Sclerocoelus grandicercus, 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 : 61-62

Sclerocoelus grandicercus sp. nov.

urn:lsid:zoobank.org:act:E1D8EB53-CCF3-4A48-AFB7-F85A3D19E4DA

Figs 6J, 61–63

Etymology

This name refers to the enlarged pseudocercus of this species, which are much broader than those of any other species of Sclerocoelus (from the Latin ‘ grandis ’, meaning ‘large, grand’).

Material examined

Holotype

COSTA RICA • ♂; Cartago, Tapantí National Park, La Esperanza del Guarco ; 9°42′00″ N, 83°51′49″ W; 2700 m a.s.l.; 17–18 Aug. 2001; S.A. Marshall leg.; oak forest, treefall pans; MNCR debu00203263.

Paratypes

COSTA RICA – Cartago • 1 ♂, 1 ♀; same data as for holotype; DEBU • 1 ♀; Tapantí, Macizo de la Muerte National Park, La Esperanza del Guarco ; 9°42′00″ N, 83°51′49″ W; 2700 m a.s.l.; 17–18 Aug. 2001; M. Buck leg.; oak forest, yellow pan traps; DEBU • 2 ♀♀; Tapantí, Macizo de la Muerte National Park, La Esperanza del Guarco ; 17–18 Aug. 2001; S.A. Marshall leg.; MNCR . – Heredia • 1 ♂; Braulio Carrillo National Park, Barva Biological Station ; 16 Feb. 2003; S.A. Marshall leg.; sweep downed bromeliads; DEBU . – Puntarenas • 1 ♂; Monteverde Reserve ; 1500 m a.s.l.; Feb. 1980; W. Mason leg.; cloud forest; MNCR .

Description

BODY ( Fig. 61A). Length 3.3–4.6 mm. Head dark brown, lower fifth of frons and gena yellow; face and antennae orange. Frontal width 2.2 × frontal height. Two pairs of strong interfrontal bristles surmounting a fine third pair; anterior orbital 0.4× length of posterior. Palpus yellow. Eye very large, greatest height about 4.5× shortest genal height. Thorax 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 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. 6J) slightly infuscate. CS2 0.8 × CS3. Halter brown.

MALE ABDOMEN ( Figs 61B–C, 62). Dark brown, posterior edges of tergites sometimes slightly desclerotized. T2–5 and S2–4 uniformly long-setose with large posterolateral setae. S5 rectangular, 1.4× length and 1.1× width of S4, laterally setose, posteromedially emarginate with a dark, densely setulose, Y-shaped posteromedial lobe flanked by pale areas and dark setose patches. Anterior flange of S6+7 large, 1.5 × as long as wide. Sclerite A dark, setulose, separated from S6+7; sclerite B thin, dark, elongate, and arched; sclerite C indistinct; sclerite D elongate, projecting posteriorly from left side of posteromedial lobe of S5; sclerite E short, elongate, similar to and projecting parallel to sclerite D; sclerite F large, subquadrate with an elongate apicoventral lobe on left side angulate to main part; sclerite G dark, elongate, posteriorly fused to sclerite F; ring sclerite small, dark. Epandrium moderate, 0.5× length of S8, height 1.5× maximum length and 0.8× maximum width, uniformly setose; anal fissure rounded; perianal pads weakly developed. Pseudocercus large, fused to posteroventral corners of epandrium, and bearing three setae; halves of subepandrial sclerite very broad and flat apically, strongly arched, and separate. Subcercus subquadrate in lateral view with a triangular posteroventral lobe and a small, slightly curved posterodorsal lobe. Hypandrium with thin, Y-shaped anteromedial apodeme. Surstylus simple, elongate, apically rounded, slightly curved posteriorly, densely setulose laterally with a small, dark, anterodorsal lobe. Postgonite elongate, sinuate, flattened, distally expanded and striate. Phallapodeme large, thick; basiphallus small, with a small, dorsoventrally flattened, triangular epiphallus, distally expanded and extending along dorsal margin of distiphallus; distiphallus large, dorsoventrally flattened, with long, divergent, sinuate dorsolateral sclerites and shorter ventrolateral sclerites.

FEMALE ABDOMEN ( Fig. 63). T7 broad, simple; T8 divided into a pale, dorsal sclerite and two large, dark, lateral sclerites, posterolateral corners slightly expanded and pointed. Epiproct large, subtriangular, anteromedially desclerotized, and entirely setulose. Cercus elongate, apically pointed with long apical, dorsal, and apicoventral setae. S7 broad, broadly desclerotized posteriorly with four large posterior setae; S8 divided into two dark, lateral sclerites. Hypoproct with thick anteromedial setulae. Three spermathecae, bulb stout, spherical, finely striate with deep invaginations at both ends, basal invagination with a small, finger-like, central process.

Distribution

Neotropical: Costa Rica.

Remarks

Sclerocoelus grandicercus sp. nov. is superficially similar to S. dasysternum sp. nov., from which it can be readily separated by larger size (3.3–4.6 mm), larger eye (~4.5× genal height), longer second costal sector (0.8× length of third), double patch of dark posteromedial setulae on the male S5, slightly tapered postgonite, and narrowly connected female S8. Sclerocoelus grandicercus and its probable sister species S. recurvatus sp. nov. are sympatric in the montane Quercus forests of Costa Rica. They are among the four endemic Costa Rican Sclerocoelus species and among the seven members of the S. dasysternum group found in Costa Rica.