Spinalobus rodmani, Webb, Donald W., 2007

Webb, Donald W., 2007, A new genus and new species of Nearctic Therevidae (Insecta: Diptera) from Southern New Mexico, Zootaxa 1495, pp. 41-46 : 43-45

Spinalobus rodmani spec. nov.

Diagnosis

Spinalobus rodmani can be separated from other New World genera in the male eyes dichoptic; the scape narrower and shorter than the flagellum; the mesonotum with dorsocentral macrosetae; the prosternum with setae in and around the central depression; the metanepisternum lacking setae; the scutellum with one pair of macrosetae; the costal vein of the wing circumambient; the midcoxa lacking posterior setae; the wing cell m3 closed and petiolate; and the ventral lobe of the male genitalia with several large, elongate macrosetae ( Fig. 2 ).

Description of holotype male (MEI 051228).

Body length 7.2 mm.

Head. Length 0.90 mm. Face extending moderately beyond eyes. Ocellar tubercle dark reddish brown, pubescence light gray; not raised above dorsal level of occiput; setae black, elongate. Eyes dark reddish brown; dichoptic, separated by distance greater than width of ocellar tubercle; ommatidia smaller dorsally and laterally. Frons broad, rectangular, sides almost parallel, dark reddish brown, pubescence whitish gray, dense; setae black, elongate, scattered over entire frons; area lateral to antennal base lacking setae or black pubescent band. Antenna dark brown, pubescence on scape gray, antenna/head length 0.70; scape cylindrical, length 0.22 mm, width 0.16 mm, length/width 1.4, scape/pedicel length 2.4, scape/flagellum width 0.84, setae dark reddish brown grading into dark reddish brown macrosetae, absent on medial surface; pedicel globular, length 0.09 mm, width 0.14 mm, length/width 0.64, setae dark reddish brown, short, absent on medial surface; first flagellomere oval, length 0.24 mm, width 0.19 mm, second flagellomere small, cylindrical, length 0.02 mm, width 0.03 mm, third flagellomere small, tapered posteriorly, length 0.06 mm, width 0.03 mm, apical style 0.02 mm, flagellum length 0.32 mm, length/width 1.7, flagellum/scape length 1.5. Parafacial broad, dark reddish brown with pubescence white on dorsal half, setae absent. Maxillary palpus one-segmented, dark brown, cylindrical, thick; length 0.44 mm, width 0.13 mm, length/width 3.4; setae black, elongate. Gena dark reddish brown, pubescence white; setae white, elongate. Occiput dark reddish brown, pubescence white; setae white, elongate, absent dorsally, macrosetae dark reddish brown, abundant, scattered. Postocular macrosetae dark reddish brown, in single row.

Thorax. Macrosetae 3 np, 2 sa, 1 pa, 2 dc, 1 sc. Mesonotum dark reddish brown, pubescence whitish gray; vittae dull brown separated by whitish gray pubescence; setae white, short, subappressed. Postpronotal lobe concolorous with mesonotum; setae white, short. Cervical sclerite dark reddish brown, pubescence white; setae and macrosetae absent. Prosternum with white, elongate setae in and around medial depression. Pleurae dark reddish brown, pubescence white with glossy area on dorsal half of anepisternum; setae whitish yellow on anepisternum, laterotergite, and scutellum, absent on proepimeron, katepisternum, anepimeron, meron, metanepisternum, and metakatepisternum. Wing. Length 5.2 mm, width 1.7 mm, length/width 3.1. Membrane pale smoky brown; pterostigma dark brown. Setulae absent on R1. M1, M2 and M3 originate separately from discal cell. Cells m3 and cup closed, petiolate. Anal angle broadly rounded. Halter dark brown. Legs. Coxa dark reddish brown, pubescence white, dense; setae absent posteriorly on midcoxa; hindcoxa with short, rounded anterior knob; setae white; apical macrosetae absent on fore– and midcoxa, dark reddish brown on hindcoxa, forecoxa with 3 anterior macrosetae, midcoxa with 2 anterior macrosetae, hindcoxa with 1 posterolateral macrosetae. Femora dark reddish brown, apical third dark yellow; ventral setae white, dorsal setae white, lanceolate, appressed; av 7:3:10, pv 7:5:5. Tibiae and tarsi dark reddish brown; foretibia with several short posteroventral macrosetae.

