Schildia Aldrich, 1923: 4

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 : 258-261

Schildia Aldrich, 1923: 4

Type species Schildia microthorax Aldrich, 1923 by original designation.

Shannomyioleptus ( Carrera, 1944: 86) . Type species Shannomyioleptus fragilis Carrera, 1944 by original designation.

Schildia ( Carrera 1944: 86; Carrera 1950: 108; Hull 1962: 313; Martin 1965: 110; Martin 1968b: 5; Martin 1975: 189; Artigas & Papavero 1988: 98, 102; Nagatomi et al. 2002: 38; Fisher in press).

Schildia subgenus Shannomyioleptus ( Hull, 1962: 314) .

Diagnosis. Schildia is distinguished from other Leptogastrinae genera by the long, regularly spaced trichoid spicules on dorsal and ventral sides of at least veins R and M ( Fig. 2 ), the asymmetrical tarsal claws wherein the median claw is shorter than the lateral claw ( Fig. 8 ), stipites with two long setae posteriorly, long posteriorly oriented presutural, and sometimes postsutural, dorsocentral setae on the scutum, the medially fused male epandrium (in most species) ( Fig. 32 ), the absence of a surstylus on the male epandrium ( Fig. 13 , but see below), and the very elongate, slender abdomen and gracile appearance ( Figs 9, 12 ).

Remarks. The genus was named in honor of Pablo Schild, who collected the type specimens of the genus in Costa Rica, and is here treated feminine in gender.

Redescription. Head: Brown or black; face silver or grey pruinose, sometimes apruinose in dorsal half; face either narrower or wider than adjacent ommatidium ( Fig. 5 ); mystax always light colored from light yellow to light brown, either 2 or 4 setae, if 4 setae median pair shorter than outer; facial swelling indistinct, not discernible in lateral view; vertex either narrower or wider than face at clypeal–facial margin ( Fig. 6 ), silver or grey pruinose; occipital triangle apruinose, distance between triangle and median eye margin either less or more than adjacent ommatidium ( Fig. 6 ); occiput generally pruinose, sometimes ventral half apruinose; postocular setae always present, often very long and oriented anteriorly; proboscis brown; stipites with 2 long setae posteriorly; Antennae: scape and pedicel generally light yellow, with setae dorsally and ventrally; postpedicel broadest medio-distally, dorsal margin straight and ventral margin concave ( Fig. 5 ), light yellow to brown, silver pruinose, between 1.5–2.0 times as long as combined length of scape and pedicel; stylus brown, 1/6 of postpedicel to as long as postpedicel, composed of either 1 or 2 elements, inserted on dorso-distal margin ( Fig. 5 ).

Thorax: Predominantly brown, generally silver or brown pruinose, apruinose areas sometimes present; mesothorax antero-medially somewhat cone-like and projecting anteriorly over median postpronotal lobes ( Fig. 12 ); prosternum separated from proepisternum; antepronotum, postpronotum and median postpronotal lobes either apruinose or silver pruinose; lateral postpronotal lobes always apruinose, generally lighter colored than scutum ( Fig. 12 ); scutum brown or yellow, predominantly apruinose, only lateral and posterior margins pruinose to varying extent ( Fig. 12 ); presutural dc setae: between 2–5 posteriorly oriented pairs of varying length, postsutural dc setae: generally only short anteriorly oriented setae, sometimes long posteriorly oriented setae, sometimes setae absent, 2–6 acr setae anteriorly, 1 npl and 1 spa seta, pal seta absent; pleurae yellow or brown, generally pruinose, sometimes with apruinose areas on anepisternum, katepisternum, or meron+metanepisternum, few yellow anepisternal setae on anterior and dorsal margins; scutellum usually brown, silver pruinose, apical scutellar setae generally very short, sometimes longer; postmetacoxal bridge present, visible suture medially; Legs: light yellow to light brown ( Fig. 12 ); coxae either light yellow or brown, pruinose; trochanter light yellow with ventral sides sometimes brown; pro and mes femora light yellow with either 1 or 2 transverse brown bands, met femur light yellow proximally, light brown to brown in remaining part, clubbed in distal 2/5 to 1/2, club always brown with yellow transverse band at proximal margin of club ( Figs 9–12 ), scattered brown macrosetae on pro and mes femora, met femur with distinct rows of brown macrosetae; pro and mes tibiae light yellow with either 1 or 2 light brown transverse bands, met tibia brown with or without median yellow transverse band of different width, from 1–3 times as wide as width of tibia, all tibiae with yellow to light brown erect macrosetae in rows, pro and mes tibiae with 2–3 long apical macrosetae, met tibia with 1–5 median and 1–2 apical macrosetae; tarsus light yellow to light brown, proximal tarsomere always longer than 2 following tarsomeres combined ( Fig. 7 ), short and long macrosetae on all tarsomeres; pro and mes empodia generally minute sometimes 1/3 as long as median claw, met empodium from minute to more than half as long as median claw; median claw always shorter than lateral claw, 1/2–3/4 of lateral claw ( Fig. 7, 8 ); Wings ( Figs 11 , 35, 36 ): length = 3.4–5.2 mm, sometimes 5.3–7.8 mm; hyaline, generally few microtrichia scattered on wing, sometimes microtrichia densely arranged throughout, at least R and M veins with conspicuous, regularly spaced, and curved trichoid spicules that can be very short to long ( Fig. 2 ), predominantly symmetrical dorsally and ventrally but sometimes asymmetrical, usually 12–26 on M1 between r-m and diversion of M1 and M 2, two species 40–50; cell d generally small and terminating in M 2 and M 3 ( Figs 12 , 36 ), sometimes large and terminating in M1 and M2, only M2, or M1, M2 and M3 ( Figs 11 , 35 ), r-m generally situated proximal to separation of M3 and CuA 1, sometimes distal to separation; R 1 generally reaching C proximal to R 5 and M 1 joining C ( Fig. 35 ), sometimes distal to R5 and M1 joining C ( Fig. 36 ), R2+3 generally straight proximally and smoothly arching posteriad distally ( Fig. 36 ), sometimes sinuous and posteriormost point at mid-length ( Fig. 35 ); all marginal wing cells broadly open ( Figs 35, 36 ); pterostigma absent; alula absent; halter long, light yellow, knob dark brown.

