Mesoconius acca, Marshall, 2019

Marshall, Stephen A., 2019, A revision of the genus Mesoconius Enderlein (Diptera, Micropezidae, Taeniapterinae), European Journal of Taxonomy 548, pp. 1-126 : 53-56

Mesoconius acca sp. nov.

urn:lsid:zoobank.org:act:63EA4FD8-711C-4848-9EAE-D16008F66BC3

Figs 20–21

Etymology

The species name is derived from the acronym for the Asociación para la Conservación de la Cuenca Amazónica (ACCA) because most of the type specimens are from the ACCA field station at Wayqecha. This is also a welcome opportunity to honour an organization that has done so much to protect Peruvian biodiversity and to facilitate documentation of that biodiversity while training the next generation of Amazonian conservationists.

Material examined

Holotype

PERU • ♂; Cusco, Wayqecha Biological Station , 9 km NE of Challabamba; 13°10ʹ20ʺ S, 71°35ʹ00ʺ W; 2600–2700 m a.s.l.; 1–6 Dec. 2011; S.A. Marshall leg.; MUSM.

Paratypes

BOLIVIA • 1 ♂; La Paz, Coroico, Cerro Uchumachi ; 16°12ʹ43ʺ S, 67°42ʹ49ʺ W; 2550 m a.s.l.; 5 Apr. 2001; S.A. Marshall leg.; cloud forest; MYCRO456 sequenced for CO1; CBFC .

PERU • 4 ♂♂, 1 ♀; same collecting data as for holotype; DEBU • 1 ♀; Piches and Perené River valleys; 610–915 m a.s.l.; Soc. Geog. de Lima leg.; one hind leg on body, one hind leg in vial, no other legs; ANSP • 1 ♀; Charape River ; 14 Nov. [probably 1909–14]; C.H.T. Townsend leg.; USNM .

Description

LENGTH. 20 mm.

COLOUR. Head black to dark brown, except for silvery gena, parafacial and middle of face, yellow palpus, narrow anterior strip on T3, yellow fore tarsus, yellow hind tarsomeres 1–2 and variable red or yellow parts on coxae, femora and tibiae. Frontal vitta velvety black, subantennal areas shiny brown. Wing strongly infuscated, with large and distinct clear areas in cell r 2+3, cell r 4+5, and distal to crossvein dm-cu. Oviscape dark brown basally, black distally.

HEAD. Epicephalon and paracephalon finely striate, subshining, slightly more shiny than orbits; frontal vitta posteriorly tapered to a broad, densely golden-microtrichose patch extending to inner vertical bristles; broad and broadly tapered anteriorly, not reaching frons margin.Antennae separated by width of antennal socket, upper face strongly and broadly carinate; parafacials, lower face flat and microtrichose. Clypeus shiny medially, laterally microtrichose.

THORAX. Cervical sclerite with a vertical groove separating a microtrichose, subquadrate posterior portion from a small, bare anterior portion. Fore tibia broad, sulcate on outer face. Postpronotal lobe microtrichose, with some scattered small setulae, anterior margin forming a vertical, shiny face.

ABDOMEN. Abdominal segment 1 petiolate; length of 1+2 double that of tergite 3.

FEMALE ABDOMEN. Bursa small and weakly differentiated, ventral receptacle not noted; spermathecal ducts arising independently from truncate apex of bursa; common duct of paired spermathecae long and broad, divided into distinct parts, including a long, rugose basal part and a narrow, smoother distal part. Paired spermathecae large, tapered to base and ringed by deep transverse striae; each on a separate long stem that is slightly swollen on basal half and deeply sinuate on distal half. Single spermatheca elongate, no wider than duct; duct very short, about 0.3× length of paired duct, with a short constricted area at base.

MALE ABDOMEN. Sternites 5 and 6 lightly sclerotized, small. Sternite 7 dark, with a broad anterior apodeme and an expanded, bare, spatulate right apex. Sternite 8 black, anterior margin shiny, otherwise dull, microtrichose. Epandrium with prominent, setose posteroventral angles, cercus large and distinct. Postgonites small and divergent (directed laterally), with four small apical setae. Basal part of distiphallus broadly tubular, gradually expanding to a very large phallic bulb forming a distinctive broad hood over base of distal part of distiphallus. Ejaculatory apodeme slightly larger than epandrium.

Remarks

Mesoconius acca sp. nov. is similar to M. infestus and thus part of a diverse species complex of similarly robust flies with bright orange and black legs, heavily infuscated wings with diffuse distal clear spots and a dark brown to black face. Leg and abdominal colours vary widely within these species. M. acca sp. nov. is distinguished from M. infestus by its mostly microtrichose black male S8 (in contrast to the bare and shiny S8 that characterizes M. infestus ), the swollen and extensively pigmented mid femur, and its significantly larger size. As in many other species of Mesoconius , M. acca sp. nov. varies widely in leg colour, most often with a single-banded mid femur and a double-banded hind femur.

Figures

Fig. 20. Mesoconius acca sp. nov., external appearance. A, D–E. Living ♂♂, Wayqecha Biological Station, Peru. B. Head. C. Part of pleuron to show swollen katatergite.

Fig. 21. Mesoconius acca sp. nov., internal characters, Peru. A. Abdomen, ♂. B. Male terminalia. C–D. Phallic bulb and adjacent parts of distiphallus, left (C) and right (D) views. E–F. Spermatheca and associated structures. Abbreviations: bdp = basal distiphallus; ddp = distal distiphallus; e = epandrium; hy = hypandrium.