Stenomicra urbana, Gomes & Ale-Rocha & Keppler, 2018

Gomes, Eliane Solar, Ale-Rocha, Rosaly & Keppler, Ruth Leila Ferreira, 2018, A new species of Stenomicra Coquillett (Diptera: Periscelididae) from the Brazilian Amazon and its life history, Zootaxa 4407 (4), pp. 591-599 : 593-596

Stenomicra urbana sp. nov.

( Figs 2 –21)

Adult. Diagnosis. This species can be differentiated from congeners by the following set of features: Thorax and abdomen yellow except for dorsal, wide, median, brown stripe, extended from anterior margin to middle of scutum, scutellum with brownish apex, and a small brown spot on anepimerum of males and anepimerum and katepisternum of females, third and fourth tergites of males, plus posterior margin of second tergite of females; two dorsocentral postsutural setae developed, posterior stronger and longer, twice as long as anterior; wing hyaline, section R4+5-M1 a little shorter than section R2+3-R4+5; legs yellow with coxae, trochanters, base of femora, mid tibia and mid tarsus pale-yellow; fore femur with two long and strong setae on posteroventral surface near apex.

Description: Holotype male. Head rather wider than high in frontal view; eyes almost parallel on frons, with a distinct indentation just below the insertion of antennae and distinctly approximated at middle of face; facets undifferentiated, densely setulose ( Fig. 2 ). Frons yellow, shiny, with black ocellar triangle close to vertex. Face yellow with lateral margin smoothly brown, more than twice length of frons in frontal view, slightly concave on upper half and with sharp protuberance in the middle; facial setae developed, upper pair (pseudovibrissae) stronger, lateroclinate and brown, inserted on protuberance of face, 9 lower pairs of yellow bristles, curved inward, distributed on gena to post-gena; gena yellow with narrow band of silver pruinescence bordering eye ventrally; postgena pale-yellow with sparse fine pale-yellow pruinescence. Antenna yellow, slightly orange; scape very short; pedicel with short brown setae, and one more developed dorsoapical seta; postpedicel almost rectangular, a little longer than wide with distal margin rounded, with conspicuous dorsoapical yellow setae; arista sub-basal dorsal, brown, with six dorsal and three ventral branches, becoming shorter towards apex, with short intercalated branches. Clypeus yellow. Buccal pieces yellow with yellow setae. Postcranium yellow. Setae pale-brown: one pair of outer vertical setae long, erect, slightly reclinate; one pair of short inner vertical setae, about ½ length of outer pair, slender, strongly proclinate, almost horizontal; two pairs of reclinate fronto-orbital setae, posterior pair robust and three times longer than thin anterior pair, and as long as the outer vertical pair. Thorax ( Figs 3, 4 ): Scutum yellow, softly yellow-orange tinged on dorsum, with wide, longitudinal brown stripe between dorsocentral series, extended form anterior margin to middle of scutum. Postpronotal lobe and notopleuron paler. Scutellum yellow with brownish apex and basal corners; subscutellum brownish. Pleuron yellow, except for a small brown spot on anterior margin of anespiternum and on anepimeron. Sternum yellow. Thoracic setae pale-brown to yellow; dorsocentral and acrostichal series uniserial; 1 small, fine postpronotal; anepisternum and katepisternum with fine small yellow setae. Long and strong setae: 2 notopleural, 1 supralar presutural; 2 dorsocentral postsutural, posterior seta stronger and twice longer than anterior seta; 1 katepisternal; 1 scutelar subapical. Pruinescence fine, paleyellow. Wing ( Fig. 3 ): hyaline; rather slender and long (W/L 0.39); cross veins r-m and m-cu rather close together (L r-m / L between r-m and m-cu 0.45); length of section R2+3-R4+5 about 1.4 times longer than section R4+5-M1. CuA1 incomplete; vein A1+CuA2 absent; alula small and anal lobe undeveloped. Legs ( Fig. 3 ): yellow, coxae, trochanters, base of femora, mid tibia and mid tarsus pale-yellow; fore femur with 2 long and strong setae on posteroventral surface near apex and hind femur with some elongate thin setae on posteroventral surface. Apical spine of midtibia developed, pale-brown. Abdomen ( Figs 3, 4 ): yellow, except for third and fourth tergites, brown; setae short, pale brown and sparse; T1+2 long, longer than T3 or T4, T7 longer than tergites T5 and T6 together. Terminalia ( Figs 5–7 ): epandrium deep with strong setae; cercus largely membranous, bearing two elongate and slender setulose lobes, each lobe bearing 1 long and robust seta on apex. Surstylus rather long and robust, slightly curved inward with sharpened apex, bearing thin short setae near base and apically. Hypandrium nearly symmetrical, slender anteriorly, continuous around base of phallus, posteriorly open with asymmetrical appendages (pregonites) projecting posteroventrallly and bearing thin setae laterally. Phallus swollen, largely membranous; phallapodeme sclerotized, distinct; ejaculatory apodeme as illustrated; postgonites lacking.

