Mesembrinella bicolor ( Fabricius, 1805 )

Whitworth, Terry L. & Yusseff-Vanegas, Sohath, 2019, A revision of the genera and species of the Neotropical family Mesembrinellidae (Diptera: Oestroidea), Zootaxa 4659 (1), pp. 1-146 : 117-119

Mesembrinella bicolor ( Fabricius, 1805)

( Figs 7 13, 63–64, 153–154, 194, 219, 262, 306, 350, 391, 435, 488)

Musca bicolor Fabricius, 1805: 291 . Holotype female (NHMD), not examined. Type locality: “America Meridionalis” [= South America].

Mesembrinella bicolor: Peris & Mariluis (1984: 261) ; Toma & Carvalho (1995: 137); Marinho et al. (2012: 142); Kosmann et al. (2013: 78); Wolff (2013: 121); Wolff & Kosmann (2016: 868); Marinho et al. (2017: tab. 1); Velásquez et al. (2017: 109); Cerretti et al. (2017: tab. 2).

Diagnosis. Size variable: averaging 11 mm (8–13/5) in length, most specimens seen between 12 and 13 mm in length. Thorax reddish-brown with faint pale tomentose stripes; abdomen gleaming blue [in well-preserved specimens; shiny brown in poor specimens]. Postpronotal setae 3x 3; stem vein bare; wing hyaline, but area from costa to R 1 and areas along veins usually moderately yellowed under magnification and reflected light; subcostal sclerite bare; section IV of wing 0.28 of section III; discs of upper and lower calypters tan; upper calypter with tan rim and short brown setae, lower calypter with pale rim and long pale setae. Epandrium, cerci and surstyli as in Figs 63–64. Female terminalia as in Fig. 306. [A common and widespread nondescript species that occurs over a wide area of the Neotropical Region and which tends to be somewhat variable.]

Redescription. Male. Head. Frons 0.027 (0.015 –0.050 /5) of head width at narrowest [this species is widely distributed, and frons width can be variable]. Fronto-orbital and parafacial with silvery tomentum when viewed from above, orange tomentum when viewed from below; frontal setae ascending about halfway to vertex; frontal vitta orange, obliterated from midway up; gena and postgena orange with silvery tomentum, with mostly long golden setae, gena with horizontal row of three stout setae; occiput with silvery tomentum and yellow setae; median occipital sclerite broad, shiny dark orange ( Fig. 13); antenna orange, arista reddish-brown; palpus typical; eye with median facets about 3x size of lateral facets; ocellar triangle medium-sized, ocelli about equal-sized; supravibrissal setae dark brown, ascending about 1/6 of distance to antennal base.

Thorax. Dorsum reddish-brown with faint pale whitish tomentose stripes; pleura yellowish; chaetotaxy: ac variable, 2:2 to 2:3, sometimes anterior postsutural ac missing on one or both sides, dc 2:3, ia 1, ph, 1; ppn 3x 3, kat 2:1, meral setae a vertical line, usually with only 1 horizontal seta, 1 pair converging ap, sa absent, 1 very weak lat, 1 stout bas, 1 very weak pb, 1 disc ( Fig. 194); subscutellum weakly developed; spiracles medium-sized, yellow-orange; legs: trochanters and femora orange, tibiae and tarsi more or less brownish. Wing appearing hyaline, but area from costa to R 1 and areas along veins distinctly yellowed when observed under reflected light; subcostal sclerite bare; basicosta and tegula orange; section IV 0.28 of section III; discs of calypters light tan; rim of upper calypter brown with short brown setae, rim of lower calypter pale with long pale setae.

Abdomen. T1+2 more or less yellowish midway, metallic blue laterally, T3–5 metallic blue with whitish tomentum, T4–5 with marginal setae; disc of T5 with dense, medium-long, fine setae only. Terminalia in lateral view with surstylus moderately curved backward ( Fig. 63); in posterior view, base of cerci broad, evenly tapered to tips ( Fig. 64); phallus in lateral view with epiphallus with moderate backward curve ( Fig. 153); in dorsal view, hypophallic lobes expanded slightly, edges of lobes with coarse, shallow serrations ( Fig. 154). T6, STS7+8, pre- and postgonite, ejaculatory sclerite, ST6 and hypandrium as in Fig. 219; ST1–5 as in Fig. 262.

