Mesembrinella bullata Whitworth & Yusseff-Vanegas 2019, sp. nov.

Abstract

Mesembrinella bullata Whitworth, sp. nov. (Figs 67–68, 157–158, 221, 264, 308, 352, 393, 437, 473, 488) Diagnosis. A small fly averaging 9.4 mm (9–10/5) in length. Thorax, subshining dark blue and abdomen shiny bluepurple, both covered with whitish tomentum; ppn bluish with 3x 3 setae; wing hyaline; disc of T5 with some fairly stout, disorganized setae, more or less at middle of disc. Epandrium, cerci and surstyli distinctive: cerci in posterior view with broad basal half and sharply narrowed in distal half (Fig. 68). Female terminalia as in Fig. 308. Description. Male. Head. Frons broad, 0.09 (0.08–0.09/2) of head width at narrowest, almost as broad as width of first flagellomere; fronto-orbital pale with whitish tomentum; lower half of frontal vitta orange, upper half black, frontal vitta significantly narrowed midway; fronto-orbitals broad, frontal setae ascending about 65% of distance to vertex; parafacial pale orange. Gena with horizontal row of 3–4 stout, black setae and a few sparse short setae, anterior 1/2–2/3 of gena orange, posterior 1/2–1/3 with dense silvery tomentum; postgena with silvery tomentum and covered with pale, silky setae; occiput black with silvery tomentumand dense, silky golden setae; median occipital sclerite with silvery tomentum in upper third, lower 2/3 subshining black; palpus typical; pedicel and first flagellomere orange; eye with median facets slightly larger than lateral facets; ocellar triangle small, anterior ocellus 1/3 larger than posterior ocelli; supravibrissal setae dark brown, ascending about 1/5 of distance to antennal base. Thorax. Dorsum and pleural area of thorax dark blue with silvery tomentum, and with faint pale presutural tomentose stripes [some specimens]; chaetotaxy: ac 2:1, dc 2:3, ia 0, ph 1, ppn 3x 3, kat 1:1, meral setae in unusual pattern, in straight line, row with slight bend anteriorlyabove, 1 pair of crossed ap, sa absent, 2 lat, 1 stout bas, 1 pb weak, 1 disc; subscutellum weakly developed; spiracles medium-sized, brown to yellow-brown; legs entirely dark brown with tips of femora orange. Wing hyaline, faintly yellow, veins darker at base, basal cells faintly darkened; subcostal sclerite bare; basicosta tan with pale setae, tegula brown; section IV 0.13 of section III; calypters with tan discs and brown rims with brown setae. Abdomen purple, subshining, with pale tomentum; T1+2 and T3 each with a pair of lateral marginal setae; T4 with row of stout, erect marginal setae on posterior margin; T5 disc with some fairly stout, unordered setae together with dense, short, fine setae. Terminalia in lateral view with surstylus very short, slightly curved backward, cercus much longer (Fig. 67); in posterior view, basal half of cerci bulbous, distal half abruptly narrowing to tip (Fig. 68); phallus in lateral view: base of epiphallus broad with moderate backward curve (Fig. 157); in dorsal view, hypophallic lobes narrow (Fig. 158); T6, STS7+8, pre- and postgonite, ejaculatory sclerite ST6 and hypandrium as in Fig. 221; ST1–5 with broad sclerites (Fig. 264). Female. Similar to male except frons 0.234 (0.20–0.26/5) of head width at narrowest. T6 of RV shape; T7 continuous, rear edge recessed midway; T8 as separate sclerites (Fig. 308); ST6–8 and hypoproct as in Fig. 352; spermathecae filiform (Fig. 393); ST1–5 as in Fig. 437. Type material. HOLOTYPE ♂ ♦ *(TLW437) (Bolivia, Chapare; CNC; Fig. 473), labeled: BOLIVIA Cbba Chapare / Villa Turnarí-Cochabamba / road - km 362 - 1550m / Pruett & Wood 24 III.95; HOLOTYPE / Mesembrinella / bullata / T.L. Whitworth. ALLOTYPE ♀ ♦ * (TLW438): same data as holotype except km 365, 3–10.xii.1996, G. & M. Wood (CNC). PARATYPES: Bolivia, Cochabamba. 2 ♀♀, Chapare, Villa Turnarf-Cochabamba road, km 362, 1550 m, 24.iii.1995, Pruett & Wood (CNC). La Paz. 1 ♂*, 1 ♀ *, 1 ♀, Sud Yungas, Punte Villa, hotel Tamampaya, 4300 ft., 19–24.v.1989, flight intercept trap, J. Eger (FSCA). Distribution. Bolivia. Remarks. The allotype (TLW 438) was barcoded and was recovered in a distinct cluster near M. uniseta and M. lara (Fig. 488). The terminalia of this species resemble Bonatto’s (2001: fig. 103) sketch of what he called “ xanthorrhina ”. In both specimens the base of the cercus is much enlarged, though in Bonatto’s sketch the cercus is sinuous, whereas in M. bullata sp. nov. it is gently curved forward (Fig. 67). The setae on the disc of T 5 in M. bullata could be confused with the stout setae on the disc seen in the M. aeneiventris species-group. However, the setae in M. bullata are weaker and denser and not in a prominent row. Though the new species groups near two species in the M. aeneiventris group, its surstylus is distinctly curved backward. For now, we place it in the M. bicolor group pending a more in-depth genetic analysis. Etymology. The species name bullata, derived from the Latin bullatus (inflated), refers to the unusual bulbous basal half of the cerci when seen in posterior view (Fig. 68).Published as part of Whitworth, Terry L. & Yusseff-Vanegas, Sohath, 2019, A revision of the genera and species of the Neotropical family Mesembrinellidae (Diptera: Oestroidea), pp. 1-146 in Zootaxa 4659 (1) on pages 120-121, DOI: 10.11646/zootaxa.4659.1.1, http://zenodo.org/record/337723