Microcerella obscura Santos, Mello-Patiu, Couri & Mulieri, 2025, sp. nov.

Microcerella obscura sp. nov. urn:lsid:zoobank.org:act: 781F2D21-1598-4DF0-A826-5610248E772D Figs 1–2 Diagnosis Male: head without proclinate orbital setae; wings with vein R 1 setulose; terminalia with epandrium orange (Fig. 2D), basiphallus and distiphallus distinctly separated by a dorsal membranous strip (Fig. 1C), and vesica with a superior and inferior projection, the inferior one with a serrated margin (Fig. 1C–D). Etymology The species epithet ‘ obscura ’, from Latin and treated as an adjective, refers to the dark phallic structures. Type material Holotype ARGENTINA • ♂, terminalia dissected and stored in a microvial with glycerin; “Argentina:Pr. [Province] Catamarca / Cuesta Minas Capillitas / 3000m Pastizal J.L.Neff / #refers to host & date. [printed on white paper] // 84573 [printed on white paper] // Collection of the / CALIFORNIA ACADEMY / OF SCIENCES San / Francisco Calif. [printed on white paper] // Microcerella / sp. / T. Pape det. 1987 [handwritten, with T. Pape det. printed] // HOLOTYPE [printed on red paper] // Microcerella obscura sp. nov. / Santos, Mello-Patiu, / Couri & Mulieri 2025” [handwritten on white paper] // CASENT / 8451106 [printed on white paper]”; CASENT8451106; CAS. Description Male (n = 1) MEASUREMENTS. Length: 9 mm. HEAD. Parafacial, fronto-orbital plate and postocular orbit dark brown with silver pruinosity (Fig. 2A– C); facial ridge with few setae on lower ¼; parafacial with row of setulae close to eye, similar in size to subvibrissal setae; frons about 0.27 × head width at level of ocellar triangle; frontal vitta blackish (Fig. 2B–C); 7–9 well-developed frontal setae reaching level of apex of pedicel; rows of frontal setae parallel except anteriormost 3 divergent; reclinate orbital seta present, proclinate orbital setae absent; ocellar setae as developed as upper frontals; [outer vertical seta broken]; gena and genal groove with silvery pruinosity (Fig. 2A, C); gena with black setae; postgena silvery-gray pruinose with black setae; antenna black (Fig. 2A, C); first flagellomere approximately 1.5 ×as long as pedicel; arista short pubescent on basal half (Fig. 2C); palpus blackish (Fig. 2A, C). THORAX. Dark brown with silver pruinosity (Fig. 2A–B); chaetotaxy: acrostichals 0 +? [pin inserted in the middle], dorsocentrals 2+3, intra-alars 1+2, supra-alars 1+3, postpronotals 3, notopleurals 4; postalar wall bare; postalar callus with 2 setae; scutellum with pair of basal and pair of subapical setae, pair of discal setae and without apical setae; katepisternum with 3 setae almost in straight line; meral setae 5; proepisternum bare. WING. Hyaline, with dark brown veins (Fig. 2A–B); tegula dark brown; basicosta yellowish; vein R 4+5 with setulae dorsally at basal ⅔ of distance to crossvein r-m; vein R 1 setulose; cell r 4+5 open at wing margin; costal spine differentiated; third costal sector bare ventrally. LEGS. Blackish-brown, pulvilli yellowish-brown (Fig. 2A); mid femur with 2 median anterior setae, row of anteroventral setae, 2 preapical posterior setae, row of posteroventral setae, and without ctenidium; mid tibia with 2 median anterior setae, 2 median posterior setae and 2 posterior setae in apical third; hind trochanter without ventromedian pad of short, spiniform setae. ABDOMEN. Dark brown with silvery-gray pruinosity and slightly yellowish pruinosity laterally (Fig. 2A); T4 with pair of median marginal setae and pair of lateral marginal setae; T5 with row of marginal setae; ST2–4 with marginal setae slightly more developed than discal setae; ST5 with membranous window, arms approximately 2.5 × of base length, and dense setae pattern. TERMINALIA. Syntergosternite 7+8 and apex of phallus black, other structures orange (Fig. 2D); cercus with numerous long setae in basal half and short and sparse setae in apical half; cercal prongs divergent dorsally and rounded (Fig. 1A–B); surstylus clavate, with long apical setae (Fig. 1B); pregonite straight, almost same length as postgonite (Fig. 1C); postgonite with apex pointed and curved and a short seta inserted on anterior margin near base (Fig. 1C); postgonal apodeme short and rectangular (Fig. 1C); basiphallus and distiphallus distinctly separated by dorsal membranous strip (Fig. 1C); paraphallus with ventro-apical projection (Fig. 1C); vesica with superior and an inferior projection, inferior one with serrated margin (Fig. 1C–D); juxta distinctly separated from paraphallus (Fig. 1C–D); acrophallus formed by median stylus, median process, and pair of lateral styli (Fig. 1C–D); median stylus almost straight, median process tubular and lateral stylus curved (Fig. 1C–D). Female Unknown. Remarks Microcerella obscura sp. nov. is morphologically similar to M. austrohartigia Pape, 1990, and M. multidentata (Lopes, 1981). These three species can be separated by the configuration of the serrated margin of the inferior projection of the vesica, which in M. obscura has different-sized serrations and is inserted almost in a straight line (Fig. 1C–D), in M. multidentata it also has different-sized serrations but is inserted in a pointed projection (Lopes 1981: figs 60–61), and in M. austrohartigia it has similar-sized serrations and is inserted almost in a straight line (Lopes 1981: figs 46–49). Distribution Argentina (Catamarca).