Female. Similar to male except frons 0.278 (0.25–0.31/5) of head width at narrowest and eye with median facets about 2x size of lateral facets. T6 of OV shape; T7 slender, divided midway; T8 as separate sclerites ( Fig. 306); ST6–8 and hypoproct as in Fig. 350; spermathecae filiform ( Fig. 391); ST1–5 as in Fig. 435.

Material examined. Bolivia, Santa Cruz. 1 ♀, 210 km NW of Santa Cruz at Rio Yapacani , 5–10.v.1983, insect flight trap, D.G. Young ( FSCA) . Brazil, Rondônia. 1 ³♦ ( TLW428 ) , 2 ³³, 3 ♀♀, 62 km SW Ariquemes. Nr. Fzda. Rancho Grande , 6–15.xii.1990, D.A. Rider, J.E. Eger ( FSCA) ; 3 ♀♀, same data except 4–16.xi.1997, Fish carrion pitfall ( FSCA) ; 1 ♀, Maracaju , ii.1937, M. Grosso ( USNM) ; 3 ♀♀, same data except v. vi.1937, R.C. Shannon; 1 ³♦* ( TLW457 ) , vic. Caucalandia , 10°32ʹS 62°48ʹW, 160–350 m, 10–11.x.1991, J. MacDonald ( MEM) ; 1 ♀, same data except 12–13.X.1991 ( MEM) ; 1 ³♦ ( TLW457 ) , same data except 14.x.1991 ( MEM) . Costa Rica, Alajuela. 1 ³*, Upala Bijagua, Albergue Heliconias , 700 m, 22–29.vi.2000, L_N_298000 423800 #56844, J.D. Gutierrez de Luz ( INBIO) ; 1 ³, P.N. Volcau Teurio Est. Pilon, 1.5 SO C. Carmela , 700–800 m, 5.vii–17.viii.2006, Malaise trap, L_N_298212 427913 #86941, J.A. Azofeifa ( INBIO) ; 1 ♀, Bijagua, P.N. Volcan Teurio, Albergue Heliconias, Send. Heliconias , 680 m, 1.ii.2008, Tp. Luz, L _N_299100 422600 #94184, A. Zumbado ( INBIO) . Guanacaste. 1 ³, Est Las Pailas , 800 m, P.N. Rincón de la Vieja, 27.vii–15.viii.1992, L_N_306300 388600, C. Cano ( INBIO) ; 1 ³, Sendero, Pailas, Catarata , 800 m, 11–12.i.1994, L_N_306300 388600 #2666, M. Zumbado ( INBIO) ; 1 ³, Estación Santa Rosa, 300 m, 5.iv.1997, L_N_313000 359800 #50732, D.H. Janzen, Gusaneros ( INBIO) ; 1 ³♦ ( TLW357 ) , Santa Cruz, vista del mar Torre Cocfsna 972 m, 10.ii.2003, Libre, L _N_235350 357500 #73267, W. Porras ( INBIO) ; 3 ♀♀, Santa Rosa, 16–17.i.2005, [no collector] ( INBIO) . Heredia. 1 ³♦ ( TLW351 ) , 1 ♀, Santo Domingo , 10.i.2011, bait trap, T.L. Whitworth ( TW) . Limón. 1 ³, Est. Hitoy Cerere , 100 m, R. Cerere Res. Biol. Hitoy, 13–27.iv.1992, L_N_184200 643300, G. Carballo ( INBIO) ; 1 ♀, same data except ix.1991 ( INBIO) ; 1 ³, 2 ♀♀, Hdas. La Suerte / Tapezco, 29 air km W Tortuguero , elev. 40 m, 10°27ʹ–30ʹN 83°47ʹW, 13–31.viii.1979, J.P. & K.E. Donahue, C.C. Hair, N.K. Moore, M.A. Hopkins ( LACM) ; 1 ³, R.B. Hitoy Cerere, Valle de la Estrella, Send. Espavel , 560 m, 27–30.ix.2003, L_S_401200 569800 #75563, Libre, W. Arana ( INBIO) ; 1 ³, Amburi , 70 m, ix.1996, L_S_385000 578100 #8397, G. Gallardo ( INBIO) ; 1 ♀, same data except Talamanca , 6–11.vi.1993, L_S_ 385500 578050 ( INBIO) ; 1 ³, Guacime , LRO 15 km NE, 23.ii.1988, F.D. Parker, J.B. Welch, F. Ramírez ( USNM) .

