Schildia microthorax Aldrich, 1923

Dikow, Torsten & Bayless, Keith M., 2009, Taxonomic revision of the genus Schildia Aldrich, 1923 (Diptera: Asilidae: Leptogastrinae) with the description of new extant and extinct species, Insect Systematics & Evolution 40, pp. 253-289 : 280-282

Schildia microthorax Aldrich, 1923 ( Figs 2–8 , 28–30, 36–37) ( Aldrich, 1923: 4)

( Carrera 1944: 87; Hull 1962: 314; Farr 1962: 194; Martin 1968b: 5; Martin 1975: 189; Fisher in press)

Diagnosis. This species is distinguished from its congeners by the medially very narrow face, as narrow as width of an adjacent ommatidium at narrowest point, the entirely brown metathoracic tibia, and R1 reaching C at or distal to R5 joining C ( Fig. 36 ).

Redescription. Head: Face silver to yellow pruinose, narrow, narrower than adjacent ommatidium; mystax light brown, 2 setae; vertex wide, wider than face at clypealfacial margin, yellow pruinose; occipital triangle apruinose, distance between triangle and median eye margin more than adjacent ommatidium; occiput laterally light brown pruinose, median dorso-ventral stripe silver pruinose; postocular setae brown; proboscis light brown; Antennae: scape and pedicel yellow to light brown, yellow or light brown setae dorsally and ventrally; postpedicel predominantly brown, silver pruinose, about 1.5 times as long as combined length of scape and pedicel; stylus dark brown, as long as postpedicel, composed of 1 element.

Thorax: Predominantly brown (sometimes red medially), silver pruinose; antepronotum, postpronotum and median postpronotal lobes silver pruinose; lateral postpronotal lobes apruinose, yellow; scutum brown, predominantly apruinose, only extreme lateral margin and posterior part silver pruinose, 2 light brown longitudinal stripes lateral to median line reaching posterior margin; presutural dc setae: 2–4 short, 1 long, postsutural dc setae: only a few short anteriorly oriented setae close to posterior margin, 5–6 short acr setae, 1 npl and 1 spa seta; anepisternum and anepimeron yellow dorsally and brown ventrally, silver pruinose, few yellow anepisternal setae on anterior and dorsal margins; proepimeron, katepisternum, katepimeron, and meron+metanepisternum brown, predominantly silver pruinose, katepisternum with antero-medial apruinose spot, metkatepisternum yellow, silver pruinose; scutellum brown, silver pruinose, apical scutellar setae absent; Legs: light yellow to brown; coxae light yellow; trochanters light yellow, small brown area ventrally; pro and mes femora light yellow proximally, light brown distally, met femur light yellow proximally, brown distally, clubbed in distal 1/3, yellow transverse band at proximal margin of club, scattered brown macrosetae on pro and mes femora, met femur with distinct rows of brown macrosetae; pro and mes tibiae light yellow to light brown, met tibia brown throughout with distal part darker, all tibiae with yellow to light brown erect macrosetae in rows, pro and mes tibiae with 3 long apical macrosetae, met tibia with 2 median and 2 apical macrosetae; tarsus light brown to brown, proximal tarsomere always longer than 2 following tarsomeres combined, short and long macrosetae on all tarsomeres; pro and mes empodia 1/3 and met empodium 1/5 as long as median claw; pro and mes median claw 3/4 of lateral claw, met median claw 1/2 of lateral claw; Wings ( Fig. 36 ): length = 3.4–5.2 mm; few microtrichia, trichoid spicules short, symmetrical dorsally and ventrally, 12–14 on M1 between r-m and diversion of M 1 and M 2; cell d small, terminating in M 2 and M 3, r-m situated proximal to separation of M3 and CuA1; R1 nearly parallel and close to C, R1 reaching C at or distal to R5 joining C, R2+3 straight proximally and smoothly arching posteriad distally; halter light yellow, knob dark brown, length = 0.7–1.0 mm.

Abdomen: Brown; T2 length = 2.4–3.7 mm, T2 with yellow transverse band medially, T2–3 with short, erect, evenly spaced macrosetae, remaining T with irregularly spaced and longer macrosetae T7–8 with large lateral sensory areas, nearly touching medially on T8; Male terminalia ( Figs 28–30 ): epandrial halves fused medially, distal tip straight, pointed, narrow lobe extending beyond cerci; epandrium and hypandrium fused proximally, gonocoxite and hypandrium fused to form a gonocoxite-hypandrial complex; Aedeagus: protruding from hypopygium, distal tip of dorsal aedeagal sheath distinctly arched ventrally, prong dorso-ventrally flattened; Female genitalia: spermathecae occupying only segment 8, individual spermathecal ducts long and coiled; spermathecal reservoirs not sclerotized, as wide as individual ducts, forming a coil.

