Antrops quadrilobus, KITS & MARSHALL, 2013

KITS, JOEL H. & MARSHALL, STEPHEN A., 2013, <p class = " HeadingRunIn " align = " left "> <strong> Generic classification of the Archiborborinae (Diptera: Sphaeroceridae), with a revision of <em> Antrops </ em> Enderlein, <em> Coloantrops </ em> gen. nov., <em> Maculantrops </ em> gen. nov., <em> Photoantrops </ em> gen. nov., and <em> Poecilantrops </ em> gen. nov. </ strong> </ p>, Zootaxa 3704 (1), pp. 1-113 : 75-77

Antrops quadrilobus group

The A. quadrilobus group is a clade of nine species. Synapomorphies for the species group are the reduction or loss of the presutural dorsocentral bristle and the shape of male sternite 5, which has a broad anterior apodeme with a dorsal keel and posterolateral corners produced with tufts of setae. The group is also characterized by an extensively shiny scutum. As species in this group are very similar in external morphology, species descriptions are abbreviated and only include characters which differ between species.

Description. Head colour and microtomentum variable. Face evenly sclerotized, ventral margin straight, lunule small. Occiput narrow below occipital foramen. Gena about 0.8X height of eye. Clypeus narrow, slightly produced. Palpus with dark setae concentrated along lateral margin. Prementum well-developed, circular, about 0.5X height of head. Labellum with 12 pseudotrachea. Scape very short, with 1–2 dorsomedial setulae; pedicel subtriangular, medial bristles slightly longer than outer; first flagellomere round, slightly pointed dorsoapically; arista dorsolateral, preapical, 2-segmented, about as long as head width, short-plumose. Chaetotaxy: orbital bristles in two lateroclinate pairs; irregular orbital setulae along orbital plate; interfrontal setae in 4–6 medioclinate pairs; ocellar bristles lateroproclinate, just anterior to median ocellus; irregular, very short ocellar setulae; inner vertical bristles inclinate; outer vertical bristles lateroreclinate; postocellar bristles as long as ocellar bristles, slightly proclinate; postvertical bristles small, cruciate; setae on median occipital sclerite short, medioclinate; postocular setae in a complete row with an incomplete row of occipital setae behind; vibrissa strong, as long as head; 1 subvibrissal bristle; 1 upturned anterior genal bristle; genal setae in 2–3 rows.

Thorax black, mostly shiny. Scutum with microtomentum along lateral margin, anepisternum with microtomentum along posterior margin, katepisternum with microtomentum on anterior third and ventral margin except shiny spot behind fore coxa, metapleuron with microtomentum between posterior spiracle and hind coxa, anepimeron and laterotergite covered with microtomentum. Halter whitish, brown below knob. Chaetotaxy: postpronotum with a single bristle; notopleuron with two bristles, posterior about 0.5X length of anterior; one presutural and one postsutural intra-alar bristle; one long postalar bristle in line with intra-alars and a shorter postalar between this and scutellum; three dorsocentral bristles (one presutural and two postsutural), presutural very short, barely or not distinguishable from surrounding setae; acrostichal setae in 6–8 irregular rows; scutellum with 2 pairs of scutellar bristles; proepisternum with several small setulae; katepisternum with a single large dorsal bristle and irregular setae ventrally.

Wing membrane pale brown, crossveins may be surrounded by a slightly darker cloud. Vein M reaching wing margin, CuA 1 extending somewhat past crossvein dm-cu, not reaching wing margin, A 1 +CuA 2 diverging from CuA 1, distal part not vascularised, not reaching wing margin. Calypter with a dense marginal patch of flattened setae.

Legs black, trochanters and tarsi yellow to brown. Femora and tibiae mostly shiny, anterior face of fore femur and tibia covered with microtomentum. Fore femur with dorsal and ventral rows of long, thin erect setae. Fore tibia with a preapical dorsal bristle. Fore basotarsomere with a small apical spur in males. Mid femur with a row of anterior bristles. Mid tibia with row of anterodorsal, 1 anteroventral, 1 posteroventral, 5 subapical bristles. Hind femur with several dorsal and ventral bristles near apex. Hind tibia with a long preapical dorsal bristle and 2–3 ventroapical bristles.

Abdominal tergites black, syntergite 1+2 entirely covered with microtomentum, posterior tergites with less microtomentum, tergites 4–5 usually with only basal third covered. Sternites weakly sclerotized in female, weakly to heavily sclerotized in male. Pleural membrane with setae on segments 2–5.

Male postabdomen: Sternite 5 generally similar between species, with lateral sides curved, posterolateral corners projecting with tufts of long setae, anterior apodeme broad with a strong dorsal keel. Synsternite 6+7 asymmetrical, complex, a portion often detached and forming an accessory sclerite flanking distiphallus in genital pouch; dorsal corner fused to sternite 8. Sternite 8 broadly fused to epandrium along right side. Epandrium more or less symmetrical, with a cleft above anterior edge of surstylus. Cerci small and medially fused. Subepandrial sclerite Y -shaped, articulated with cerci and surstyli. Surstylus broad, scoop-shaped, articulated with epandrium and subepandrial sclerite. Hypandrial arms weakly fused with ventral edge of epandrium; hypandrial apodeme well-developed, somewhat flattened, weakly fused with arms. Phallapodeme well-developed, curved and broadest distally. Postgonites long and bilobed apically, articulated with phallapodeme, hypandrium, and basiphallus. Pregonites tiny, more or less fused with postgonites. Ejaculatory apodeme small, often lost in dissections. Basiphallus usually with both epiphallus and preepiphallus. Distiphallus complex, structure variable between species.

Female postabdomen: Abdomen telescoping, usually retracted in preserved specimens. Tergites and sternites 6–7 usually weakly sclerotized, narrow. Tergite 8 heavily sclerotized, sternite 8 divided medially, heavily sclerotized. Epiproct and hypoproct moderately sclerotized. Cerci simple, not fused with epiproct or each other. Three spermathecae, one pair sharing a duct and the other on a separate duct.