Puntarenas. 1 ³, Est. Sirena , 0–100 m, P.N. Corcovado, iv.1992, L_S_ 270500 508300, G. Rodríguez ( INBIO) ; 1 ♀, same data except x.1989, G. Fonseca ; 1 ♀, same data except vi.1990, F. Quesada ( INBIO) ; 1 ³, Tropical youth center, 5 km S of Rincón, 95 m, 8°42.1ʹN, 83°30.8ʹW, 11.viii.2001, at light, N.E. Woodley ( USNM) ; 1 ³*, 3 ♀♀ ♦ ( TLW354 – TLW356 ) , Mauglar boca Rio Arajuez, Pto A, 2 km SW Cocal, 20 m, 16.xii.2006, Tp. Frutas, L_N_ 219755 44651 #90195, Moraga, Zumbado, Azofeifa, Gamboa ( INBIO) ; 1 ³, Est. Sirena, P.N. Corcovado , 0–100 m, vi.1990, L_S_ 270500 508300, F. Quesada ( INBIO) ; 1 ♀, Cobano, R.N.A. Cabo Blanco, Estac. Cabuya, Send. sueco 200–300 m, 13.iii.2002, Libre, L _N_173500 415500 #67200, Y. Tardenas ( INBIO) ; 1 ♀, San Vito de Java , 26.iv.1954, J.O. Harrison ( FSCA) . San José. 1 ♀, Z.P. Mora El Rodeo, Fila Diamaute , 900–1000 m, 3.xii.2005, Tp. Frutas, L_N_209300 507000 #95137, A. Hoepker, J. Mata ( INBIO) . Ecuador, Imbabura. 4 ³³, 6 ♀♀, Lita Imbabura , 12.iv.2016, traps 1–5, 2016-10, P. Ponce ( FSCA) . El Salvador, Santa Tecla. 2 ♀♀, 900 m, 26.v.1972, S. Leg & L. Steinhauser ( FSCA) . French Guiana. 1 ³*, 10 ³³, 1 ♀ *, 6 ♀♀ ♦ ( TLW242 – TLW247 ) , 4 ♀♀, Kaw Mountain , 04°33ʹ58ʺN 52°12ʹ43ʺW, 310 m, 4–9.ii.2008, bait trap T.L. Whitworth ( TW) . Guatemala, San Marcos. 2 ♀♀, Bojoual 1600 m, 2.vii.2011, F. Camposeco ( WSU) . Suchitepequez. 1 ³*, 1 ♀ *, Univ. Guatemala Res. Sta- tion, 1500 m, 14°32ʹ88ʺN 91°11ʹ62ʺW, 10.vi.2011, F. Carillo ( TW) . Honduras, Tegucigalpa. 1 ³, Escuela Agricola Panamericana , 28.xi.1983, swine feces, J. Dick ( FSCA) . Mexico, Tamaulipas. 2 ♀♀, Gomez Farias, Atlas Ci- mas, 1000 m, 20.iii–29.iv.1987, carrion pitfall trap, Kovarik ( TAMU) ; 1 ♀, Tamaulipas, Santa Engracia , 20.x.1937 ( TAMU) . Panama, Cocle. 2 ³³♦ ( TLW426–427 ) , El Valle de Anton, Sen. Los Arboles Cuadrato , FIT 8.61669°N, 80.13336°W, 6–7.viii.2011, E.G. Riley ( TAMU) ; 2 ³³, same data except 6–7.viii.2011 ( TAMU) ; 1 ♀, Almirante Bocas del Toro , yellow camp fever, Shannon trap, [no collector] ( FSCA) ; 1 ♀, same data except 15.viii.1951 .

