Sclerocoelus nitidistylus 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 nitidistylus

description: Sclerocoelus nitidistylus sp. nov.
urn:lsid:zoobank.org:act: 8D08C8DB-566E-4603-A1ED-8E009E135A15
Figs 1A, 8B, 96–98
Etymology
This name refers to the shining outer surface of the male surstylus (from the Latin ‘ nitidus ’, meaning ‘shiny, polished’).
Material examined
Holotype
COSTA RICA • ♂; Puntarenas, Los Alturas trail to Cerro Chai; 1700–2100 m a.s.l.; 13–15 Aug. 1995; S.A. Marshall leg.; MNCR.
Paratypes
COSTA RICA – Alajuela • 2 ♂♂; Quesada, Albergue Pozo Verde; 1800 m a.s.l.; 10°15′15.1″ N, 84°22′18.4″ W; 21 Apr. 2023; S.A. Marshall leg.; from refuse pile under Eciton burchellii bivouac; DEBU • 2 ♂♂; same data as for preceding; MNCR • 2 ♂♂, 3 ♀♀; same data as for preceding; W. Porras leg.; MNCR. – Cartago • 1 ♂; Braulio Carrillo National Park; 500 m a.s.l.; 10 Apr. 1985; L. Masner leg.; rainforest; CNCI • 1 ♀; Braulio Carrillo National Park; 1400–1500 m a.s.l.; 11 Apr. 1985; H. Goulet and L. Masner leg.; cool moist riverbed, Selva Premontana; CNCI. – Guanacaste • 3 ♂♂, 4 ♀♀; Guanacaste National Park, Cacao Field Station; 1000–1100 m a.s.l.; 12–15 Feb. 1996; S.A. Marshall leg.; carrion traps; DEBU • 1 ♀; same data as for preceding; 700 m a.s.l.; 13–15 Feb. 1996; MNCR • 2 ♂♂; Guanacaste National Park, Cacao Field Station; 1100–1200 m a.s.l.; 15 Feb. 1996; S.A. Marshall leg.; MNCR • 1 ♂; Guanacaste National Park, Santa Rosa Station; 300 m a.s.l.; 11 Feb. 1996; S.A. Marshall leg.; dry riverbed; MNCR. – Heredia • 4 ♀♀; 6 km ENE of Vera Blanca; 10°11′ N, 84°07′ W; 2000 m a.s.l.; 21 Feb. 2002; DEBU • 1 ♂, 1 ♀; Moravia, near border of Braulio Carrillo National Park; 3–4 Mar. 1996; L. Masner leg.; creek bed, yellow pans; DEBU. – Puntarenas • 6 ♂♂; Monteverde Biological Reserve; 1500 m a.s.l.; 13 Jun. 2000; S.A. Marshall leg.; DEBU • 6 ♂♂, 3 ♀♀; same data as for preceding; MNCR • 1 ♂; same data as for preceding; M. Buck leg.; DEBU • 9 ♂♂, 3 ♀♀; same data as for preceding; 11–13 Jun. 2000; cloud forest; DEBU • 10 ♂♂, 4 ♀♀; same data as for preceding; MNCR • 10 ♂♂, 3 ♀♀; same data as for preceding; S.A. Marshall leg.; DEBU • 11 ♂♂, 3 ♀♀; same data as for preceding; MNCR • 1 ♀; same data as for preceding; 12 Jun. 2000; M. Buck leg.; on dung; DEBU • 50 ♂♂, 19 ♀♀; same data as for preceding; 11 Jun. 2000, M. Buck leg.; sweep; DEBU • 51 ♂♂, 19 ♀♀; same data as for preceding; MNCR • 8 ♂♂; same data as for preceding; 12–13 Jun. 2000; pans along stream; DEBU • 6 ♂♂; same data as for preceding; 13–14 Jun. 2000; pans along stream; MNCR • 1 ♂; same data as for preceding; 14 Jun. 2000; treefall sweep and pans; DEBU • 7 ♂♂, 4 ♀♀; same data as for preceding; 26 May 1998; S.A. Marshall leg.; sweep; DEBU • 13 ♂♂; Monteverde Biological Station, lower trail; 26 May 1998; S.A. Marshall leg.; MNCR • 1 ♂, 1 ♀; Monteverde; 10°18′ N, 84°48′ W; 1539 m a.s.l.; 24 Feb.–2 Mar. 1988; B. Hubley leg.; 1° tropical cloud forest, pan traps; ROME • 1 ♂; Monteverde, Pension Queteal; 10°18′ N, 84°49′ W; 24 May 1987; Norrbom and Max leg.; DEBU • 1 ♂, 2 ♀♀; Monteverde; 1500 m a.s.l.; 11–18 Jul. 1983; D.H. Lindeman leg.; fruit pitfall; CNCI • 1 ♂; Monteverde; 1500 m a.s.l.; 29 Feb. 1988; Mason and Wood leg.; rainforest; DEBU • 2 ♂♂; Monteverde; 1500–1800 m a.s.l.; 24–27 Feb. 1991; B.J. Sinclair leg.; trail sweep; DEBU • 2 ♂♂, 2 ♀♀; Monteverde; 1520 m a.s.l.; 15–23 Jul. 1983; D.H. Lindeman leg.; flight-intercept trap; CNCI • 1 ♂, 1 ♀; Monteverde; 23–27 Feb. 1991; B.J. Sinclair leg.; DEBU • 2 ♂♂; Monteverde, Finca Canada; 1500 m a.s.l.; 28 May–1 Jun. 1988; B.V. Brown leg.; treefall, Malaise trap DEBU • 3 ♂♂; Monteverde; 25 Feb. 1991; H. and A. Howden leg.; flight-intercept trap; DEBU • 1 ♂; Monteverde; 25 May 1998; S.A. Marshall leg.; sweep near Biological Station; DEBU. – San José • 1 ♂; San Gerardo de Dota; 2300 m a.s.l.; 9 Aug. 1995; S.A. Marshall leg.; sweep along forest stream; MNCR • 1 ♂; San Gerardo de Dota; 9°33′ N, 83°48′ W; 2400–2600 m a.s.l.; 8–9 Aug. 1996; S.A. Marshall leg.; near trail; DEBU • 1 ♀; San Gerardo de Dota, near Lodge; 9°33′ N, 83°48′ W; 2000 m a.s.l.; 9 Aug. 1995; S.A. Marshall leg.; stream in pasture, sweep; DEBU.
