Apotropina longicerci sp. nov.

(Figs 1–8, 25–26)

Diagnosis. Postpedicel brown on upper ¾, yellow on lower ¼ in external surface (Fig. 1); fore coxa dark yellow, darker posteriorly (Fig. 1); all legs with basal apex of femur and tibia yellow, tibial organ narrow, yellow, ~ 3× shorter than hind tibial length, hind tibial spur indistinct (Fig. 1); surstylus widened in profile (Fig. 5); male cercus more than 2× longer than wide, with a curved seta longer than surstylus length (Figs 7–8).

Description. MALE (holotype). Body length 3.4 mm. Wing length 4 mm. Body dark brown with ochre pruinosity. Head (Figs 1–2). Wider than long dorsally and longer than high in profile. Ocellar seta as long as inner and outer vertical setae. Postocellar seta cruciate, ~ ⅔ the length of ocellar seta. Three strong fronto-orbital setae, the anterior seta ~ ½ the length of the posterior setae, the two posterior setae ~ each equal to length of the ocellar seta; the anterior fronto-orbital seta proclinate, the two posterior fronto-orbital setae lateroclinate. Inner vertical seta proclinate, outer vertical seta lateroclinate. Frons dark brown basally, apical ¼ yellow, slightly wider than long, lateral margins diverging posteriorly to ocellar triangle, apical margin sinuous. Ocellar triangle extending to ~ ⅔ length of frons, posterior margin nearly as wide as frons, lateral margins straight, apex acute. Eye oval, long axis slightly oblique. Face pale yellow, about as high as wide; postpedicel rounded, brown on upper ¾, yellow on lower ¼ in external surface; arista dark brown, with short, sparse pubescence, as long as ½ frons; genal height equal to height of postpedicel, with whitish pruinosity; one vibrissa; occiput and postgena dark brown; proboscis brown; palpus yellow with black setulae; clypeus darkened. Thorax (Figs 1, 3). Scutum dark brown, ~ 1.2× longer than wide, pruinose; postpronotal lobe concolorous with scutum, with two long setae equal in length to notopleural setae; 1+1 notopleural setae; 5 strong dorsocentral setae, prescutellar dorsocentral seta ~ 2× longer than remaining dorsocentral setae; pleuron with grey pruinosity; katepisternun with pale setulae. Scutellum concolorous with scutum, with black pilosity, apical scutellar seta ~ 3× longer than subapical scutellar seta. Halter stem brown, knob pale yellow. Wing (Fig. 4). Brown infuscate; costal ratios measured from h: R 1: R 2+3: R 4+5 is 4: 5: 3.5: 1.8; veins R 4+5 and M 1 subparallel; distance between r-m and dm-m 4.5× length of r-m. Legs (Fig. 1). Dark brown; fore coxa dark yellow, darker posteriorly; fore and mid trochanters yellow; all legs with anterior apex of femur, tibia and first tarsomere yellow; tibial organ narrow, yellow, ~ 3× shorter than hind tibia length (Fig. 1); hind tibial spur indistinct. Abdomen (Fig. 1). Tergites dark brown. Terminalia (Figs 5–8). Postabdominal sclerites asymmetric; syntergosternite 7+8 about as long as hypandrium; sternite 6 curved, as wide as sternite 5, with a lobe on inner margin medially; sternite 5 curved, wider medially, tapering to extremes, ~ 5× longer than wide. Epandrium brown, fusiform in profile, with brown pilosity, without laterobasal projection; subepandrial sclerite V-shaped, base narrower than cerci; surstylus with apical half yellow and with short, yellow setae, base slightly narrower than epandrial in profile, apex broad and round; cercus at least 2× longer than wide, with curved setae ~ 1.5× as long as surstylus, cerci basally fused; anal lobe indistinct. Hypandrium with arms closed; basiphallus slightly oval, as long as distiphallus; distiphallus sclerotized ventrally; pre- and postgonite equal in length; sperm pump indistinct.

FEMALE. Unknown.

Type material. HOLOTYPE ♂, deposited in LEUA: COLOMBIA, Caquetá, Florencia, Vda.[Vereda] Sucre, 01º52′12″N / 75º40′09″W, 2292 m [eters], 26–28.Sep [IX].2023, Y. Ramos-Pastrana Leg. / Captura con trampa Malaise colocada a nivel de un sistema lótico (al aire) / (LEUA-67440). PARATYPE: same data as holotype (1 ♂ LEUA-67441).

Etymology. The specific epithet refers to “Latin, longus, meaning long + cerci, referring to the genitalic structure; a noun in apposition; in reference to the long cerci in the male”.

Geographical occurrence. Colombia (Caquetá, Florencia) (Fig. 25).

Habitat. The specimens were collected in a Malaise trap placed over a creek in the low montane rainforest with dense secondary vegetation in the Andean-Amazonian transition corridor of Colombia (CAM 2018) (Fig. 26).