Abdomen:Predominantly brown;T2 length = 1.0–4.0 mm, one species 4.9– 5.1 mm, T2 generally with yellow transverse band medially ( Fig. 12 ), sometimes yellow areas on anterior or posterior margins of T3–6, T2–3 with short, erect, evenly spaced macrosetae, remaining T with irregularly spaced and longer macrosetae; T7–8 generally with lateral sensory areas of unknown function that are best seen after maceration ( Fig. 34 ), absent in 2 species; Male terminalia: epandrium usually a single sclerite, fused medially ( Figs 17, 20, 23 , 29, 32 ), sometimes separated medially and joining proximally ( Figs 14 , 26 ), always with finger-like distal projection of varying length and shape, surstyli absent ( Fig. 13 ) (in S. fragilis an indentation at the base of the finger-like distal projection of the epandrium might suggest that this projection is the surstylus which is secondarily fused to the epandrium); hypandrium and gonocoxites always fused, but sometimes with visible sutures ( Fig. 16 ), or forming a gonocoxite-hypandrial complex ( Figs 13, 22 , 25, 28, 31 ); lateral processes of gonostyli present ( Figs 13, 16, 19, 22 , 25, 28, 31 ); gonostyli situated apically on gonocoxite or gonocoxite-hypandrial complex; Aedeagus: sometimes long and protruding from hypopygium ( Figs 13 , 25, 28 ), sometimes short ( Figs 16, 19, 22 , 31 ); Female Genitalia:ovipositor unspecialized, composed of segments 8 and following; S8 invaginated medio-distally; furca triangular, with two sclerotized processes laterally; bursa copulatrix short, tube-shaped, widest medially; 3 spermathecae of same size generally occupying only segment 8, in one species reaching into segment 7, individual spermathecal ducts generally long, coiled, in one species more or less straight; spermathecal reservoirs generally as wide as individual spermathecal ducts, unsclerotized, in one species clearly sclerotized and wider than ducts.

Distribution. Species of Schildia are known from the Afrotropical, Neotropical, and Oriental regions. The center of diversity is found in the Neotropical region with seven species ( Fig. 1 ): from Guatemala in the north to south-eastern Brazil in the south; Jamaica is the only Caribbean island that is currently inhabited whereas one extinct species is preserved in Dominican amber and occurred on Hispaniola during the Tertiary: Miocene ( Figs 1 , 37). Within the Afrotropical region Schildia is only known from a single species found on Madagascar ( Fig. 1 ) and has not been recorded on mainland Africa although the Leptogastrinae fauna has been extensively studied by the senior author (unpublished data). Within the Oriental region a single species is recorded from the Malaysian peninsula ( Fig. 1 ).

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.

Figs 13–24. Male terminalia of Schildia species with gonostyli (dark grey) and lateral processes of gonostyli (light grey) shaded in lateral views. (13–15) S. adina sp.n.: 13, lateral; 14, dorsal; 15, ventral. (16–18) S. gracillima: 16, lateral; 17, dorsal; 18, ventral. (19–21) S. guatemalae: 19, lateral; 20, dorsal; 21, ventral. (22–24) S. jamaicensis: 22, lateral; 23, dorsal; 24, ventral. Scale bar = 1 mm.

Figs 9–12. Photographs of extinct and extant species of Schildia. (9) †Schildia martini sp.n. (holotype, AMNH Luzzi); (10) †Schildia martini sp.n. (paratype, AMNH DR-V-7); (11) Schildia adina sp.n. preserved in Malagasy copal (Coll. Stuke). (12) Schildia fragilis (USNM, Peru).Scale bars = 1 mm.This figure is published in colour in the online edition that can be accessed via http://www.brill.nl/ise

Fig. 1. Map of the world with extant and extinct distribution of Schildia indicated with solid circles. Note the restricted Old World distribution in Madagascar and Malaysia.