Abdomen. Dark reddish brown, pubescence white across posterior margin of tergites 1–3 and 5; dorsal setae dark brown, appressed on dark reddish brown areas, white elongate laterally and across posterior margins of tergites 1–3 and 5. Terminalia . Tergite 8 ( Fig. 1 ), median length narrow (0.04 mm); setae dark brown, with a few setae medially on posterior margin. Sternite 8 ( Fig. 2 ), posterior broadly rounded. Epandrium ( Fig. 1 ) quadrate, wider than medial length, posterolateral margin short, broadly pointed, setae dark reddish brown. Cerci ( Fig. 1 ) free, ending basal to hypoproct, setae yellow, short, fine. Hypoproct ( Fig. 1 ) broad, posterior margin slightly emarginate, ending distal to posterolateral margin of epandrium and cerci. Hypandrium ( Fig. 2 ) dark brown, strap-like. Gonocoxite ventral view ( Fig. 2 ) separated medially, broad, rectangular with short outer gonocoxal process posterolaterally, not extending posteriorly beyond gonocoxite, setae brown laterally; lateral view quadrate, rounded posteriorly; dorsal view ( Fig. 3 ), gonocoxal apodeme narrow, elongate, not extending anteriorly beyond anterior margin of gonocoxite; ventral lobe ( Fig. 2 ) large, broad, extending well beyond gonocoxite, with several large dark yellow spinous macrosetae. Gonostylus ( Fig. 3 ) narrow, elongate, extending well beyond gonocoxite. Aedeagus with dorsal apodeme ( Fig. 4 ) broad, quadrate with posterolateral expansion; ventral apodeme ( Fig. 5 ) tapered anteriorly, extending to anterior margin of dorsal apodeme; distiphallus lateral view ( Fig. 6 ) curved ventrally at 90° angle; ejaculatory apodeme ( Fig. 4 ) tapered anteriorly, posterior third bulbous; lateral ejaculatory processes absent.

Female

Variation (n = 7).

Body length 8.8–10.0, 9.3 mm.

Head. Length 1.12–1.24, 1.17 mm. Frons with dense gray pubescence; setae black, elongate, scattered over entire frons. Antennal/head length 0.62–0.71, 0.65; scape length 0.28–0.32, 0.30 mm, width 0.16–0.18, 0.18 mm, length/width 1.6–1.8, 1.7, scape/pedicel length 2.8–4.3, 3.4, scape/flagellum width 0.7–1.0, 0.8; pedicel length 0.07–0.11, 0.09 mm, width 0.16–0.18, 0.17 mm, length/width 0.44–0.61, 0.52; flagellum length 0.34–0.40, 0.37 mm, width 0.18–0.24, 0.22 mm, length/width 1.5–2.0, 1.7, flagellum/scape length 1.2–1.3, 1.2. Maxillary palpus length 0.44–0.54, 0.49 mm, width 0.12–0.16, 0.14 mm, length/width 2.9–4.5, 3.1.

Thorax. Macrosetae 3–4 np, 1–2 sa, 1 pa, 1–2 dc, 1 sc. Mesonotum with a mixture of short, subappressed whitish yellow and black setae. Wing. Length 6.2–7.3, 6.7 mm, width 2.0–2.7, 2.2 mm, length/width 2.6–3.2, 3.0. Legs. Forecoxa with 3–5 anterior macrosetae, midcoxa with 2–3 anterior macrosetae.

Abdomen. Dark reddish brown, pubescence white across posterior margin of tergites 1–3 and dorsolaterally on tergite 5; dorsal setae dark brown, appressed on dark reddish brown areas, white elongate laterally and across posterior margins of tergites 1–3. Terminalia (MEI 051271). Median lobe of tergite 9 with dark reddish brown setae. Sternite 8 with sclerotized aedeagal guide. Furca ( Fig. 7 ) oval, anterior margin closed, anterolateral projections short; length 0.50 mm, width 0.36 mm. Common spermathecal duct shorter than furca, trifurcating into two spermathecal ducts and a medial spermathecal sac. Spermathecae spherical.

Immature stages

Unknown.

Distribution

Spinalobus rodmani is known from New Mexico, USA.

Habitats and Phenology

Spinalobus rodmani has been collected from mid-September until early October. This collecting period is late in the season for most species of therevids in the United States.

Specimens examined

Type specimens. The holotype male of Spinalobus rodmani Webb is labeled “N. MEX. Dona Ana Co, 2.3mN Mesquite exit, E side I-10, 4000’, 23.IX.1982, GS Forbes” (MEI 051228) and is deposited in the INHS collection. Other specimens. PARATYPES. UNITED STATES. NEW MEXICO. Doña Ana County. 3.7 km N Mesquite exit, East side I-10, 1219 m, 18.IX.1981, 1Ψ MEI 0 51275 ( NMSU); 19.IX.1982, Forbes, G.S., 1Ψ MEI 0 51271 ( MEIC); 23.IX.1982, 3Ψ MEI 0 50607 ( INHS), 0 51227 ( USNM), 0 51267 ( NMSU); 17.X.1982, 1Ψ MEI 0 51257 ( NMSU); 4 km N Mesquite, 2.X.1982, Lightfoot, D., 1Ψ MEI 0 51243 ( NMSU).

Figures

FIGURES 1 – 7. Spinalobus rodmani. 1. tergite 8, epandrium, cerci, hypoproct, dorsal view. 2. sternite 8, hypandrium, gonocoxite, ventral view. 3. gonocoxite dorsal view. 4. aedeagus dorsal view. 5. aedeagus ventral view. 6. aedeagus, lateral view. 7. female reproductive organs. Scale = 0.1 mm. Abbreviations: C = cercus, CSpD = common spermathecal duct, DA = dorsal apodeme, EA = ejaculatory apodeme, Epa = epandrium, F = furca, Gx = gonocoxite, GxA = gonocoxal apodeme, Gs = gonostylus, Hpt = hypoproct, H = hypandrium, Dp = distiphallus, S 8 = sternite 8, Sp = spermatheca, SpS = spermathecal sac, T 8 = tergite 8, VA = ventral apodeme, VL = ventral lobe.