Sclerocoelus costaricensis 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 costaricensis

description: Sclerocoelus costaricensis sp. nov.
urn:lsid:zoobank.org:act: 9E375286-2011-4EFF-B471-70A96EB06601
Figs 6A, 37–39
Etymology
This name reflects the apparent restriction of this species to Costa Rica, where it is widespread.
Material examined
Holotype
COSTA RICA • ♂; Alajuela, Volcán Tenorio, north slope, trail to laguna; 1000 m a.s.l.; 18 Jun. 2000; S.A. Marshall leg.; sweeping; MNCR.
Paratypes
COSTA RICA – Alajuela • 7 ♂♂, 1 ♀; same data as for holotype; DEBU • 7 ♂♂, 1 ♀; same data as for holotype; MNCR • 4 ♂♂, 2 ♀♀; Volcán Tenorio, north slope near Bijagua Biological Station; 700 m a.s.l.; 16–20 Jun. 2000; S.A. Marshall leg.; raised emergence trap over Atta mound; DEBU • 13 ♂♂, 4 ♀♀; same data as for preceding; 17 Jun. 2000; rainforest, trail sweep; DEBU • 4 ♂♂, 1 ♀; same data as for preceding; 18 Jun. 2000; sweeping trail; MNCR • 21 ♂♂, 9 ♀♀; same data as for preceding; sweep over Atta mound; DEBU • 22 ♂♂, 10 ♀♀; same data as for preceding; MNCR • 1 ♂, 1 ♀; same data as for preceding; 18–20 Jun. 2000; pans between cut leaves; DEBU • 7 ♂♂, 8 ♀♀; same data as for preceding; 18 Jun. 2000; Buck and Marshall leg.; pans in treefall; DEBU • 7 ♂♂, 8 ♀♀; same data as for preceding; MNCR • 5 ♂♂, 4 ♀♀; same data as for preceding; 19 Jun. 2000; MNCR • 5 ♂♂, 3 ♀♀; Volcán Tenorio, north slope, trail to laguna; 800–900 m a.s.l.; 18 Jun. 2000; M. Buck leg.; rainforest, sweep; DEBU • 6 ♂♂, 3 ♀♀; same collection data as preceding; MNCR. – Cartago • 1 ♂; Tapantí National Park, near west entrance, trail to hydro tower/creek; 1150 m a.s.l.; 11 Oct. 1999; Marshall and Buck leg.; sweep; DEBU • 1 ♂; Tapanti National Park, outside near west entrance; 1150 m a.s.l.; 8–9 Oct. 1999; Marshall and Buck leg.; trail sweep; MNCR. – Guanacaste • 1 ♂; Guanacaste National Park, Pitilla Station, 9 km S of Santa Cecilia; 700 m a.s.l.; 14 Feb. 1996; S.A. Marshall leg.; MNCR. – Heredia • 2 ♂♂; 6 km ENE of Vara Blanca; 10°11′ N, 84°07′ W; 2000 m a.s.l.; 21 Feb. 2002; DEBU • 1 ♂; Moravia, near border of Braulio Carrillo National Park; 3–4 Mar. 1996; L. Masner; creek bed, yellow pans; CNCI. – Puntarenas • 2 ♂♂; Braulio Carrillo National Park; 1400–1500 m a.s.l.; 11 Apr. 1985; H. Goulet and L. Masner leg.; cool moist riverbed, Selva Premontana; MNCR • 3 ♂♂; Las Alturas; 1500–1700 m a.s.l.; 12 Aug. 1995; S.A. Marshall leg.; sweep; MNCR • 1 ♂; Las Alturas; 1600 m a.s.l.; 15 Aug. 1995; S.A. Marshall leg.; ground Eciton raid; DEBU • 1 ♂; Monteverde Biological Station; 1500 m a.s.l.; 26 May 1998; S.A. Marshall leg.; sweep; DEBU • 1 ♀; Monteverde Biological Station; 1500 m a.s.l.; 13 Jun. 2000; M. Buck leg.; white pans in kitchen compost; MNCR • 1 ♂; Monteverde; 23–27 Feb. 1991; B.J. Sinclair; CNCI.
