Systenus bickeli Ramos-Pastrana, Merchan-Vargas & Soares, 2024, sp. nov.
Creators: name: Ramos-Pastrana, Yardany
name: Merchan-Vargas, Geraldine Lucia
name: Soares, Matheus M. M.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Dolichopodidae
Systenus
Systenus bickeli

description: Systenus bickeli sp. nov.
(Figs 1, 7)
Diagnosis. Antenna dark brown, except ventral surface of scape, pedicel, and basoventral subtriangular area of postpedicel orange-yellow; postpedicel abruptly narrowing at apical 1/2, 4X longer than high as highest point (Fig. 1A, B). Metepimeron grayish brown (Fig. 1A). Legs yellow, except apical 1/4 of coxae II and III, tarsus II and III from apex of basitarsus dark brown (Fig. 1A). Wing light brown (Fig. 1D). Surstylus wide at basal 1/3 and abruptly narrowing at apical 2/3, slightly curved ventrally at apex, with 1 long and acute basodorsal digitiform process, about as long as the width of surstylus at base (Fig. 1F). Cercus long, digitiform, about 1.5X longer than surstylus (Fig. 1F).
Description. Male (Fig. 1). Body length: 3.2 mm; wing 2.8 mm. Head (Fig. 1A, B). Face narrowed below, narrower than ocellar tubercle; clypeus short, rectangular, ending above lower eye margin; face, clypeus and frons metallic green and covered by silvery pruinosity. Palpus pale brown with short black setae at apical 1/2 and 1 strong, black apical seta (shorter than palpus). Proboscis brown. Antenna dark brown, except ventral surface of scape, pedicel and basoventral subtriangular area of postpedicel; postpedicel abruptly narrowed at apical 1/2, 4X longer than high at widest point; arista-like stylus broken off. Ocellar setae lost, 1 pair of tiny postocellar setae; vertical setae lost; 1 pair of short paravertical setae; one row of postocular, uppermost 6 black, remaining setae pale brown; postcranium metallic green and covered by silvery pruinosity. Thorax (Fig. 1A, C). Mostly metallic light green with weak bluish reflections and coppery acrostichal stripe ending close to scutellum, thorax wholly covered by silvery pruinosity. Pleura grayish brown, with weak greenish and bluish reflections. Metepimeron grayish brown. Chaetotaxy. Pronotum with row of strong, yellow setae; lower surface of proepisternum with 1 light brown strong seta and upper surface with 1 thin, light brown seta; 2 regular rows of acrostichals setae ending between fourth and fifth posterior dorsocentrals; 6 strong dorsocentrals; 1 pre-, 1 sutural and 1 postsutural intra-alars; 1 pre-, and 2 postsutural supra-alars; 1 strong and 1 tiny postpronotal; 2 notopleurals; 1 postalar; 1 pair of strong medial and 1 pair of short lateral scutellar setae. Legs (Fig. 1A). Yellow, except apical 1/4 of coxae II and III, tarsus II and III from apex of basitarsus dark brown. Leg I. Podomere ratios: 80, 78, 37/25/17/?/? (It 4–5 broken off). Anterior surface of coxa I covered by short vestiture of yellow setae, 4 long yellow setae at apical edge. Femur I clothed by short vestiture of brown setae, except ventral surface mostly bare. It 4–5 lost. Leg II. Podomere ratios: 90, 91, 50/45/30/20/10. Anterior surface of coxa II covered by short vestiture of yellow setae, longer at apical edge. Femur II mostly clothed by short vestiture of black setae, except ventral surface with pale setae. Tibia II with 1 dorsal and 1 posterior seta at basal 1/4, and crown of setae at apex: 1 anteroventral, 1 ventral, 1 posterodorsal and 1 dorsal seta. Leg. III. Podomere ratios: 98, 110, 25/55/33/23/12. Lateral surface of coxa III with 1 strong, yellow seta near middle. Femur III clothed by short vestiture of brown setae, except ventral surface mostly bare. Tibia III with dorsal row of slightly longer, thicker setae, starting at basal 1/4 and ending before near apex. Wing (Fig. 1D). Light brown, veins brown. Costal ending at M 1; R 1 ending at basal 3.5/8; dm ending at basal 5.5/8; R 2+3 nearly straight; R 4+5 and M 1 slightly bowed at apical 6.5/8, ending nearly parallel sided at apex; CuA+CuP as indistinct fold, length of crossvein dm-m/last part of M 4 (“CuAx ratio”): 0.7. Halter whitish yellow. Abdomen (Fig. 1E). Mostly metallic green, covered by short vestiture of black setae, tergite 1 with long setae at posterior margin, tergites 2–5 with dark brown dorsal band, tergites 6–7 entirely dark brown, tergite 7 long and setose, forming long peduncle with sternite 7, sternite 8 brown. Hypopygium (Fig. 1F). Surstylus about as long as epandrial capsule, wide at basal 1/3 and abruptly narrowed at apical 2/3, slightly curved ventrally at apex, 1 long, acute basodorsal digitiform process, about as long as width of surstylus at base, 2 short and 1 long setae at basal 1/3 of ventral edge, a few short setae at dorsal and ventral edges before apex, and 1 ribbon-like seta at apex. Epandrial lobe as wide as surstylus at widest point, gradually narrowed at apex, nearly straight, only slightly curved ventrally at apex, with 1 short basal and 1 long apical seta. Cercus yellow, long and narrow, about 1.5X longer than surstylus and epandrial capsule, with rounded swollen base, and covered by short yellow setae.
Female. Unknown.
Type material. HOLOTYPE ♂, labelled:“ COLOMBIA, Caquetá, Florencia, Vda.[Vereda] Sucre, 01º51’04’’N / 75º40’01’’W, 1719 m, 29.III–14.IV.2017 / Trampa Malaise en Bosque (Dosel), Y. Ramos-Pastrana Leg. ” (LEUA)
(photographed specimen). Holotype condition: good, right leg I and left It 4–5 broken off, abdomen dissected and stored in microvial with glycerin.
Distribution. Colombia (Caquetá: Florencia) (Fig. 7).
Remarks. The new species runs to S. beatae in the key of Naglis (2000) and to S. flavifemoratus in the key of Bickel (2015), but can be differentiated from S. beatae by the surstylus shorter than cercus and abruptly narrowed at apical 2/3 and by the presence of 1 long, acute basodorsal digitiform process (surstylus longer than cercus, only slightly narrowed at apex, with 1 wide digitiform process at middle of dorsal edge in S. beatae) and from S. flavifemoratus by the wing light brown and the surstylus slightly curved ventrally at apex (wing hyaline and surstylus abruptly curved ventrally at apex in S. flavifemoratus).
Etymology. Named after Daniel Bickel (Australian Museum) for his contribution to the knowledge of the genus Systenus.
description: Published as part of Ramos-Pastrana, Yardany, Merchan-Vargas, Geraldine Lucia & Soares, Matheus M. M., 2024, First record of the genus Systenus Loew (Diptera: Dolichopodidae) from Colombia, with description of four new species, pp. 257-272 in Zootaxa 5514 (3) on pages 259-261, DOI: 10.11646/zootaxa.5514.3.3, http://zenodo.org/record/13849826