov.
urn:lsid:zoobank.org:act: B17308FF-26F3-4EF6-BFCD-7886877D4637
Figs 9C, 128–130
Etymology
This name reflects the riparian habitat that many of the type specimens of this species have been collected from (from the Latin ‘ riparius ’, meaning ‘that inhabits the banks or rivers, riparian’).
Material examined
Holotype
ECUADOR • ♂; Pichincha, Cotopaxi National Park, Quebrada Mishahuaycu; 3600 m a.s.l.; 25 Oct. 1999; S.A. Marshall leg.; under streamside vegetation; QCAZ debu00108976.
Paratypes
ECUADOR – Carchi • 2 ♂♂, 2 ♀♀; Guandera Forest Reserve, 15 km E of San Gabriel; 3400 m a.s.l.; 1 Nov. 1999; S.A. Marshall leg.; hand; QCAZ • 1 ♀; same data as for preceding; sweep forest trail. – Napo • 1 ♂; near Lago Papallacta; 3400 m a.s.l.; 4–8 Nov. 1999; S.A. Marshall leg.; forest above lake, pans/ dung; DEBU • 1 ♂, 2 ♀♀; Quito-Baeza pass; 4000 m a.s.l.; 6 Nov. 1999; S.A. Marshall leg.; roadside ditch, green leaves of branches touching ground; QCAZ • 1 ♀; Quito-Baeza Road; 4000 m a.s.l.; 10–18 Feb. 1983; L. Masner leg.; pan traps in open paramo; DEBU • 1 ♂; Quito-Baeza Road; 4100 m a.s.l.; Mar. 1983; H. Tituana leg.; pan traps in paramo; DEBU. – Loja • 1 ♀; Podocarpus National Park, Cajanuma, Bosque Nublado trail; 3000 m a.s.l.; 16–20 Feb. 2009; M. Pollet and A. De Braekeleer leg.; yellow pans; RBINS. – Pichincha • 1 ♀; Campamento Pichan, near Nono; 24 Oct. 1999; S.A. Marshall leg.; sweep; QCAZ • 1 ♀; Cotopaxi National Park, Lago Limpiopungo; 3800 m a.s.l.; 25 Oct.–8 Nov. 1999; S.A. Marshall leg.; shore, pan traps; QCAZ • 2 ♂♂; Cotopaxi National Park, Quebrada Mishahuaycu; 3600 m a.s.l.; 25 Oct. 1999; S.A. Marshall leg.; near stream, pan traps; QCAZ. – Zamora-Chinchipe • 1 ♀; San Francisco Biological Reserve, Canal trail; 3°58′30″ S, 79°04′25″ W; 2000 m a.s.l.; 18–25 Feb. 2009; M. Pollet and A. De Braekeleer leg.; yellow pan traps; RBINS.
Description
BODY (Fig. 128A). Length 3.2–5.3 mm. Head dark brown, lower quarter of frons and face yellow; anterior quarter of gena and antenna orange. Frontal width 2.0–2.1× frontal height. Three pairs of large interfrontal bristles surmounting a fine fourth pair; anterior orbital 0.6–0.7 × length of posterior; several setulae present at bases of interfrontal and orbital setae. Palpus yellow. Eye large, greatest height about 3.5× shortest genal height. Thorax dark brown, scutum 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, foreleg paler. Fore femur with three large ventral preapical setae. Dorsal surface of mid tibia with a small pair of setae at about ⅓, a large anterior seta just above ½ and a large pair of setae at about ¾. Ventral surface of male mid tibia with two rows of stout setae along apical half. Wing (Fig. 9C) slightly infuscate. CS2 subequal to CS3. Halter dark brown.
MALE ABDOMEN (Figs 128B–C, 129). Dark brown, posterior edges of tergites sometimes slightly desclerotized. T2–5 and S2–4 uniformly long-setose with large posterolateral setae. S5 large, trapezoidal, 1.5× length of S4, posterolaterally long-setose, posteromedial area with two wide, pale areas and a broad patch of mixed setae (long, thin setae and shorter, thick setae). Anterior flange of S6+7 small, triangular 1.0× as long as wide. Sclerite A pale, indistinct from S6+7; sclerite B broad, arched and fused to sclerite A; sclerite C dark, C-shaped, fused to right side of sclerite A; sclerites D and E fused (?), forming a broad, dark, diamond-shaped, posteromedial sclerite; sclerite F large, broad, rounded, entirely setulose; sclerite G reduced, almost circular, fused to sclerite F; ring sclerite well developed. Epandrium small, 0.4× length of S8, height 1.6× maximum length and 0.8 × maximum width, uniformly long-setose; perianal pads weakly developed. Pseudocercus fused to epandrium and bearing a single seta; halves of subepandrial sclerite gently arched, completely separate. Subcercus large, triangular in lateral view, apical third curved backwards. Hypandrium with long, bisinuate anteromedial apodeme. Surstylus large, yellow-brown, subtriangular with a triangular, inner, anterobasal lobe, apical half with long ventral setae. Postgonite elongate, apical two-thirds bent at about a right angle to basal third, tapered, apex truncate. Phallapodeme long, apical third bent downwards; basiphallus large, boxy with a small posterodorsal epiphallus; distiphallus large, entirely membranous.
FEMALE ABDOMEN (Fig. 130). T7 broad, simple, posteromedially desclerotized; T8 divided into a large, pale, triangular, dorsal sclerite and two large, dark, lateral sclerites, posterolateral corners greatly expanded and rounded. Epiproct large, subrectangular, medially split, and setulose around bases of setae. Cercus elongate, apically rounded with long apical, dorsal, and apicoventral setae. S7 broad, posterior third desclerotized with four large posterior setae; S8 divided into two dark, teardrop-shaped, lateral sclerites. Hypoproct strongly pointed anteriorly with thickened ventral setulae. Three spermathecae, bulb stout, gumdrop-shaped, finely striate with large subbasal and apical invaginations, both with a small, finger-like, central process.
Distribution
Neotropical: Ecuador.
Remarks
Sclerocoelus riparius sp. nov. is superficially very similar to S. altus sp. nov., but differs by the bicoloured gena, male S5 with posteromedial row of thickened setae, and mostly straight postgonite. Like other basal species of the genus, Sclerocoelus riparius is a high Andean species associated with decaying plant material above 3000 m. 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 104-105, DOI: 10.5852/ejt.2025.979.2803, http://zenodo.org/record/14980852