Description
BODY (Fig. 37A). Length 1.9–2.6 mm. Head dark brown, lower third of frons orange; face, gena, and antennae orange-brown. Frontal width 2.2–2.3× frontal height. Two pairs of strong interfrontal bristles surmounting a fine third pair; anterior orbital 0.5–0.6× length of posterior. Palpus orange. Eye very large, greatest height about 4.5× shortest genal height. Thorax dark brown, scutum with paler lateral edges. Two pairs of dorsocentral bristles (anterior pair only slightly larger than surrounding acrostichal setulae) separated by 6–7 rows of acrostichal setulae. Membrane around prosternum bare. Legs yellow, fore and mid tibiae 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. 6A) slightly infuscate. CS2 0.7–0.8 × CS3. Halter brown.
MALE ABDOMEN (Figs 37B–C, 38). Dark brown, posterior edges of tergites sometimes slightly desclerotized. T2–5 and S2–4 uniformly long-setose with large posterolateral setae. S5 rectangular, 1.9 × length of S4, deeply emarginate anteromedially, laterally sparsely setose with dark, square patch of dense setulae flanked by pale setose areas, and a dark, triangular, posteromedial lobe. Anterior flange of S6+7 very large, 1.2 × as long as wide, longer than S5. Sclerite A long, narrow; sclerite B broad, short, continuous with pigmented area of sclerite A; sclerite C absent; sclerite D narrow, with a short base extending along left side of posteromedial lobe of S5, and a posterior lobe similar in size and shape to sclerite E; sclerite E long but broad, flat; sclerite F large, basal part subquadrate with an elongate, apicoventral process on left side; sclerite G narrow, sinuate, slightly flattened; ring sclerite thin but dark. Epandrium small, 0.5 × length of S8, height 1.3 × maximum length and 0.7 × maximum width, uniformly setose; anal fissure rounded; perianal pads weakly developed. Pseudocercus fused to subcercus and bearing 3 setae; halves of subepandrial sclerite thin, strongly arched, expanded and broadly fused medially. Subcercus small, subtriangular with a short, narrow, posteroventral process. Hypandrium with short, thin anteromedial apodeme. Surstylus simple, circular in lateral view with basal constriction, outer surface finely setulose and flat, inner surface setose with a broad, carinate, basal lobe. Postgonite simple, flattened, slightly curved anteriorly. Phallapodeme large, apex dorsoventrally flattened; basiphallus small, with a short, dorsoventrally flattened, triangular epiphallus; distiphallus reduced, very short but very broad, with a pair of thin dorsolateral sclerites and a broad ventral sclerite.
FEMALE ABDOMEN (Fig. 39). T7 broad, simple, desclerotized anteromedially and posteromedially; T8 divided into a pale, dorsal sclerite and two large, dark, lateral sclerites, posterolateral corners greatly expanded, strongly pointed, and curved ventrally. Epiproct large, subtriangular, medially desclerotized, and setulose in posterior two-thirds. Cercus elongate, curved, apically rounded with long apical, dorsal, and apicoventral setae. S7 broad, subrectangular with four large posterior setae; S8 broad, rectangular, desclerotized, with darker lateral thirds. Hypoproct with thickened ventromedial setulae. Three spermathecae, bulb stout, somewhat conical, finely striate with a shallow basal and a deep subapical invagination, both with a small, finger-like, central process.
Distribution
Neotropical: Costa Rica.
Remarks
Sclerocoelus costaricensis sp. nov. is superficially very similar to the closely related S. dasysternum sp. nov., but differs by the darker gena, larger eye (~4.5× genal height), longer second costal sector (0.7–0.8× length of third), and single dark posteromedial patch of setulae on the male S5. Sclerocoelus costaricensis, a member of the mostly Central American S. dasysternum group, is one of four endemic Costa Rican Sclerocoelus species and one of 17 Sclerocoelus species known from Costa Rica. Six other members of the S. dasysternum group occur in Costa Rica. Several of the specimens listed above were collected in association with leafcutter ant nests, where they probably developed in the colony’s refuse deposits.
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 45-47, DOI: 10.5852/ejt.2025.979.2803, http://zenodo.org/record/14980852