Drosophila (Phloridosa) monsterae, Vilela & Prieto, 2018

Vilela, Carlos R. & Prieto, Danyi, 2018, A new Costa Rican species of Drosophila visiting inflorescences of the hemi-epiphytic climber Monstera lentii (Araceae), Revista Brasileira de Entomologia 62 (3), pp. 225-231 : 228-230

Drosophila (Phloridosa) monsterae sp. nov.

( Figs. 6–29)

Drosophila, subgenus Phloridosa, Prieto and Cascante-Marín, 2017: 61 .

Drosophilid fly, Prieto and Cascante-Marín, 2017: 57, 60 ( Fig. 3b), 61, 63.

Diagnosis. Shining black fly; branches of arista and most setae noticeably short, somewhat erect, black; small slightly circular compound eye; conspicuous broad gena; wing relatively long, hyaline; basal scutellars parallel or slightly convergent; gonopod not microtrichose; aedeagus sinuate in lateral view; inner spermathecal capsule with an unusual folded duct on basal half of introvert.

Material examined. Holotype male (dissected, Fig. 6), labeled: “ Costa Rica, Cartago, La Unión, Cerro de La Carpintera , 9 ◦ 53 l 1 llN, 83 ◦ 58 l 22 llW, altitude 1810 m /collected in closed inflorescence of Monstera lentii ( Araceae ) IX.2010, D. Prieto coll. /# 1 / ♂ Drosophila monsterae Vilela & Prieto /HOLOTYPE [red label]” . Paratypes (10 ♂♂, 13 ♀♀ [2 dissected]); same data as holotype except for the last three labels = specimen number/sex/PARATYPE [red label] .

Description. Male (n = 11; Figs. 6, 7). Head. Frons black, dull, lighter anteriorly, frontal length = 0.33 (0.29–0.37) mm; frontal index = 0.83 (0.76–0.88), top to bottom width ratio = 1.43 (1.17–1.53). Frontal triangle distinct, apically narrow, pointed, about 79–100% of frontal length. Ocellar triangle about 33–46% of frontal length. Orbital plates subshiny, brown, lighter than adjacent frontal areas, apically broadened and slightly diverging from eye margin, about 80–100% of frontal length. Distance of or3 to or1 = 50–67% of or3 to vtm, or1/or3 ratio = 1.16 (1.00–1.25), or2/or1 ratio = 0.34 (0.33–0.40), postocellar setae = 42 (33–54)%, ocellar setae = 44 (38–50)% of frontal length; vt index = 1.29 (1.14–1.60); vibrissal index = 0.28 (0.18–0.50). Occiput black. Length-to-width ratio of flagellomere 1 = 1.55 (1.20–1.75). Arista with 4–6 short dorsal, 2–3 short ventral and 5–10 inner branches, plus small terminal fork. Face light brown. Carina distinctly broadened downwards, dorsally flat, noselike. Eye slightly circular, smaller than usual, index = 1.17 (1.07–1.33). Gena light brown, conspicuously broad. Cheek index = 2.43 (2.00–2.67). Vibrissa relatively long. Proboscis and palpus light brown; clypeus dark brown. Palpus with about two thin median-sized setae along lower margin.

Thorax dark coffee brown, subshiny, length = 1.13 (0.98–1.24) mm. 4–6 rows of acrostichal setulae. Postpronotum not so dark brown. h index = 0.95 (0.83–1.17). Transverse distance of dorsocentral setae 118–150% of longitudinal distance; dc index = 0.61 (0.50–0.69). Scutellum apically roundish, distance between apical scutellar setae about 75–88% of that of the apical to the basal one; basal ones parallel or slightly convergent; distal ones relatively long and not cruciate or cruciate at the very tip; scut index = 0.73 (0.65–0.82). Sterno index = 0.48 (0.38–0.55), mid katepisternal seta about 33–75% of anterior one. Halters light brown. Legs proximally (coxa, trochanter and femur) brown, distally (tibia and tarsi) light brown. Tarsal claw distinctly long.

Wing hyaline, veins yellow, relatively long ( Figs. 6, 7), length = 2.54 (2.34–2.66) mm, length to width ratio = 2.58 (2.45–2.73). First costal section (between humeral and subcostal breaks) with setulae distinctly longer and more erect than those of second section. Indices: C = 3.88 (3.68–4.41), ac = 2.20 (2.00–2.43), hb = 0.22 (0.21–0.26), 4C = 0.67 (0.59–0.73), 4 v = 1.63 (1.50–1.74), 5× = 1.16 (0.90–1.50), M = 0.38 (0.34–0.44), prox. X = 0.63 (0.57–0.70).

Abdomen shining ( Figs. 6, 7), uniformly dark coffee brown except epandrium, cercus and pleura, light brown; length = 1.27 (1.12–1.37) mm.