Female: as in the male except for postpedicel with dorsal stain brown, anepimeron and katepisternum with a large brownish stain, and distal margin of second tergite brownish. Terminalia (Figs 8, 9): syntergosternite T7+S6+S7 longer ventrally than dorsally; sternite 8 reduced to a narrow weakly sclerotized strap; hypoproct rather rectangular; cerci short. Two spherical spermathecae hardly pigmented (Fig. 10).

Type material: Holotype male ( INPA): BRASIL, Amazonas, Manaus / INPA-Campus II / 20–24. iv.2017 / Armadilha Suspensa com septo amarelo / Gomes, E.S. & Ferreira-Keppler, R.L . Paratypes: same data of holotype, 17♂, 6 ♀ ( INPA) . Condition of holotype: good, not dissected.

Additional material: BRASIL, Amazonas, Manaus, INPA/Campus II, Araceae , Alocasia macrorrhiza , 18.iii.2014 (1 ♂); 19.iii.2014 (1 ♂); 29.iii.2014 (1 ♀); 09.iv.2014 (1 ♀); 24.iv.2014 (1 ♀); 13.v.2014 (1 ♂), 24.v.2014 (1 ♂); 25.v.2014 (1 ♂); 17.vi.2014 (1 ♀); 25/vi/2014 (1 ♀); 27.vi.2014 (1 ♂).

Etymology. From the Latin urbanus (“of the city”), in reference to the collection site.

Remarks. Two species were previously known from the Amazon, Stenomicra amazonensis and Stenomicra manausensis ( Freitas & Ale-Rocha 2011) . Stenomicra urbana sp. nov. can be easily distinguished from those species by the yellow scutum with wide brown stripe on anterior half, acrostichal series uniserial, all legs yellow, wing hyaline and tergites yellow except T3 and T4 brown. In S. amazonensis the scutum is brown, the mid femur is brown on anterodorsal surface, the hind femur is brown with yellow tip and base and the basal halves of mid and hind tibiae are brown, the wing is smoothly darkened and the tergites are brown except for T1 and T4, which are yellow. In S. manausensis the scutum is yellow with posterior margin brown and the acrostichal series is biserial. The male terminalia offers the most important characters to distinguish Stenomicra urbana sp. nov. from those Amazonian species: the lobe of the cercus is elongate and slender (the lobe is short and robust in S. amazonensis and reduced, almost imperceptible, in S. manausensis ) and the surstylus is sharpened apically with thin and sparse setae on the apex (the surstylus is robust and totally covered with short and strong setae in S. amazonensis , with long and strong setae and apex slightly enlarged in S. manausensis ).