Canal Zone. 1 ♀, Black Tank Rd. Ft. Sherman, 1.i.1985, J. & S. MacDonald ( MEM) ; 1 ♀, Gatun, West Creek Trail , 7–9.iv.1987, J.R. MacDonald ( MEM) ; 1 ♀, Caurto , Shannon trap, 11.v.1961, [no collector] ( FSCA) ; 1 ³, Cristobal v.1960, Malaise trap, S.G. Breeland ( FSCA) ; 1 ³*, Pan Barro Colorado , 8.viii.1978, R.B & L.S. Kimsey ( UCDC) ; 1 ³♦ ( TLW446 ) , Cerro Paraiso , 4.i.1986, J. & S. MacDonald ( MEM) ; 1 ♀ ♦ ( TLW447 ) , Black Tank Rd, Ft Sherman , 1.i.1986, J. & S. MacDonald ( MEM) . Peru, Cusco . 1 ♀, Madre de Dios Parque Manu, Pakitza 11°53ʹS 70°58ʹW, 400 m, 16.xi.1990, J. MacDonald ( MEM) . Suriname, Brokopondo. 1 ♀, nr. Brownsberg , Ston Eliand Eco Ressort, N 04°59.0ʹ, W055°08.0ʹ, 10–13.ii.2010, Banana trap, P. Skelley ( FSCA) . Trinidad and Tobago, 1 ³, Trinidad, 8 km N Arima, Simla Res. Sta. 260 m, 14.vi.93, trop. Forest, FIT & S. and J. Peck ( CNC) ; 1 ³, St Augus- tine, Pax Guest House , 29.x–3.xi.2000, black light trap, R.E. Woodruff ( FSCA) ; * 1 ♀, Arima Valley “simla” Beebe Trop. Res. Center , 29.x–2.xi.2000, dung traps, R.I. Hernández and R.E. Woodruff ( FSCA) ; 1 ♀, same data except 3–17.xi.2000, hand catch at night. Venezuela, Bolivar. 1 ³, Carret. Caicara, San Juan de Manapiare , km 170, 300 m, 21–30.xii.1973, J.L. Garcia ( MIZA) ; 1 ³♦ ( TLW425 ) , Edo. Lara, PN Yacambu-El blanquito 11–16.iii.2002, [no collector] ( MJMO) .

Distribution. Bolivia, Brazil, Costa Rica, Ecuador, El Salvador, French Guiana, Guatemala, Honduras, Mexico, Panama, Peru, Suriname, Trinidad, Venezuela. Marinho et al. (2017) stated this species occurs in Central, South America except Chile, Argentina.

Remarks. Thirty-two specimens were barcoded: TLW 428 and TLW 457 from Brazil, TLW 193, TLW 351 and TLW 354–357 from Costa Rica, TLW 226, TLW 248–250 and TLW 441–442 from Ecuador, TLW 242–247 from French Guiana, TLW 347–348 and TLW 426–427 from Panama, TLW 222–225 and TLW 443 from Peru, TLW 350 from Suriname, and TLW 349 and TLW 372 from Trinidad ( Fig. 488). This species is widespread in the Neotropical Region and the barcodes grouped into several clusters in the NJ analysis. Typically, barcodes for specimens collected in close proximity were very similar. For specimens from widely separated geographical areas, as is the case of M. bicolor , the NJ analysis showed considerable molecular divergence, though morphologically the specimens were very similar. A similar situation was discussed by Tantawi et al. (2017) and Yusseff-Vanegas & Agnarsson (2017), who mentioned that barcode data for common, widespread species like Lucilia eximia ( Wiedemann, 1819) suggested the existence of several cryptic species. Whitworth (2014) studied the morphology of L. eximia from many different areas, and although there were slight morphological differences between populations, he could not identify reliable characters to justify splitting them into separate species. It is likely that a similar situation exists with M. bicolor . A specimen from Brazil keyed to the bicolor species-group because it had 2x 2 postpronotal setae, but it would not key to a known species. The specimen was barcoded ( TLW 457) and it grouped with M. bicolor . Once it was assumed that this specimen’s condition was aberrant and that its normal condition was to have 3x 3 postpronotal setae, it keyed perfectly to M. bicolor .

Without microscopic examination, the wing of M. bicolor appears hyaline; under a microscope, and using reflected light through the wing, the area along the costa is distinctly yellowish. To key specimens properly, this condition must be recognized. Variation was noted in frons widths in both sexes and some series of smaller specimens were also seen. A detailed study of morphology supports retaining a single, somewhat variable, species, but further studies are warranted.