Sarcophaga (Bulbostyla) Giroux & Wheeler

Giroux, Marjolaine & Wheeler, Terry A., 2010, Systematics of Bulbostyla, a new subgenus of Sarcophaga Meigen, and change of status for Robackina Lopes (Diptera: Sarcophagidae), Zootaxa 2553, pp. 35-59 : 37-39

Sarcophaga (Bulbostyla) Giroux & Wheeler subgen. nov.

Sarcophaga (Neobellieria) Blanchard in part: Pape (1996: 366).

Type species: Sarcophaga (Bulbostyla) cadyi Giroux & Wheeler sp. nov. (by present designation).

Diagnosis: Bulbostyla may be distinguished from other subgenera of Sarcophaga by male genitalic characters only. Males have the juxta wider than long and the hinge between the juxta and the phallic tube invaginated. The lateral styli have a large diameter and the tip of the median stylus is swollen. The phallic vesica has two lateral moderately long and sclerotized processes.

Description: Male: body length 9.0–13.0 mm.

Head: background color black or brown, usually with bronze or silvery pruinosity, sometimes yellowish or pinkish depending on the incidence of light. Postocellar setae medium to long, proclinate, hair-like, extending to level of paravertical setae. Inner vertical seta reclinate. Outer vertical seta as long as or slightly longer than upper postocular. Proclinate orbital setae absent; upper orbital setae reclinate. Number of medioclinate frontal setae variable, row distinctly curving outwards at lunule, often ending in more than one row of setae; weak interfrontal setae all along frontal vitta, sometimes spreading inwards on the vitta. Frontal vitta dark brown (usually matt black in S. yorkii ). Fronto-orbital plate with numerous scattered black setulae. Parafacial bronze or silvery pruinose, sometimes yellowish or pinkish depending on the incidence of light, with scattered black small setulae followed by long ones just before genal groove. Color of genal and postgenal hairs variable. Occipital setae white and usually with 2–4 rows of black setae below postocular setae. Antenna dark to light brown. Palpus pale to dark brown (sometimes yellowish in S. semimarginalis ).

Thorax: background color black or brown usually with bronze or silvery pruinescence, sometimes yellowish or pinkish depending on the incidence of light. Presutural acrostichal setae absent; 1 pair prescutellar acrostichal setae; 4–5 presutural dorsocentrals, slightly stronger than adjacent clothing setae; 4–5 postsutural dorsocentral setae, posterior two stronger than anterior 2–3; 1–2 presutural intra-alar setae (anterior one stronger) + 1–3 postsutural intra-alar setae (posterior one stronger); 1–2 + 3–4 supra-alar setae; anterior postpronotal seta present; 2 basal postpronotal setae. Proanepisternum usually bare. 2 postalar setae; intrapostalar setae reduced or absent. Postalar wall setose. Scutellum with 1 apical, 1 strong and long subapical, 2 basal (anterior one weaker) and 1 discal pair of setae. Variable number of strong anepisternal setae, upper two always shorter and declinate; 3 katepisternal setae, occasionally 2 or 4. Infrasquamal setulae present. Posterior spiracle subtriangular with anterior fin-shaped fringe usually dark brown (usually bronze in S. yorkii ) and posterior fringe usually paler.

Wing: membrane hyaline, cells at base often darkened by brown microtrichia (particularly in S. yorkii ). Veins pale to dark-brown. Tegula dark, pale to dark-brown pruinose, setose on about half its surface, with a short black bristle on outer margin and 2 long black bristles on inner margin. Basicosta pale, golden-beige pruinose; C extending to M, base strongly bristled with 2–3 stout bristles close to costagial break, usually with ventral row of equidistant minute setae extending to or just beyond R1. Weak costagial, humeral and subcostal breaks. Costal spine absent or vestigial. Subcostal sclerite and stem-vein golden-brown pruinose (dark brown to black pruinose in S. yorkii ). Base of stem-vein with cluster of golden-brown hairs dorsally. Axillary sclerites golden-beige pruinose (darker in S. yorkii ); R4+5 setulose at base dorsally and ventrally, ventral row often extending to proximal half. Bend of M acute, sometimes right-angled, bent part concave relative to cell r4+5, extension at bend usually present as a short fold darkened by dense microtrichia. Crossvein r-m sometimes slightly infuscated. CuA1 ending at wing margin as a fold with dense microtrichia. A1+CuA2 not reaching wing margin. A2 distinct as a fold darkened by dense microtrichia. Lateral margin of alula with fringe of hairs of various lengths. Calypters creamy white; upper calypter rather rounded, posterior margin with short white or brown hairs; lower calypter broadly expanded and angular, posterior margin rather straight. Hairs fringing calypters extending to distal margin of lower calypter.