Third instar larva ( Figs 11–17 ). Description. Length 5.0– 5.6 mm (n=3). Body fusiform, inconspicuously dorsoventrally flattened; integument soft, whitish to semi-transparent; cephalic segment truncated anteriorly and posterior end terminating in two short pointed process ( Figs 11–14 ). Opening of prothoracic spiracle on discrete, short, digitiform process, with spiracle ending in 7 thin branches ( Fig. 15 ). Antennomaxillary lobes indistinct. Thorax and abdominal segments with fine and short dorsal and lateral whitish setae. Locomotory welts evident on anterior margin of abdominal segments, with transverse rows of spines, one irregular row on border of crest with small spines and two central rows formed by very short spines and larger flattened spines with curved tip ( Fig. 16 ). Anal pads small and inconspicuous, but a pair of small, inflated lobes could be everted during the preparation process of the larva for electron microscopy; a row of 6 short curved spines arranged in semicircle behind anal pads ( Fig. 17 ). Posterior spiracles located on bifurcated spiracular process, with long and thin branches, arising distally on abdominal terminal segment; base of bifurcated process enlarged, like a collar ( Figs 14, 17 ). Telescoping cephalopharyngeal skeleton ( Figs 18, 19 ) slender, rather asymmetrical; basal sclerite black and heavily sclerotized, except for the less sclerotized distal portions of the dorsal and ventral cornua; ventral cornu narrow in lateral view and slightly longer than dorsal cornu, very slightly sclerotized; parastomal bar short and robust; mouthooks separate, robust and strongly curved inward; intermediate sclerite slender.

Puparium (Figs 20, 21). Description. Average length 4.09 mm (n=11). Yellow-orange and conceal the exuvium of the final larval instar. Body slightly robust and wider in the middle, elliptical in profile, slightly tapering towards anterior end and truncated at apex; first thoracic segment with a small digitiform process (vestige of anterior spiracle); eight abdominal segments, each with two rows of micro thorns; last abdominal segment with small transverse anal slit and with bifid pointed process posteriorly. Pupa approximately half length of puparium.

Material. Third instar larva: BRASIL, Amazonas, Manaus, Instituto Nacional de Pesquisas do Amazonas/ INPA, Campus II, 24/II/2014; 08.viii.2014; 25/IV/2014; 20/v/2014; 10/vi/2016 (8 larvae, all deposited in INPA). Puparium: BRASIL, Amazonas, Manaus, INPA/Campus II, Araceae , Alocasia macrorrhiza , 18.iii.2014; 19.iii.2014); 29.iii.2014; 09.iv.2014; 24.iv.2014; 13.v.2014; 24.v.2014; 25.v.2014; 17.vi.2014; 25/vi/2014; 27.vi.2014 (6 puparia, all deposited in INPA).

Figures

FIGURES1–4.Alocasia macrorrhizos (L.) G.Don (Araceae)at anurban forest fragmentat Campus II of InstitutoNacional de Pesquisas da Amazônia/INPA,Manaus, Brazil; 2–4, Stenomicra urbana sp. nov.: 2, head, anterior view; 3, Stenomicra urbana sp. nov., habitus, lateral view; 4, Stenomicra urbana sp. nov., habitus, dorsal view.

FIGURES 5–7. Male terminalia (paratype): 5, epandrium, cerci and surstyli, posterodorsal view; 6, epandrium, cerci and surstyli and internal terminalia, lateral view; 7, hypandrium, phallus and aedeagal apodeme, ventral view. 8–10 female terminalia: 8, dorsal view; 9, ventral view; 10, spermatheca. Scale bar: Figs 5–9 = 0.3 mm; Fig 10 = 0.1 mm. Abbreviations: cerc—cercus; eja apod—ejaculatory apodeme; epand—epandrium;pregt—pregonite; ph—phallus; sur—surstylus.

FIGURES 11–17. Third instar lava of Stenomicra urbana sp. nov.: 11, habitus, lateral view; 12, habitus, dorsal view; 13, head and prothorax, dorsal view; 14,, anterior spiracle; 15, abdominal terminal segment, bifurcated spiracular process, dorsal view; 16, SEM of locomotory welts, ventral view; 17, SEM of abdominal terminal segment, bifurcated spiracular process and anal pads, ventral view.SEM= scanning electron micrographs.

FIGURES 18–19. Cephalopharyngeal skeleton of Stenomicra urbana sp. nov.: 18, dorsal view; 19, lateral view. 20–21, puparium of Stenomicra urbana sp. nov.: 20, dorsal view; 21, ventral view.Scale bar:Figs18–19 = 0.1 mm.