Metatrichia barbata, Ale-Rocha & Limeira-De-Oliveira, 2021

Ale-Rocha, Rosaly & Limeira-De-Oliveira, Francisco, 2021, New species and new record of Neotropical Metatrichia Coquillett (Diptera: Scenopinidae), Zootaxa 5039 (1), pp. 119-128 : 120-122

Metatrichia barbata sp. nov.

( Figs 1–4 , 13–14 )

Diagnosis. Mouth opening surrounded ventrally by dense thin elongate yellow setulae. Thorax covered by dense, evenly distributed, scale-like setae; dark brown to black with a dark yellow dot on postpronotal lobe; yellow, thin, elongate setulae inserted between scale-like setae on notopleuron and upper portion of katepisternum. Legs dark brown. Wing with cream-white infuscation, veins pale yellow; knob of halter white. Abdomen dark brown with lateral and distal margin of tergites yellow, with dense scale-like setae on lateral margins of T2–3 and throughout T4–T7; sternites yellow with sublateral pale brown stain and with scale-like setae on lateral margin, except T1 black and bare.

Description. Holotype ♂. Body length: 5.25 mm. Head. Ocellar tubercle protuberant, bearing dense scale-like setae. Frons shiny black, linear dorsally for a long distance, about 1.5 times the length of ocellar tubercle, lacking scale-like setae; lower frons completely covered with scale-like setae. Scale-like setae feather-shape and yellow. Parafacial mostly yellow. Antenna with scape black, pedicel and flagellum dark yellow; short fine pale brown setae on distal margin of scape and pedicel, flagellum covered by minute inconspicuous scale-like yellow setae. Buccal pieces well developed; palpus black, very slender and pointed distally, with yellow slender elongate conspicuous setae over entire lateral surface. Occiput black, bare; occipital margin lacking scale-like setae. Gena black with fine, elongate and dense yellow setae, denser and longer ventrally around buccal margin. Thorax black with a pale brown to yellow dot on postpronotal lobe and dark yellow postalar callus. Scutum and scutellum covered with dense, evenly distributed scale-like feather-shape setae, silver white laterally and yellowish dorsally, except postalar callus without scale-like setae and two narrow, short, acrostichal bare stripes, slightly divergent posteriorly, in the presutural region. Scutellum with deep preapical transverse groove. Anepisternum with dense scale-like setae and katepisternum with scale-like setae on anterior half; remaining portions of pleura lacking scale-like setae. Setae yellow, thin, elongate inserted between scale-like setae on notopleuron and upper portion of katepisternum. Anepimeron with dorsal portion yellowish with horizontal yellow whitish protrusion. Legs dark brown. Wing with cream-white infuscation, veins pale yellow; halter with white knob. Abdomen flattened dorsoventrally; dark brown with distal margin and lateral of tergites 3–7 yellow, yellow portion of tergites increasing in width towards apex of abdomen and T7 with distal half yellow; sternites yellow with sub-lateral pale brown stain, except T1 black. Tergites with dense scale-like silver white setae on lateral margins of T2 and T3 and throughout T4–T7; sternites with scale-like setae on lateral margin, except T1 and T8 bare; T1 with long, slender, yellow lateral setae. Terminalia. Epandrium band-like, not covering gonocoxites ventrally; epandrial lamellae with truncate, strongly sclerotized process on posteromedial margin; cerci elongate, directed posteriorly, with inner lateral margin folded longitudinally; hypoproct longer than cerci and spatulate; gonocoxal apodeme long and broad in ventral view; gonocoxite with short medially directed process bearing some diminute setae apically; gonostylus rounded and broadened apically, directed medially; hypandrium not distinctly fused to gonocoxite, in two long, clavate, medially directed processes; distiphallus long, broad, bifurcating arms divergent with elongate narrowed apex, in ventral view; ventral apodeme with anterior margin deeply split medially; ejaculatory apodeme large, spatulate.

Female. Unknown.

Etymology. The specific name is derived from the Latin barba (beard) and refers to the hairy aspect of the mouth opening of this species.

Comments. This species shares a set of features with M. robusta Kröber, 1913 , such as abdomen bearing scale -like setae and legs homogeneously brown to black. The lack of information on the male terminalia of M. robusta makes its distinction from other species somewhat difficult, and misidentifications have occurred as a result ( Winterton & Woodley 2009). Unfortunately, the type of M. robusta , a specimen from Paraguay, has been destroyed and all records of this species outside the country of origin are considered uncertain ( Winterton & Woodley 2009). Based on the description of Kröber (1913), M. barbata sp. nov. can be distinguished from M. robusta by the pattern of spots on the abdomen, wing coloration and body size, as presented in the identification key in this paper. Additionally, the presence of elongated and conspicuous thin bristles at the ventral margin of the mouth opening was not reported in the description of M. robusta and could represent one more character to help distinguish between these two species.

Type material. Holotype ♂. Brasil, Amazonas , Manaus, ZF –2, Km 14, 2°35’21”S - 60°06’55”W, 13–31.iii.2018, Malaise gde (grande), 32 m alt (altura), poente, J.A. Rafael – Rede Bia ( INPA).

Paratype. Brasil, Amazonas , Manaus, ZF –2, Km 14, 2°35’21”S - 60°06’55”W, 13–31.iii.2018, Malaise gde (grande), 24 m alt (altura), poente, J.A. Rafael – Rede Bia (1♂, INPA) .

Figures

FIGURES 1–4. Metatrichia barbata sp. nov.. Male: 1, habitus, lateral view; 2, head, anterior view; 3, scutum, dorsal view; 4, habitus, dorsal view.

FIGURES 13–14. Metatrichia barbata sp. nov.. Male terminalia, ventral and dorsal view. Abbreviations: e, epandrium; ea, ejaculatory apodeme; ga, gonocoxal apodeme; gs, gonostylus; va, ventral apodeme. Scale lines: 0.3 mm.