Legs: background color dark brown or black. Fore and mid coxae covered with long hairs and strong setae. Hind coxae with 2–3 strong setae laterally and ventrally covered with moderately long to long hairs. Trochanters usually paler brown than femora. Fore femur sometimes with moderately long ventral hairs, with complete row of strong dorsal and posteroventral setae (longer in middle) and complete row of shorter posterodorsal setae. Fore tibia with 1 anterodorsal, 1 dorsal, 1 posterodorsal, 1 posterior, 1 posteroventral and usually 1 short ventral setae apically, 1 posterior seta on apical third, 3–5 strong anterodorsal setae on proximal part. Tarsomere length: 1>2>3>4<5, first and second hind tarsomeres with pad of fine bronze posteroventral and posterior setae. Mid femur with moderately long ventral hairs on proximal part, a row of moderately long posteroventral setae on apical half or third, and a complete row of moderately long to long anteroventral setae, with 3–5 strong mid anterior setae and 2–4 strong posterodorsal setae apically. Mid tibia with 1–2 moderately long posterodorsal setae on proximal third, sometimes with weaker setae interspersed, with 1–3 moderately long mid anterodorsal setae, sometimes with 1 moderately long to long anteroventral, 1 dorsal, 1 posterodorsal setae on apical third and setae of various lengths around apex. Hind coxa with 2–3 strong setae on lateral side, covered with long hairs, sometimes very dense. Hind trochanter with moderately long ventral setae. Hind femur and tibia straight, usually with moderately long anteroventral, ventral, and posteroventral hairs. Hind femur with 1 row of moderately long to long anteroventral setae, 1 row of moderately long to long posteroventral setae, 2–3 dorsal and posterodorsal setae on apical third, 1 complete row of moderately long to long anterodorsal setae, with second row restricted to proximal two-thirds (sometimes reduced or absent in S. cadyi and S. semimarginalis ). Hind tibia with 2–3 strong anterodorsal and posterodorsal setae (anterodorsal row with weaker setae interspersed), with 1 strong and sometimes 1–2 weaker anteroventral setae on apical half or third, with 1 dorsal, 1 anterodorsal, 1 anterior, 1 anteroventral, 1 ventral and 1 posteroventral setae of various lengths apically, apex with small pad of fine brown or black posteroventral and posterior setae.

Abdomen: elongated and slightly conical posteriorly. Background color black or brown with grey, bronze or silvery pruinosity. Tergites covered with small black setae dorsally, moderately long wavy hairs usually restricted to sternites 1–2 and ventral margin of tergites 3–5. Number of lateral marginal setae variable between tergites and between specimens. Median marginal setae on tergite 4 always present. Margin of tergite 5 often partly orange-reddish, row of setae at posterior margin often forming half circle spreading on apical third.

Terminalia: background color yellowish, cerci and syntergosternite 7+8 sometimes darker than epandrium. Sternite 5 with V-shaped emargination posteriorly and with a relatively long base anteriorly, cleft of posterior margin with moderately dense, strong black setae, apical parts with long hairs, window present and sometimes forming an elevation anteriorly on base. Tergite 6 vestigial or absent. Syntergosternite 7+8 with anterodorsal emargination and with spiracle 7 dorsolateral. Epandrium globose, square in lateral view but with posteroventral extension partly covering cerci in lateral view. Surstylus triangular (with a small posteroventral projection in S. yorkii ), proximal surface bare. Cercal base clothed with long black hairs, cercal prong stout and blunt, straight in profile, covered with short to moderately long hairs. Bacilliform sclerites reduced. Hypandrial arms not fused in posterior view. Postgonal apodeme reduced to a more or less oval dorsal sclerite. Pregonite with minute setulae along anterior surface, usually with a pointed lateral extension. Postgonite with a short subapical bristle and with a number of small setulae posteriorly. Vesica sclerotized, with two lateral moderately long sclerotized processes. Harpes sclerotized, short and rather round, fused or partly fused to phallic tube. Lateral stylus coiled at base, with large diameter (particularly obvious on dried specimens) and covered with strong microserrations, longitudinal cleft opened all along internal side. Median stylus bifurcate, without opening, bulbous and forming two short processes apically. Hinge between juxta and phallic tube invaginated. Juxta sclerotized, fused to median stylus, wider than long.

Female: body length 10.0–11.5 mm. Differs from male as follows:

Head: two pairs of proclinate orbital setae present. Number of medioclinate frontal and interfrontal setae sometimes fewer than in male.

Thorax: apical scutellar setae absent.

Legs: fore femur without moderately long ventral hairs. Mid femoral organ present. Hind tibia without long posteroventral wavy hairs.

Abdomen: rounded and slightly conical posteriorly. Tergites covered with small black setae dorsally and ventrally, with relatively long hairs restricted to ventral margin of tergites. Margin of sternite 2 usually with 4 strong bristles. Posterior margin of sternite 3 sometimes with a few strong bristles.

Terminalia: tergite 6 narrowly membranous mid-dorsally. Spiracles 6 and 7 distinct. Sternites 6–8 not fused. Sternite 8 reduced to a weak sclerotized patch covered with moderately long setae and hairs on mid posterior margin. Sternite 10 membranous and covered with short to moderately long setae. Cerci distinct.

Etymology: from the Latin bulbosus (bulb) and stylus. The name refers to the swollen tip of the median stylus. The subgeneric name is feminine.

Biology: Most species of Bulbostyla are known from very few specimens, and associated biological data are almost non-existent. Several specimens were collected on mountain summits, and this hilltopping behavior may be common to most or all species in the subgenus.

Remarks: Tergites 4 and 5 are partially fused in the only female of S. cadyi , although this is apparently an aberrant specimen. We also examined 12 other females that probably belong to Bulbostyla but could not be associated with males. Three of the females were dissected and all have sternite 8 reduced to a sclerotized patch covered with moderately long hairs on the mid posterior margin and sternite 7 desclerotized on its middle part (as in S. semimarginalis ). Those character states may be synapomorphic for the subgenus although further investigation is needed.