Other material examined
COSTA RICA – Guanacaste • 1 ♂; Area de Conservacion Guanacaste, Derrumbe; 10°55′45″ N, 85°27′51″ W; 1220 m a.s.l.; 12 Feb. 2015; D.H. Janzen and W. Hallwachs leg.; forest, Malaise trap; BIOUG32728-A03/ GMCDQ410-17 sequenced for CO1-5’; BIOUG.
Description
BODY (Figs 1A, 96A). Length 2.2–3.4 mm. Head dark brown, lower half of frons, gena, face, and antennae orange. Frontal width 2.3–2.4 × frontal height. Two pairs of strong interfrontal bristles surmounting a fine third pair; anterior orbital 0.4–0.5 × length of posterior. Palpus yellow. Eye very large, greatest height about 5.0× 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 7–8 rows of acrostichal setulae; prescutellar acrostichal setulae only slightly larger than others. Membrane around prosternum bare. Legs yellowish-brown, base of fore femur paler. Fore femur with three large ventral preapical setae. Ventral surface of male mid tibia with two rows of stout setae in apical third. Wing (Fig. 8B) slightly infuscate. CS2 0.7–0.8× CS3. Halter pale brown.
MALE ABDOMEN (Figs96B–C, 97).Dark brown, posterior edges of tergites sometimes slightly desclerotized. T2–5 and S2–4 uniformly long-setose with large posterolateral setae. S5 rectangular, 1.8× length of S4, laterally sparsely setose with a dark, narrow, ventrally projecting patch of dense setulae flanked by pale setose areas. Anterior flange of S6+7 large, 2.0× as long as wide. Sclerite A dark, unmodified; sclerite B reduced to an indistinct filament arising from posterolateral corner of sclerite A; sclerite C broad but reduced and indistinct, arising from anterolateral corner of sclerite A; sclerite D well sclerotized, Y-shaped and bent distally; sclerite E dark, elongate, and slightly curved; sclerite F large, laterally concave, left side with an elongate apicoventral process; sclerite G small, dark, narrowly separated from sclerite F; ring sclerite small, dark. Epandrium moderate, 0.3 × length of S8, height 1.4× maximum length and 0.7× maximum width, uniformly setose, posteroventral margin deeply emarginate; anal fissure rounded; perianal pads weakly developed. Pseudocercus large, bearing three setae, and fused to posteroventral corners of epandrium; halves of subepandrial sclerite strongly arched, slightly flattened dorsally, and completely separate. Subcercus large, projecting posteriorly, elongate, apically bilobed, anteriorly with a short, dark, basal lobe. Hypandrium with Y-shaped anteromedial apodeme. Surstylus large, subtriangular, laterally concave and shining, inner surface setulose along a broad medial ridge and a dark carinate anterobasal lobe. Postgonite short, apically truncate and expanded, and posterolaterally crenulate. Phallapodeme very large, thick, apex dorsoventrally flattened; basiphallus small, tapered with a distinct, triangular epiphallus; distiphallus largely membranous.
FEMALE ABDOMEN (Fig. 98). T7 broad, slightly emarginate posteromedially; T8 divided into a small, pale dorsal sclerite and a pair of large, dark lateral sclerites, posteroventral corners pointed. Epiproct shield-like, medially pale, apically tapered and setulose. Cercus elongate, slightly tapered with long apical and dorsal setae. S7 broad, rounded, broadly and deeply desclerotized posteromedially with four large posterior setae; S8 a single small but well-developed sclerite. Three spermathecae, bulb spherical, finely striate with a small apical invagination and a deep basal invagination.
Distribution
Neotropical: Costa Rica.
Remarks
Sclerocoelus nitidistylus sp. nov. is similar to other members of the S. dasysternum group, but can be readily distinguished by the very shiny outer surface of the surstylus, almost beak-shaped subcercus, and the female S7 with a deep, semicircular posterior desclerotized area. Sclerocoelus nitidistylus is commonly collected in the cloud forests of Costa Rica, where it is one of four endemic Costa Rican Sclerocoelus species and one of the seven members of the S. dasysternum group found in Costa Rica.
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 82-84, DOI: 10.5852/ejt.2025.979.2803, http://zenodo.org/record/14980852