Type material. The ♂ holotype is labeled “ Higuito San Mateo CR / Pablo Schild Coll / Type No. 25308 U.S. N.M. (number handwritten, red label) / Schildia microthorax Ald. (handwritten, black border)” ( USNM). The specimen is double mounted (wooden minuten in foam), and is in good condition (right meso- and left metathoracic legs broken) . The ♀ paratype is labeled “ Higuito San Mateo CR / Pablo Schild Coll / Allotype No. 25308 U.S. N.M. (number handwritten, red label) / Schildia microthorax Ald. Allotype (handwritten, black border)” ( USNM). The specimen is double mounted (minuten in foam) and is in good condition (postpedicel broken) .

Specimens. Brazil: Parà: 1♀ Rio Xingo Camp, ca 60 km S Altamira , 03°39’S 052°22’W, 2–8.x.1986, P. Spangler O. Flint ( USNM) ; Costa Rica: Heredia: 1? Basilia , 10°18’N 084°00’W ( INBIO) ; 1♀ F. La Selva , 3 km S Puerto Viejo , 10°26’N 084°01’W, 14.iv.1984, H. Hespenheide ( EMF) , 1♀ 1♂ Higuito , 09°57’N 084°33’W, -.-.-, P. Schild (holotype, paratype, USNM) , Puntarenas: 1♀ Parque Nacional Corcovado, Estancia Sirena , 08°28’N 083°36’W, 25.iii.1981, H. Hespenheide ( EMF) , 1♂ Parque Nacional Corcovado, Estancia Sirena , -. xii.1989, G. Fonseca ( INBIO) , 1♂ Peninsular Osa, 5 km N Puerto Jimenez , 08°33’N 083°30’W, 1.ii.1993, P. Hanson ( EMF) ; Panama: 1♀ Barro Colorado Island , 09°09’N 079°54’W, 15.vii.1978, E. Fisher ( EMF) , 1♀ Barro Colorado Island , 18–23.v.1967, R. Akre ( FSCA) , 1? Camp Gaillard , 09°30’N 079°40’W, 1.i.1925, Shropshire ( USNM) ; Peru: Madre Dios: 1? Tambopata Reserve , 30 km SW Puerto Maldonado , 12°43’S 069°10’W, 20.xi.1982, E. Fisher ( EMF) , 1♀ Monsoon Valley, Tingo Maria , 09°12’S 076°12’W, 23.xii.1954, E. Schlinger E. Ross ( FSCA) ; Trinidad and Tobago: 1♀ St. George, Arima , 10°39’N 61°19’W, 27.i.1976, A. Stubbs ( BMNH) ; Venezuela: 1♀ 1♂ Zulia, Los Angeles del Tucuco , 10°14’N 071°54’W, 15–16.iv.1981, E. Grissell ( EMF) .

Distribution. Brazil, Costa Rica, Panama, Peru, Trinidad and Tobago, Venezuela ( Fig. 37 ). Biodiversity hotspot/high-biodiversity wilderness area: Mesoamerica/Amazonia ( Fig. 37 ).

Remarks. This is the type species of Schildia . It is the best represented species in collections, and has the most widespread distribution from Costa Rica in the north to Brazil in the south.

Figures

Figs 2–4. SEM micrographs of wing of Schildia microthorax (EMF, Costa Rica) with veins labeled. (2) Distal tip of wing; (3) detail of trichoid spicules; (4) posterior margin of wing. Scale bars = 50 µm.

Figs 5–8. SEM micrographs of head and metathoracic tarsus of Schildia microthorax (EMF, Costa Rica). (5) Head, anterior view; (6) head, dorsal view; (7) tarsus, lateral view; (8) detail of claws, lateral view. Scale bars = 100 µm.

Figs 25–36. Male terminalia with gonostyli (dark grey) and lateral processes of gonostyli (light grey) shaded in lateral views, abdominal T8, and wings of Schildia species. (25–27) Male terminalia of S. malaya sp.n.: 25, lateral; 26, dorsal; 27, ventral. (28–30) Male terminalia of S. microthorax. 28, lateral; 29, dorsal; 30, ventral. (31–33) Male terminalia and T8 of S. fragilis: 31, lateral; 32, dorsal; 33, ventral; 34, T8 dorsal. (35–36) Wings: 35, S. malaya sp.n.; 36, S. microthorax. Scale bars = 1 mm.

Fig. 37. Map of the Neotropical region with biodiversity hotspots and wilderness areas, shaded in grey, showing distribution of Schildia guatemalae (triangle), S. jamaicensis (square), †S. martini sp.n. (star) and S. microthorax (circle). Open symbols, type localities.