Drosophila (Drosophila) peixotoi, Vaz & Vilela & Carvalho, 2018

Vaz, Suzana Casaccia, Vilela, Carlos Ribeiro & Carvalho, Antonio Bernardo, 2018, Two new species of Drosophila (Diptera, Drosophilidae) associated with inflorescences of Goeppertia monophylla (Marantaceae) in the city of São Paulo, state of São Paulo, Brazil, Revista Brasileira de Entomologia 62 (2), pp. 159-168 : 163-166

Drosophila (Drosophila) peixotoi sp. nov. ( Figs. 34–56).

Drosophila sp. G 4, Vaz et al., 2014:608 ( Table 1 , feeding site), 610 (Table 2, feeding site), 611 (Table 3, breeding site), suppl. key S1 (feeding site, key), suppl. key S2 (breeding site, key).

Diagnosis. Small-sized dull brown fly, with a relatively large head in lateral view, body length (excluding wing) about 2.1 mm (male) and 2.2 mm (female), front brown, ocellar triangle dark brown; scutum pollinose, light brown anteriorly and between dorsocentrals, gradually darkening toward lateral and distal regions; scutellum dull dark brown; setae and setulae dark brown with a remarkable golden sheen; wings light brown hyaline, tips of veins R 2+3, R 4+5 and M slightly clouded, crossveins slightly clouded (dM-Cu darker), lappet bearing one thick and one thin seta at tip; abdominal tergites shiny; male terminalia conspicuously bearing a large black spine at inner lower tip of cercus; oviscapt valve distally short and blunt, submarine-shaped.

Material examined ( 10 males, 10 females, deposited in MZSP). Holotype male (wild-caught, coded M18, double-mounted, right wing removed, dissected [ Figs. 41–53]) labeled: “ Brasil – SP – São Paulo, Reserva Florestal do [Forest Reserve of] IB-USP, Cidade Universitária , 26.XII.2006, Vilela coll. / Drosophila peixotoi [male symbol] Vaz, Vilela & Carvalho/fotomicrografado [photomicrographed]/terminália ilustrada [illustrated terminalia]/HOLOTYPE/[glass microvial with terminalia and right wing in glycerin]” . Paratypes ( 9 ♂♂ [one with right wing removed ( Fig.40)], 10 ♀♀ [one photomicrographed ( Figs.37-39) and dissected ( Figs. 54–56)]), same data as holotype .

Type locality. Forest Reserve of the Instituto de Biociências da Universidade de São Paulo (IB-USP) (23 ◦ 33.96 Ɩ S; 46 ◦ 43.72 Ɩ W), Cidade Universitária “ Armando de Salles Oliveira ”, São Paulo city, state of São Paulo, Brazil.

Description. Male ( n = 10). Head relatively large in lateral view, brown. Frontal length 0.26 (0.24–0.29) mm, frontal index = 0.98 (0.83–1.00), top to bottom width ratio = 1.33 (1.17–1.50). Frontal triangle laterally shiny, 60–80% of frontal length; ocellar triangle shiny dark brown, 40–50% of frontal length. Orbital plates shiny, 75–91% of frontal length. Orbital setae black, or2 outside or1 and or3; distance of or3 to or1 = 75% of or3 to vtm, or1/or3 ratio = 0.85, or2/or1 ratio = 0.38, postocellar setae = 52 (50–73)%, ocellar setae = 78 (67–91)% of frontal length; vt index 0.92 (0.78–1.00); vibrissal index 0.88 (0.83–1.00). Face and cheek light brown. Carina light brown, prominent, narrow, not sulcate. Cheek index 6–10. Eye index = 1.28 (1.18–1.58). Scape and pedicel light brown, first flagellomere brown, length to width ratio = 1.68 (1.50–2.00). Arista with 4–5 dorsal, 2 ventral long branches, and 4–6 inner branches relatively long, plus terminal fork. Proboscis and palpus brown.

Thorax subshining, mostly brown; length 0.87 mm; 6 rows of acrostichals. Transverse distance of dorsocentral setae 213% of longitudinal distance; dc index 0.64. Scutellum pollinose dark brown, apically blunt; distance between apical scutellar setae 100–150% of that between apical and basal one; scut index = 0.94 (0.80–1.07); basal setae divergent, apical ones cruciate. Pleura subshining dark brown, sterno index = 0.48, median katepisternal seta 33–67% of anterior one. Halter light brown. Legs uniformly light brown; apical seta on protibia and mesotibia; preapical seta on all tibiae.

Wing ( Fig. 40) light brown, crossveins R-M and dM-Cu, and apices of veins R 2+3, R 4+5 and M slightly clouded; length 1.82 (1.71–1.95) mm, length to width ratio = 2.10 (2.03–2.19). Indices: C = 2.94 (2.72–3.13), ac = 2.13 (1.88–2.43), hb = 0.30 (0.25–0.38), 4C = 0.82 (0.76–0.89), 4v = 1.67 (1.59–1.83), 5x = 1.48 (1.29–1.67), M = 0.49 (0.43–0.55), prox. X = 0.53 (0.45–0.67).

Abdomen ( Figs. 34–36) shiny brownish, tergite 1 yellow, tergites 2–4 anteromedially yellow with a distal dark brown band, medially interrupted and laterally broadened, reaching anterior margin of tergite; tergite 4 bearing an irregular coffee brown spot on the median region of the yellow area; tergites 5–6 entirely coffee brown (tergite 5 anteriorly lighter submedially in some specimens).

