Corethrella xokleng, Amaral & Mariano & Pinho, 2019

Amaral, André P., Mariano, Rodolfo & Pinho, Luiz Carlos, 2019, Four new species and some new records of Brazilian frog-biting midges (Diptera Corethrellidae), Zootaxa 4706 (1), pp. 103-120 : 110-112

Corethrella xokleng sp. n.

( Figures 3–5 )

Type material. Holotype, male adult, slide mounted: “HOLÓTIPO Corethrella xokleng Amaral, Mariano & Pinho ♂, Grão Pará, SC, BR, Rio Três Barras #11, S28º12’44” W49º27’28”, 15.XI.2012, light trap, LC Pinho, LS Gomes & AL Schlindwein”, ( MZUSP) . Allotype, adult female, slide mounted, as holotype, except: “ALÓTIPO Corethrella xokleng Amaral, Mariano & Pinho ♀, Rio Braço Esquerdo #17, S28º09’01” W49º21’21”, 16.XI.2012 ” ( MZUSP) . Paratype: 1 adult female, slide mounted, as allotype ( UFSC) .

Etymology. The specific epithet honors the Xokleng people, the original inhabitants of the type location, who have been brutally decimated since the beginning of colonization by those of European extraction in southern Santa Catarina state. The name is to be regarded as a noun in apposition.

Diagnostic characters. This species differs from other extant Corethrella by the following combination of characters: Adult male: trochanter and base of hind femur paler than apex of femur, 3rd palpal segment clavate (apically expanded), 4 thick setae on frons, empodia thick, with 10 bifid branches. Adult female: Wings and legs uniformly pigmented, head rounded in dorsal view, 3rd palpal segment clavate (apically expanded), four thick setae on frons, empodia thick, with 10 bifid branches.

Description. Adult male (n=1). ( Tables 1 , 2 , Figs. 3 , 4 A–D)

Head ( Fig. 3A ). Rounded in anterior view. Coronal suture long, reaching ventral margin of eye bridge. Four parallel thick setae on frons. Palpus ( Fig. 4A ) medium brown, with 3rd segment somewhat expanded apically, 5 th segment with about double the length of 4th. Clypeus ( Fig. 4B ) square with three setae on dorsal surface. Antenna (as in Fig. 4H ) brown with flagellomere 13 apically bifurcated. Sensilla coeloconica distributed according to table 1.

Thorax ( Fig. 3B ). Light to medium brown, with mesonotum darker, anepimeron with one seta, pale with central portion more darkly pigmented. Posterior anepisternum with incomplete diagonal suture at ventral margin. Anterior anepisternum divided in half by transversal suture. Prescutal suture long, almost reaching dorsocentral row of setae. Group of five setae on posterior portion of dorsocentral row. Katepisternum pale around ventral margin.

Wings (as in Fig. 3B ). Plain brown, with setae instead of scales on non-marginal veins. Vein R 1 somewhat bolder. Apex of R 2 basal to the one of M 1. Halter slightly lighter or same color than scutellum.

Legs ( Fig. 3B ). Uniformly medium brown, except midleg trochanter, lighter than femur and trochanter, base of hind femur lighter than apex of femur. Legs without scales. Tarsal claws equal, inserted apically. Empodia (as in Fig. 4C ) thicker than apical setae of last tarsomeres, longer than average diameter of last tarsomeres, with 9–10 bifid branches.

Abdomen. Uniformly medium to dark brown.

Genitalia ( Figs. 3C , 4C, D ). Gonocoxite ( Fig. 3C ) medium to dark brown, elongate, slender; dorsal row with five setae, the first slightly thinner than the rest. 5th seta medially dislocated; one dorsomedial thicker seta, tapering from midlength. Gonostylus with constant width subtly bent subapically, with apical seta very short and thick. subbasal seta located posteroventrally at 0.2 of gonostylus, length about 0.3 of gonostylus. Aedeagus ( Fig. 4C ) long, strongly tapering from base; margins fused near apex.

Adult female: (n=2) ( Tables 1 , 2 , Figs. 4 E–H, 5) as for male, except:

Head ( Fig. 5A ). Coronal suture short, ending close to dorsal margin of eye bridge. Palpus ( Fig. 4F ) with 3rd segment clavate. Clypeus ( Fig. 4G ) with 6–8 setae on dorsal surface. Sensilla coeloconica distributed according to table 1.

Abdomen ( Fig. 5D ). Medium to dark brown. Cercus equally pigmented.

Immatures. Unknown.

Distribution and biology. This species is known from three individuals (two females and one male) collected in light traps from type locality, Serra Furada State Park, in Grão Pará, SC, at elevations of 355– 354 m. Serra Furada is a region of Atlantic Forest, interspersed with large areas of Eucalyptus cultivation, near the transition to Araucaria Forest at higher altitudes. The rivers where traps were set are gravel-bed streams, 4–6m wide and about 1m deep.

Taxonomic discussion. This species shares the synapomorphies which define the rotunda group (as designated by Borkent, 2008): wings without a pattern of pigmentation and posterior anepisternum with contiguous ventral and dorsal portions. Male flagellomere 8 shorter than both 7 and 9, wing with apex of R 2 basal to apex of M 1 and the presence of setae instead of scales on wing veins place Corethrella xokleng sp. n. among the clade formed by C. kerrvilensis (Stone), C. remiantenalis Borkent, C. blandafemur Borkent , C. brevivena Borkent , and C. globosa Borkent. Corethrella xokleng sp. n. does not share the synapomorphies that group C. remiantenalis with C. blandafemur or C. brevivena with C. globosa , respectively, suggesting it may be the sister to a clade comprised of all four of these species. Females and males of C. xokleng sp. n. were associated by their shared pigmentation patterns on wings and legs, the collecting location, the pattern of empodia and by the 4 setae on the frons, the latter being a unique character among rotunda group.

Figures

FIGURE 3. Corethrella xokleng sp. n., adult male.A, head in anterior view. B, thorax in lateral view. C, tergites 7–9 and genitalia.

FIGURE 4. Corethrella xokleng sp. n., adult male (A–D) and female (E–H). A, palpus. B, clypeus. C, aedeagus. D, 9th tergite, gonocoxite and gonostylus in dorsal view. E, tarsal claw and empodium. F, palpus. G, clypeus. H, antennal flagellum.

FIGURE 5. Corethrella xokleng sp. n., adult female. A, head in anterior view. B, thorax and legs in lateral view. C, wing. D, abdomen in ventral view.