Systenus colombiensis, Ramos-Pastrana & Merchan-Vargas & Soares, 2024

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, Zootaxa 5514 (3), pp. 257-272 : 261-263

Systenus colombiensis sp. nov.

( Figs 2 , 7 )

Diagnosis. Antenna mostly dark brown, except ventral edge of scape and pedicel and dorsal and ventral edges of postpedicel at basal 1/3 orangish yellow ( Fig. 2A, B ). Postpedicel abruptly narrowed at apical 2/3, 4X longer than the highest point ( Fig. 2B ). Metepimeron brown ( Fig. 2A ). Legs yellow, except basal 2/3 of coxae II and III, It 5 and IIt 5 and tarsus III from apex of IIIt 1 brown ( Fig. 2A ). Wing hyaline ( Fig. 2D ). Surstylus slightly shorter than cercus and epandrial capsule, wide basally and abruptly narrowed at apical 1/3, with 2 long, acute digitiform processes, 1 basodorsal and 1 at apical 1/3 of ventral edge, apex of surstylus slightly curved ventrally ( Fig. 2F ).

Description. Male ( Fig. 2 ). Body length: 2.4 mm; wing 2.2 mm. Head ( Fig. 2A, B ). Similar to S. bickeli sp. nov. except as noted: Palpus yellow with short whitish yellow setae at apical 1/2. Proboscis pale brown. Antenna mostly dark brown, except ventral edge of scape and pedicel and dorsal and ventral edges of postpedicel at basal 1/3 orangish yellow; postpedicel abruptly narrowed at apical 2/3, 4X longer than widest point; arista-like stylus short, about 1/3 as long as postpedicel. One pair of strong divergent ocellar setae and 1 pair of tiny postocellar setae; 1 pair of strong proclinate vertical setae; 1 pair of paravertical about 1/2 as long as vertical setae; one row of postocular, uppermost 3 black, remaining setae pale brown; postcranium metallic green covered by silvery pruinosity. Thorax ( Figs 2A, C ). Chaetotaxy. Lower surface of proepisternum with 1 yellow whitish strong seta and upper surface with 1 thin seta. Legs ( Fig. 2A ). Yellow, except basal 2/3 of coxae II and III, It 5 and IIt 5 and tarsus III from apex of IIIt 1 brown. Leg I. Podomere ratios: 63, 59, 27/14/10/8/6. Anterior surface of coxa I covered by short vestiture of yellow setae, apical edge with 5 long yellow setae. Femur I and tibia clothed by short vestiture of yellow setae, femur I with ventral surface of basal 1/2 mostly bare. Leg II. Podomere ratios: 75, 70, 35/27/21/15/8. Anterior surface of coxa II covered by short vestiture of yellow setae, longer at apical edge. Femur II mostly clothed by short vestiture of yellow setae, basal 1/2 of ventral surface mostly bare. Tibia II with 3 pairs of antero- and posterodorsal setae at 2/6, 4/6 and apex, 1 ventral seta at apex. Leg. III. Podomere ratios: 80, 93, 17/40/25/20/9. Lateral surface of coxa III with 1 strong yellow seta near middle. Femur III mostly clothed by short vestiture of yellow setae, basal 1/2 of ventral surface mostly bare. Tibia III with 1 posterodorsal seta at basal 1/4, with row of strong dorsal setae starting at basal 1/4 and extending to apical 3/4. Wing ( Fig. 2D ). Hyaline, veins pale brown. Crossvein dm ending at basal 5/8; R 4+5 and M 1 slightly bowed at apical 6/8, ending parallel at apex; length of crossvein dm-m/last part of M 4 (“CuAx ratio”): 0.9. Abdomen ( Fig. 2E ). Mostly metallic green, covered by short vestiture of black setae, tergite 1 with long setae at posterior margin, tergite 2–5 with dorsal and lateral brown bands. Hypopygium ( Fig. 2F ). Surstylus slightly shorter than epandrial capsule, wide basally and abruptly narrowed at apical 1/3, with 2 long, acute digitiform processes, 1 basodorsal and 1 at apical 1/3 of ventral edge, apex of surstylus slightly curved ventrally, with 1 ribbon-like seta, 1 long, slender seta at middle of ventral edge. Epandrial lobe as wide as surstylus at widest point, gradually narrowed towards apex, apex curved upward, with 2 long setae, 1 basally and 1 apically. Cercus yellow, long and narrow, about 1.5X longer than surstylus, with rounded swollen base and covered by short yellow setae.

Female. Unknown. Type material. HOLOTYPE ♂,labelled:“ COLOMBIA, Caquetá, Montañita,Vda.[Vereda] Morros ,Fca.[Finca]

Las Dalias, 01º29’24’’N / 75º24’09’’W, 348 m, 29.III–09.IV.2017 / Trampa Malaise en Bosque (Suelo), Y. RamosPastrana Leg. ( LEUA)” (photographed specimen). PARATYPE: “ Idem, Belén de los Andaquíes, Vda.[Vereda]

Aletones, Fca. [Finca] La Cabaña, 01º29’31’’N / 75º52’20’’W, 369 m, 26.X–03.XI.2016 / Trampa Malaise en Bosque (Dosel) (1 ♂, LEUA)”. Holotype condition: good, abdomen dissected and stored in microvial with glycerin.

Distribution. Colombia (Caquetá: Montañita) ( Fig. 7 ).

Remarks. Systenus colombiensis sp. nov. runs to S. rarus Naglis in the key of Naglis (2000) and to S. flavifemoratus Bickel in the key of Bickel (2015) but can be differentiated from both species by the surstylus with two surstylar processes and only abruptly narrowed at apical 1/3 (one surstylar process and surstylus abruptly narrowed at apical 1/ 2 in S. rarus and S. flavifemoratus ).

Etymology. The name of the new species refers to Colombia, where the type series has been collected.

Figures

FIGURE 2. Systenus colombiensis sp. nov., holotype male (before dissection). A. Habitus, lateral view; B. Head, lateral view; C. Thorax, dorsal view; D. Right wing; E. Abdomen, dorsal view; F. Hypopygium, left lateral view.

FIGURE 7. Geographical records of Systenus Loew in Colombia. S. beatae Naglis, 2000; S. bickeli sp. nov.; S. colombiensis sp. nov.; S. flaviatus Naglis, 2000; S. fuscus sp. nov.; S. grossus sp. nov.; S. maculipennis Bickel, 2015; S. naranjensis Bickel, 2015 and S. parkeri Bickel, 2015.