Male Terminalia ( Figs. 41–53). Epandrium ( Figs. 41–43, 52) almost bare, slightly microtrichose on posterior dorsal area; upper setae absent; 4–5 lower setae in a vertical row; ventral lobe not covering surstylus. Cercus microtrichose on dorsocentral area, conspicuously bearing a strong, long (ca. 2/3 length of cercus), slightly curved spine at inner lower tip, linked to epandrium by membranous tissue ( Fig. 43); the curved spine bears a longitudinal line along most of its length that could be an indication that it has originated from the fusion of two spines. Surstylus not microtrichose, with about 8–9 cone-shaped prensisetae, about 10–12 long, strong outer setae and about 9 long, thin, mostly inner setae. Decasternum upper-positioned, as in Fig. 52. Hypandrium ( Figs. 44–46, 53) as long as epandrium, anterior margin convex; posterior hypandrial process absent; dorsal arch W-shaped, strongly sclerotized ( Figs. 46, 53); gonopod not microtrichose, linked to paraphysis by membranous tissue, bearing one long seta on anterior inner margin. Aedeagus ( Figs. 47–51) distally bifid (in dorsal and ventral views, Figs. 47, 51), distal 1/3 laterally covered with many spines, marginally serrated ventrally ( Fig. 50), turned abruptly dorsad ( Fig. 49) and bearing a dorsoventral lappet, mediodorsally with a pair of membranous, anterodorsally slightly sclerotized, finger-shaped, backwards directed, conspicuous processes ( Figs. 48–50), which are strongly expanded laterally as two triangle-shaped structures (in dorsal view, Fig. 47), shorter than aedeagus (ca. 1/3 its length) and lateroventrally covered with tiny spines; dorsal cleft restricted to a tiny opening adjacent to the fusion aedeagus-aedeagal apodeme; paraphysis dorsodistally swollen, not microtrichose, bearing a setula on posterior inner margin just adjacent to swollen area ( Figs. 45, 46, 53). Aedeagal apodeme rod-shaped, as long as aedeagus; anteriorly slightly expanded dorsoventrally ( Figs. 49, 50). Ventral rod triangle-shaped, completely fused to aedeagal apodeme ( Fig. 49).

Female ( n = 10). Color difference from male: in some specimens, color pattern of tergite 5 is similar to that of male tergite 4.

Measurements: Frontal length 0.26 mm; frontal index = 0.87, top to bottom width ratio = 1.25. Frontal triangle 60–80% of frontal length. Ocellar triangle 33–50% of frontal length. Orbital Plates 80–100% of frontal length. Distance of or3 to or1 = 60–100% of or3 to vtm, or1/or3 ratio = 0.88 (0.75–1.12), or2/or 1 ratio = 0.31 (0.22–043), postocellar setae = 69 (64–75)%, ocellar setae = 75 (64–80)% of frontal length; vt index = 0.99 (0.88–1.12); vibrissal index = 0.78 (0.71–0.86). Cheek index 9.75 (9.00–10.50). Eye index = 1.30 (1.20–1.38). First flagellomere length/width ratio = 1.62 (1.25–1.75).

Thorax length 0.93 (0.88–1.00) mm. h index = 0.90 (0.62–1.00). Transverse distance of dorsocentral setae 171–260% of longitudinal distance; dc index = 0.68 (0.56–0.79). Distance between apical scutellar setae 100–125% of that between apical and basal one; scut index = 0.92 (0.87–1.00), sterno index = 0.57 (0.46–0.69), median katepisternal seta 46–69% of anterior one. Wing length 1.98 (1.82–2.10) mm, length to width ratio = 2.16 (2.08–2.22). Indices: C = 3.19 (2.89–3.44), ac = 2.00 (1.78–2.43), hb = 0.29 (0.24–0.32), 4C = 0.77 (0.71–0.82), 4v = 1.67 (1.50–1.84), 5x = 1.49 (1.22–1.83), M = 0.49 (0.42–0.55), prox. x = 0.52 (0.46–0.59).

Female terminalia ( Figs. 54–56). Valve of oviscapt distally relatively short, submarine-shaped in lateral view, double-walled, inner wall ( Fig.56, dotted line) ca.2/3 narrower than outer wall, apically roundish, submedially slightly expanded dorsad looking like a submarine sail, ventrally strongly convex, with ca. 14 discal and about 11 marginal, peg-like, mostly roundish-tipped, outer ovisensilla; trichoid-like inner ovisensilla: 3 thin distally positioned, and 1 long, slightly curved, subterminal. Spermathecal inner capsule light bulb-shaped, sclerotized, not furrowed at base; basal introvert deeply invaginated.

Ecology. Breeds on inflorescences of Goeppertia monophylla ( Table 1 ).

Etymology. Named after Dr. Alexandre Afrânio Peixoto (1963–2013) for his research contributions on Drosophila genetics, evolution, and behavior (Laboratório de Biologia Molecular de Insetos, Fiocruz, Rio de Janeiro, Brazil).

Note. Five isofemale lines of Drosophila peixotoi sp. nov. were established by Flavia J. Krsticevic from flies aspirated from inflorescences of Goeppertia cylindrica of a private backyard garden in Santa Teresa district, Rio de Janeiro. The five isofemale lines (coded STA-KF7, STA-KF8, STA-KF9, STA-KF11, STA-KF12) were reared for several generations on a G. cylindrica enriched medium described in Vaz et al. (2014), and samples are preserved in ethanol in the laboratory of one of us (ABC). However, it should be pointed out that no adults of Drosophila peixotoi sp. nov. emerged from G. cylindrica inflorescences collected in the Jardim Botânico district (22 ◦ 57.95 Ɩ S, 43 ◦ 14.31 Ɩ W), adjacent to Parque Nacional da Tijuca ( Rio de Janeiro city), although they were frequently found feeding on these inflorescences in nature ( Vaz et al., 2014:610, 611 [Tables 3, 4]).