Terminalia ( Figs. 9–19). Epandrium mostly microtrichose, devoid of setae; ventral lobe ( Fig. 10) distally thumb-shaped, microtrichose, anterodorsally membranous, bearing 2–3 longer setae and 0–1 shorter one. Cerci anteriorly linked to posterior margin of epandrium by membranous tissue, microtrichose ( Figs. 10, 11) except lower 1/4; inner ventral tip double-walled, inner corner somewhat truncated; ventral margin concave in posterior view ( Fig. 11); outer ventral tip projected outwards ( Fig. 11). Surstylus not microtrichose; distal margin bearing a dorsoventral row of ca. 10 long, sharp-tipped, peg-shaped prensisetae, first dorsalmost and two ventralmost longer ( Fig. 9); dorsal half strongly sclerotized, with a transverse, irregular row of ca. 6 outer, long, strong, curved setae; ventral half weak sclerotized, with ca. 5 outer, thinner, shorter setae; ca. 5 inner setae below lowermost prensisetae ( Fig. 10). Decasternum as in Fig. 11. Hypandrium strongly sclerotized ( Figs. 12–14), slightly shorter than epandrium, bearing a pair of sharp lateral projections pointed backwards as seen in the posterior view ( Fig. 14); dorsal arch projected backwards in the lateral view ( Fig. 12); anterior margin concave ( Fig. 14); gonopod perpendicular and mostly fused to paraphysis, devoid of microtrichiae, bearing one long seta on anterior inner margin ( Figs. 12–14). Aedeagus sinuate in lateral view ( Fig. 17), subapically expanded laterally, rounded and slightly incised at tip ( Figs. 15, 19) which is projected upwards; ventral margin subproximally bearing a curved spine projected apicalwards ( Figs. 16–18); dorsal cleft at very anterior end ( Figs. 15–17). Aedeagal apodeme shorter than aedeagus, bent; anterior region dorsoventrally expanded ( Fig. 17). Ventral rod absent ( Fig. 17). Paraphysis perpendicular and mostly fused to gonopod ( Figs. 13, 14), devoid of setulae, linked to distal margin of aedeagal apodeme by membranous tissue.

Female (n = 13; Fig. 8). Difference to male: first costal section (between humeral and subcostal breaks; Fig. 20) with setulae just slightly longer than those of second costal section.

Measurements. Frontal length = 0.33 (0.29–0.37) mm; frontal index = 0.83 (0.75–0.93); top to bottom width ratio = 1.43 (1.28–1.53). Frontal triangle about 79–115% of frontal length. Ocellar triangle about 29–38% of frontal length. Orbital plates about 80–100% of frontal length. Distance of or3 to or1 = 50–83% of or3 to vtm, or1/or3 ratio = 1.07 (1.00–1.20), or2/or1 ratio = 0.38 (0.33–0.40), postocellar setae = 40 (36–46)%, ocellar setae = 45 (36–50)% of frontal length; vt index = 1.28 (1.17–1.40); vibrissal index = 0.27 (0.20–0.38). Length to width ratio of flagellomere 1 = 1.56 (1.40–1.75). Arista with 4–5 upper, 2 ventral and 6–10 inner branches, plus small terminal fork. Eye index = 1.16 (1.06–1.20). Cheek index = 2.55 (2.13–2.83).

Thorax length = 1.12 (0.98–1.24) mm. 4–6 rows of acrostichal setulae. h index = 0.92 (0.67–1.17). Transverse distance of dorsocentral setae 120–200% of longitudinal distance; dc index = 0.59 (0.58–0.64). Distance between apical scutellar setae about 67–100% of that of the apical to the basal one; basal ones parallel or slightly convergent; scut index = 0.71 (0.59–0.81). Sterno index = 0.52 (0.45–0.64), mid katepisternal seta about 29–50% of anterior one.

Wing ( Fig. 20) length = 2.49 (2.20–2.85) mm, length to width ratio = 2.38 (2.29–2.49). Indices: C = 3.74 (3.48–4.12), ac = 2.16 (1.89–2.43), hb = 0.22 (0.16–0.30), 4C = 0.68 (0.61–0.84), 4 v = 1.61 (1.40–1.88), 5x = 1.00 (0.82–1.13), M = 0.36 (0.30–0.40), prox. X = 0.63 (0.57–0.74).

Abdomen length = 1.60 (1.34–1.88) mm.

Terminalia ( Figs. 21–28). Tergite 8 dorsally microtrichose, bearing a curved row of 3–4 setulae adjacent to posterior/ventral margin ( Fig. 22); epiproct and hypoproct microtrichose, setose, bearing a pair of setae longer than adjacent ones ( Figs. 21, 24); valve of oviscapt ( Figs. 24, 26, 29) apically narrowed, subapically expanded dorsad, ventrally convex at proximal half, sinuate at distal half, with ca. 4 discal, trichoid-like, and 10 marginal, peg-like, roundish-tipped (except the anterior most and the posterior most, sharp-tipped) outer ovisensilla; trichoid-like inner ovisensilla: 3 thin, unusually long, distally positioned (middle one probably accidentally missing as seen in Fig. 29), and 1 thick, longer, almost straight, subterminal; valves widely spaced at base ( Figs. 24, 25). Inner capsule of spermatheca ( Figs. 27, 28) finger cap-shaped, apically flattened, strongly sclerotized, devoid of basal furrows and apical introvert; basal introvert deeply invaginated, very wide at base, gradually narrowing toward apex; spermathecal duct unusually folded over itself at lower half of basal introvert.

Differences from consubgeneric species. Drosophila (Phloridosa) monsterae sp. nov. from Costa Rica differs from D. alei , D. alfari , D. cuzcoica , D. denieri , D. lutzii , D. merzi and D. tristani mainly regarding two structures of their heads as follows, respectively. Eye slightly circular vs. slightly elliptical; gena distinctly broad vs. not so broad. They also differ with respect to their terminalia: gonopod not microtrichose vs. distinctly microtrichose (males unknown for D. cuzcoica and D. tristani ); aedeagus without a pair of subapical lateral expansions vs. presence of such structures (males unknown for D. cuzcoica and D. tristani ); oviscapt valve with discal trichoid-like outer ovisensilla vs. discal peg-like outer ovisensilla (females unknown for D. merzi ; unavailable data for D. alfari and D. tristani ) ( Table 1 ).