Microcerella desertum, Santos & Mello-Patiu & Couri & Mulieri, 2025

Microcerella desertum sp. nov.

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Figs 3–4 View Fig View Fig

Diagnosis

Male: head with 1 proclinate orbital seta; wings with vein R 1 bare or with 1–2 setae; terminalia with epandrium orange ( Fig. 4D View Fig ), basiphallus and distiphallus distinctly separated by a dorsal membranous strip ( Fig. 3D View Fig ), and vesica with a superior and inferior projection, the superior one bifurcated in ventral view and the inferior one with a pointed projection ( Fig. 3D–E View Fig ).

Etymology

The species epithet ‘ desertum ’, treated as a noun in apposition, refers to the Atacama Desert, the type locality of the new species.

Type material

Holotype CHILE • ♂, terminalia dissected and glued to a small piece of cardboard pinned under the specimen; “Chile, Atacama Prov. [Province] / 8 km N. Estancia Cas- / tilla , 30.VI.1966 / Mike E. Irwin & / Nelson Hitchins O. / Cal. Acad. Sci. Coll. [printed on white paper] // HOLOTYPE [printed on red paper] // Microcerella desertum sp. nov. / Santos, Mello-Patiu, / Couri & Mulieri 2025 [handwritten on white paper] // CASENT / 8451925 [printed on white paper]”; CASENT8451925 ; CAS.

Paratypes CHILE • 1 ♂, with left fore and mid leg glued to a small piece of cardboard and exposed terminalia; same data as for holotype; MNRJ • 1 ♂, with left fore and mid leg glued to a small piece of cardboard, right foreleg lost and abdomen dissected and stored in a microvial with glycerin pinned under the specimen; same data as for holotype; CASENT 8451940 ; CAS .

Description

Male (n = 3)

MEASUREMENTS. Length: 6–8 mm.

HEAD. Parafacial, fronto-orbital plate and postocular orbit dark brown with silvery pruinosity ( Fig. 4A– C View Fig ); facial ridge with setae on lower quarter; parafacial with sparse setulae close to eye, 2 similar in size to subvibrissal setae; frons about 0.36–0.38x head width at level of ocellar triangle; frontal vitta blackish ( Fig. 4C View Fig ); 8–12 well-developed frontal setae reaching level of apex of pedicel; rows of frontal setae parallel except anteriormost 3–6 divergent; reclinate orbital seta present, 1 proclinate orbital seta present; ocellar setae as developed as upper frontals; outer vertical seta 1.5 × as long as postocular setae; gena and genal groove with silver pruinosity ( Fig. 4C View Fig ); gena with black setae; postgena silvery-gray pruinose with black setae; antenna black ( Figs 4A, 4C View Fig ); first flagellomere approximately 2 × as long as pedicel; arista micropubescent on basal half ( Fig. 4C View Fig ); palpus blackish ( Figs 4A, 4C View Fig ).

THORAX. Dark brown with silvery pruinosity ( Fig. 4A–B View Fig ); chaetotaxy: acrostichals 0+0, dorsocentrals 3+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 apical setae present or absent, and pair of discal setae present or absent; katepisternum with 3 setae almost in straight line; meral setae 5–7; proepisternum bare.

WING. Hyaline, with dark brown veins ( Fig. 4A–B View Fig ); tegula dark brown; basicosta yellowish; vein R 4+5 with setulae dorsally at basal ⅔ of distance to crossvein r-m; vein R 1 bare or with 1–2 setae; cell r 4+5 open at wing margin; costal spine differentiated; third costal sector bare ventrally.

LEGS. Blackish-brown, pulvilli yellowish-brown ( Fig. 4A View Fig ); mid femur with 3 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 pruinosity ( Fig. 4A–B View Fig ); T4 with pair of median marginal setae and pair of lateral marginal setae; T5 with row of marginal setae; ST2–4 with marginal setae more developed than discal setae; ST5 with a membranous window, arms approximately 2.5 × of base length, and dense setae pattern ( Fig. 3A View Fig ).

TERMINALIA. Syntergosternite 7+8 and apex of phallus black, other structures orange ( Fig. 4D View Fig ); cercus with numerous setae in basal half and sparse setae in apical half; cercal prongs divergent dorsally and pointed ( Fig. 3B–C View Fig ); surstylus almost triangular, with sparse apical setae ( Fig. 3B View Fig ); pregonite slightly curved, longer than postgonite, with apex bifurcated ( Fig. 3D View Fig ); postgonite with apex rounded and curved and short seta inserted on anterior margin near base ( Fig. 3D View Fig ); postgonal apodeme long and rectangular ( Fig. 3D View Fig ); basiphallus and distiphallus distinctly separated by dorsal membranous strip ( Fig. 3D View Fig ); vesica with superior and inferior projection, superior one bifurcated in ventral view and inferior one with pointed projection ( Fig. 3D–E View Fig ); juxta distinctly separated from paraphallus ( Fig. 3D View Fig ); acrophallus formed by median stylus, median process, and pair of lateral styli ( Fig. 3D–E View Fig ); median stylus almost straight in lateral view, median process tubular and lateral stylus with conspicuous spines in apex ( Fig. 3D–E View Fig ).

Female

Unknown.

Remarks

Microcerella desertum sp. nov. is morphologically similar to M. spinigena (Rondani, 1864) . These species can be separated by the single proclinate orbital seta present in the male of M. desertum , which is absent in M. spinigena , as well as by the cercal prong being shorter than the base of the cercus, and juxta with an apical margin forming lobes in M. desertum ( Fig. 3B–E View Fig ), whereas in M. spinigena the cercal prong is longer than the base of the cercus, and juxta with straight apical margin ( Mulieri et al. 2015: figs 187–188, 190).

Distribution

Chile (Atacama).