Sclerocoelus alpinus 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 alpinus

description: Sclerocoelus alpinus sp. nov.
urn:lsid:zoobank.org:act: F98C8FAD-D3B4-4AB9-9AB0-E3ECBE0D0F02
Figs 5B, 13–15
Etymology
This name reflects the high-altitude habitats from which this species has been collected (from the Latin ‘ alpinus ’, meaning ‘alpine (of/relating to/inhabiting mountains)’).
Material examined
Holotype
ECUADOR • ♂; Pichincha, 10 km NW of Quito, Valley near Hosteria San Jorge; 3050 m a.s.l.; 23 Oct. 1999; S.A. Marshall leg.; stream debris; QCAZ debu00111277.
Paratypes
ECUADOR – Carchi • 1 ♂; 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; DEBU • 2 ♂♂, 3 ♀♀; Paramo El Angel, 24 km NW of El Angel; 3800 m a.s.l.; 3 Nov. 1999; S.A. Marshall leg.; dung traps in moss; QCAZ. – Loja • 1 ♂; Podocarpus National Park, Cajanuma, Bosque Nublado trail; 3000 m a.s.l.; 19 Feb–5 Mar. 2009; M. Pollet and A. De Braekeleer leg.; Malaise trap; debu00194781 / MYRO919-21 sequenced for CO1-5’; RBINS. – Pichincha • 7 ♂♂, 11 ♀♀; same data as for holotype; QCAZ • 2 ♀♀; Cotopaxi National Park, Quebrada Mishahuaycu; 3600 m a.s.l.; 25 Oct. 1999; S.A. Marshall leg.; under streamside vegetation; DEBU • 1 ♂; 10 km NW of Quito, valley near Hosteria San Jorge; 3050 m a.s.l.; 22–25 Oct. 1999; S.A. Marshall leg.; creek bed, pan traps; QCAZ • 1 ♂, 2 ♀♀; same data as for preceding; 23 Oct. 1999; stream valley sweeping; DEBU.
VENEZUELA – Mérida • 4 ♂♂; 6 km S of Azulita, near road; 3 May 1988; S.A. Marshall leg.; DEBU • 5 ♂♂, 5 ♀♀; S Bolivar National Park, near La Aguada; 3000 m a.s.l.; 13 May 1981; L. Masner leg.; DEBU. – Trujillo • 2 ♂♂, 4 ♀♀; Boconó, road to Guaramacal; 2570 m a.s.l.; 2 Mar. 1996; S.A. Marshall leg.; creek bed; DEBU • 2 ♀♀; Boconó-Guaramacal Road; 3000 m a.s.l.; 3 Mar. 1995; S.A. Marshall leg.; wet debris along spring; DEBU.
Description
BODY (Fig. 13A). Length 2.6–4.1 mm. Head dark brown, lower third to half of frons and antenna orange; face and gena orange-brown. Frontal width 2.4–2.5 × frontal height. Three pairs of strong interfrontal bristles surmounting a very fine fourth pair; anterior orbital 0.6–0.7× length of posterior. Palpus pale brown. Eye large, greatest height about 3.5× shortest genal height. Thorax dark brown, scutum with slightly paler lateral edges; postpronotum and anterior edge of anepisternum pale. 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, foreleg paler. Fore femur with four large ventral preapical setae. Dorsal surface of mid tibia with a small pair of setae at about ⅓, a large anterior seta at ½ and a large pair of setae at about ¾. Ventral surface of male mid tibia with two rows of stout setae along apical third. Wing (Fig. 5B) slightly infuscate. CS2 subequal to CS3. Halter brown.
MALE ABDOMEN (Figs 13B–C, 14). Dark brown, posterior edges of tergites sometimes slightly desclerotized. T2–5 and S2–4 uniformly long-setose with large posterolateral setae. S5 large, rectangular, 1.2× length of S4, uniformly long-setose with a pair of long posteromedial setae surrounded by a broad, pale, densely setulose strip. Anterior flange of S6+7 not developed. Sclerite A large, pale, densely setulose; sclerite B long, arched; sclerite C absent; sclerite D large, asymmetrically triangular; sclerites E and F fused into a large, triangular sheet wrapping around right side of sclerite A; sclerite G large, pale; ring sclerite weakly sclerotized. Epandrium small, wedge-shaped, 0.6× length of S8, height 1.4 × maximum length and 0.8 × maximum width, uniformly long-setose; anal fissure moderate, rounded; perianal pads weakly developed. Pseudocercus and subanal plate absent; halves of subepandrial sclerite weakly arched, medially fused. Subcercus slender, curved and blade-like distally; basally with a broad outer lobe bearing three large setae. Hypandrium with anteromedial apodeme long and straight, hypandrial arms thick and arched. Surstylus stout, subquadrate with long setae (longest on anterior and ventral edges) and a triangular, anteroapical inner lobe. Postgonite short, basal half broad, apical half strongly tapered and gently curved. Phallapodeme long, slightly curved; basiphallus elongate, slightly curved with a stout, upcurved epiphallus; distiphallus short, membranous with a strongly bent dorsal sclerite, a broad ventral sclerite, and a pair of sinuate lateral sclerites; dorsoapical membrane transversely rugose.
FEMALE ABDOMEN (Fig. 15). T7 broad, simple; T8 divided into a pale, almost entirely membranous dorsal sclerite and two large, dark, lateral sclerites, posterolateral corners slightly expanded but broadly emarginate. Epiproct large, subtriangular, strongly tapered in apical third, anteromedially desclerotized, and entirely setulose. Cercus elongate, apically pointed with long apical, dorsal, and apicoventral setae. S7 subtriangular/T-shaped, desclerotized along posterior margin with four large posterior setae; S8 entirely membranous. Hypoproct entirely setulose with several small dorsolateral setae. Three spermathecae, bulb stout, spherical, largely smooth with shallow invaginations basally and subapically, both with a small, finger-like, central process.
Distribution
Neotropical: Ecuador, Venezuela.
Remarks
Sclerocoelus alpinus sp. nov. can be separated by from other species of Sclerocoelus by the long male S5, relatively small male genitalia, strongly tapered postgonite, and Y- or T-shaped female S7. Sclerocoelus alpinus is among several congeners associated with wet vegetation, especially along waterways, in the high Andes. We have collected it repeatedly in wet vegetation on the margins of alpine streams at altitudes from 2500 to 3400 m a.s.l. The elongate, ventrally narrow and curved subcercus of this species resembles that of S. inornatus sp. nov. but, unlike S. inornatus, S. alpinus has a complex genital pouch with multiple discrete sclerites as in the related S. altus sp. nov., S. puyensis sp. nov., and S. punensis sp. nov.
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 23-24, DOI: 10.5852/ejt.2025.979.2803, http://zenodo.org/record/14980852