Robustagramma altifrons Cui and Marshall, 2005

Marshall, Stephen A. & Cui, Yongsheng, 2005, Systematics of Robustagramma, a new genus of New World Sphaeroceridae (Diptera), Zootaxa 1026 (1), pp. 1-122 : 53-55

Robustagramma altifrons Cui and Marshall , new species

( Figs. 128–135 )

Body length 1.1–1.8 mm. General color brown to dark brown, moderately pollinose. Scutum with 2 or 4 inconspicuous grey dorsal vittae.

Head: Lower half of frons orange to redddish yellow, upper half reddish to dark brown. Face brown; gena and antenna reddish brown. Ocellar triangle, interfrontal strips and orbital strips slightly silvery. Frontal vitta between interfrontal plates gradually but distinctly protuberant from posterior to anterior margin. Interfrontal bristles distinctly small, brownish, in 3–5 pairs. Two orbital bristles, anterior orbital bristle ca. 2/3 as long as posterior. Uppermost orbital setula present between orbital bristles; lower orbital setulae small. Postvertical bristles over 2/3 as long as inner occipital bristle, slightly convergent or cruciate. Postocellar bristles absent. Face with a narrow central ridge, facial ridge between antennae conspicuously narrower than width of scape, and slightly depressed at middle. Eye height ca. 1.8–2.0 times genal height. Arista short, subequal to head height. Aristal hairs twice as long as basal width of arista. Palpus moderately thickened, maximum palpal width ca. 1/4 as long as palpus. Two preapical palpal bristles, ca. 1.5–2.0 times as long as maximum width of palpus.

Thorax: Prosternum narrow, bare. Dorsocentral bristles in 2 postsutural pairs, anterior dorsocentral bristles slightly longer than middle prescutellar acrostichal bristles. Acrostichal setulae in 6 rows between anterior dorsocentral bristles. Apical scutellar bristle ca. 1.8 times length of scutellum. Posterodorsal katepisternal bristle half as long as distance between bristle base and wing base; anterior katepisternal bristle very small. Halter knob pale to brown; stem pale. Length of second costal sector ca. 0.37–0.47X length of third. R 2+3 short and almost straight, distal 1/4–1/3 slightly curved forward. R 4+5 and costa ending together before wing apex. Discal cell with a short stump of vein CuA 1, ca. 0.5–2.0 times as long as width of vein. Tarsi and fore tibiae yellow. Mid tibia with a small dorsal proximal bristle, a small anterodorsal bristle near middle, and an anterodorsal, dorsal and posterodorsal distally; distal dorsal bristle small. Mid femur with an anterior subapical and a small posterodorsal apical bristle. Mid tibia of male also with an apicoventral and 4–6 short, stout ventral bristles on distal third; corresponding femur with a row of 3–5 ventral proximal bristles.

Male abdomen: All abdominal tergites uniformly brown and similar in length. Sternite 5 ca. 1.5 times as long as sternite 4, with a distinct arcuate borderline between dark anterior portion and pale posterior portion, and 3 or 4 pairs of short, stout bristles on borderline. Posteromedial portion of sternite 5 dark and shining, with several irregular rows of black scales on posteromedial margin. Epandrium short, dorsomedial length ca. 0.25–0.3X length of sternite 8. Surstylus mostly setose, tapering in posterior view. Cercus conspicuously shorter than surstylus, with 3–4 setulae on basal half. Disphallus broad, with a pair of dorsal whip­like sclerites. Postgonite with a concave apex. Ejaculatory apodeme small.

Female abdomen: Tergites 1–7 uniformly pigmented and entire. Sternite 7 longer than sternite 6. Sternite 8 reduced to 2 small sclerites, each with 2 or 3 small setulae. Sternite 10 pale, transverse, setulose. Three spermathecae, single one distinctly smaller than paired.

Holotype (♂, DEBU) and paratypes (3 ♂, 7 ♀, DEBU): UNITED STATES: Florida. Marion Co., Rd 80, Ocala Natl. For., sand­pine FIT, 10–12.vi.1984, S.A. Marshall.

Other paratypes: UNITED STATES: Florida. Marion Co., Zay Prairie , Ocala National Forest , carrion trap, 8–14.vi.1984, S.A. Marshall (4 ♂, DEBU) . Same data as previous label, but dated 14–18.vi.1984 (1 ♂, DEBU) . Marion Co., Ocala Natl. For., Silver Spring Wd , sand­pine FIT, 6–23.vi.1984, S.A. Marshall (2 ♂, 2 ♀, DEBU) . Okaloosa Co., 1 mi N Holt, Black­water River Natl. For., Turkey Oak , human dung trap, 23.x.1978, L. Stange (1 ♂, DEBU) . Volusia Co., Tomoka St. Pk. , oak­palm, diurnal mushroom trap, 19.vi.1984, S. A. Marshall (1 ♀, DEBU) . New Jersey. Burlington Co., 4 mi WNW Mt. Misery , pine­oak, carrion, 4–19.viii.69, A. Newton (2 ♂, DEBU) . Texas. Brazos Co., College Station, Lick Creek Park, post oak savanna by creek, malaise trap, 5–9.iv.2000, M. Buck (2 ♂, 2 ♀, DEBU) . Bastrop Co., Bastrop State Park , 24–27.v.1983, S.& J. Peck, oak woods, carrion traps (1 ♂, 1 ♀, DEBU) .

Etymology: The specific epithet refers to the protuberant frontal vitta of this species.

Comments: The female specimens from Texas differ slightly from the Florida specimens in having thicker spermathecal ducts.

Figures

FIGURES 128–135. Robustagramma altifrons sp. nov.: 128, dorsal view of left tibia; 129, posterior view of male terminalia; 130, lateral view of male terminalia; 131, lateral view of male internal genitalia; 132, male sternite 5; 133, dorsal view of female terminalia; 134, ventral view of female terminalia; 135, spermathecae.